Scholars@Duke
Christopher R Monroe

Christopher R Monroe

Gilhuly Family Presidential Distinguished Professor
Electrical and Computer Engineering
c.monroe@duke.edu
130 Hudson Hall, Box 90291, Durham, NC 27708
the Chesterfield Building, 701 W. Main St., Durham, NC 27701

Selected Publications

Fast Photon-Mediated Entanglement of Continuously Cooled Trapped Ions for Quantum Networking.

Journal Article Physical review letters · August 2024 We entangle two cotrapped atomic barium ion qubits by collecting single visible photons from each ion through in vacuo 0.8 NA objectives, interfering them through an integrated fiber beam splitter and detecting them in coincidence. This projects the qubits ... Full text Cite

Ion trap with in-vacuum high numerical aperture imaging for a dual-species modular quantum computer.

Journal Article The Review of scientific instruments · March 2024 Photonic interconnects between quantum systems will play a central role in both scalable quantum computing and quantum networking. Entanglement of remote qubits via photons has been demonstrated in many platforms; however, improving the rate of entanglemen ... Full text Cite

Experimental implementation of an efficient test of quantumness

Journal Article Physical Review A · January 1, 2024 A test of quantumness is a protocol where a classical user issues challenges to a quantum device to determine if it exhibits nonclassical behavior, under certain cryptographic assumptions. Recent attempts to implement such tests on current quantum computer ... Full text Cite

Phase transition in magic with random quantum circuits

Journal Article Nature Physics · January 1, 2024 Magic is a property of quantum states that enables universal fault-tolerant quantum computing using simple sets of gate operations. Understanding the mechanisms by which magic is created or destroyed is, therefore, a crucial step towards efficient and prac ... Full text Cite

Interactive cryptographic proofs of quantumness using mid-circuit measurements

Journal Article Nature Physics · November 1, 2023 The ability to perform measurements in the middle of a quantum circuit is a powerful resource. It underlies a wide range of applications, from remote state preparation to quantum error correction. Here we apply mid-circuit measurements for a particular tas ... Full text Cite

Continuous symmetry breaking in a trapped-ion spin chain.

Journal Article Nature · November 2023 One-dimensional systems exhibiting a continuous symmetry can host quantum phases of matter with true long-range order only in the presence of sufficiently long-range interactions1. In most physical systems, however, the interactions are short-ra ... Full text Cite

Digital quantum simulation of NMR experiments.

Journal Article Science advances · November 2023 Simulations of nuclear magnetic resonance (NMR) experiments can be an important tool for extracting information about molecular structure and optimizing experimental protocols but are often intractable on classical computers for large molecules such as pro ... Full text Cite

Demonstration of three- and four-body interactions between trapped-ion spins

Journal Article Nature Physics · October 1, 2023 Quantum processors use the native interactions between effective spins to simulate Hamiltonians or execute quantum gates. In most processors, the native interactions are pairwise, limiting the efficiency of controlling entanglement between many qubits. The ... Full text Cite

Programmable Quantum Simulations of Bosonic Systems with Trapped Ions.

Journal Article Physical review letters · July 2023 Trapped atomic ion crystals are a leading platform for quantum simulations of spin systems, with programmable and long-range spin-spin interactions mediated by excitations of phonons in the crystal. We describe a complementary approach for quantum simulati ... Full text Cite

Programmable N -Body Interactions with Trapped Ions

Journal Article PRX Quantum · July 1, 2023 Trapped atomic ion qubits or effective spins are a powerful quantum platform for quantum computation and simulation, featuring densely connected and efficiently programmable interactions between the spins. While native interactions between trapped-ion spin ... Full text Cite

Colloquium: Quantum and classical discrete time crystals

Journal Article Reviews of Modern Physics · July 1, 2023 The spontaneous breaking of time-translation symmetry has led to the discovery of a new phase of matter: the discrete time crystal. Discrete time crystals exhibit rigid subharmonic oscillations that result from a combination of many-body interactions, coll ... Full text Cite

Quantum Simulation for High-Energy Physics

Journal Article PRX Quantum · April 1, 2023 It is for the first time that quantum simulation for high-energy physics (HEP) is studied in the U.S. decadal particle-physics community planning, and in fact until recently, this was not considered a mainstream topic in the community. This fact speaks of ... Full text Cite

Next-generation trapped-ion quantum computing system

Conference Quantum 2.0: Proceedings Optica Quantum 2.0 Conference and Exhibition · January 1, 2023 In this work we discuss the progress of commissioning the next-generation trapped-ion quantum computing system. Heating rates, coherence times, background gas collision rates, individual-addressing cross-talk and other factors contributing to the gate fide ... Full text Cite

Progress towards a three-node ion-trap quantum network

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Trapped ions are one of the leading platforms for quantum computation and networking, with long coherence times and high fidelity qubit operation. We exploit these attributes to build a quantum network with the use of three trapped ion modules connected vi ... Full text Cite

Engineering Dynamically Decoupled Quantum Simulations with Trapped Ions

Journal Article PRX Quantum · January 1, 2023 An external drive can improve the coherence of a quantum many-body system by averaging out noise sources. It can also be used to realize models that are inaccessible in the static limit, through Floquet Hamiltonian engineering. The full possibilities for c ... Full text Cite

Cross-platform comparison of arbitrary quantum states.

Journal Article Nature communications · November 2022 As we approach the era of quantum advantage, when quantum computers (QCs) can outperform any classical computer on particular tasks, there remains the difficult challenge of how to validate their performance. While algorithmic success can be easily verifie ... Full text Cite

N-Body Interactions between Trapped Ion Qubits via Spin-Dependent Squeezing.

Journal Article Physical review letters · August 2022 We describe a simple protocol for the single-step generation of N-body entangling interactions between trapped atomic ion qubits. We show that qubit state-dependent squeezing operations and displacement forces on the collective atomic motion can generate f ... Full text Cite

Measurement-induced quantum phases realized in a trapped-ion quantum computer

Journal Article Nature Physics · July 1, 2022 Many-body open quantum systems balance internal dynamics against decoherence and measurements induced by interactions with an environment1,2. Quantum circuits composed of random unitary gates with interspersed projective measurements represent a minimal mo ... Full text Open Access Cite

Many-Body Quantum Teleportation via Operator Spreading in the Traversable Wormhole Protocol

Journal Article Physical Review X · July 1, 2022 By leveraging shared entanglement between a pair of qubits, one can teleport a quantum state from one particle to another. Recent advances have uncovered an intrinsically many-body generalization of quantum teleportation, with an elegant and surprising con ... Full text Cite

Control of Transverse Motion for Quantum Gates on Individually Addressed Atomic Qubits

Journal Article PRX Quantum · March 1, 2022 Individual trapped atomic qubits represent one of the most promising technologies to scale quantum computers, owing to their low idle errors and the ability to implement a full set of reconfigurable gate operations via focused optical fields. However, the ... Full text Cite

Optimizing Stabilizer Parities for Improved Logical Qubit Memories.

Journal Article Physical review letters · December 2021 We study variants of Shor's code that are adept at handling single-axis correlated idling errors, which are commonly observed in many quantum systems. By using the repetition code structure of the Shor's code basis states, we calculate the logical channel ... Full text Cite

Quantum circuits for the realization of equivalent forms of one-dimensional discrete-time quantum walks on near-term quantum hardware

Journal Article Physical Review A · December 1, 2021 Quantum walks are a promising framework for developing quantum algorithms and quantum simulations. They represent an important test case for the application of quantum computers. Here we present different forms of discrete-time quantum walks (DTQWs) and sh ... Full text Cite

Observation of Stark many-body localization without disorder.

Journal Article Nature · November 2021 Thermalization is a ubiquitous process of statistical physics, in which a physical system reaches an equilibrium state that is defined by a few global properties such as temperature. Even in isolated quantum many-body systems, limited to reversible dynamic ... Full text Cite

Fault-tolerant control of an error-corrected qubit.

Journal Article Nature · October 2021 Quantum error correction protects fragile quantum information by encoding it into a larger quantum system1,2. These extra degrees of freedom enable the detection and correction of errors, but also increase the control complexity of the encoded l ... Full text Open Access Cite

Comparison of cloud-based ion trap and superconducting quantum computer architectures

Journal Article AVS Quantum Science · September 1, 2021 Quantum computing represents a radical departure from conventional approaches to information processing, offering the potential for solving problems that can never be approached classically. While large-scale quantum computer hardware is still in developme ... Full text Cite

Erratum: Quantum approximate optimization of the long-range Ising model with a trapped-ion quantum simulator (Proc. Natl. Acad. Sci. U.S.A. (2020) 117 (25396-25401) DOI: 10.1073/pnas.2006373117)

Journal Article Proceedings of the National Academy of Sciences of the United States of America · August 24, 2021 PHYSICS Correction to Supporting Information for “Quantum approximate optimization of the long-range Ising model with a trapped-ion quantum simulator,” by Guido Pagano, Aniruddha Bapat, Patrick Becker, Katherine S. Collins, Arinjoy De, Paul W. Hess, Harvey ... Full text Cite

Many-body thermodynamics on quantum computers via partition function zeros.

Journal Article Science advances · August 2021 Partition functions are ubiquitous in physics: They are important in determining the thermodynamic properties of many-body systems and in understanding their phase transitions. As shown by Lee and Yang, analytically continuing the partition function to the ... Full text Cite

Observation of a prethermal discrete time crystal.

Journal Article Science (New York, N.Y.) · June 2021 Extending the framework of statistical physics to the nonequilibrium setting has led to the discovery of previously unidentified phases of matter, often catalyzed by periodic driving. However, preventing the runaway heating that is associated with driving ... Full text Cite

Domain-wall confinement and dynamics in a quantum simulator

Journal Article Nature Physics · June 1, 2021 Particles subject to confinement experience an attractive potential that increases without bound as they separate. A prominent example is colour confinement in particle physics, in which baryons and mesons are produced by quark confinement. Confinement can ... Full text Cite

Programmable quantum simulations of spin systems with trapped ions

Journal Article Reviews of Modern Physics · April 7, 2021 Laser-cooled and trapped atomic ions form an ideal standard for the simulation of interacting quantum spin models. Effective spins are represented by appropriate internal energy levels within each ion, and the spins can be measured with near-perfect effici ... Full text Cite

Probing many-body localization on a noisy quantum computer

Journal Article Physical Review A · March 1, 2021 A disordered quantum system of interacting particles exhibits localized behavior when the disorder is large compared to the interaction strength. Studying this phenomenon on a quantum computer with no, or limited, error correction is challenging because ev ... Full text Cite

Quantum Simulators: Architectures and Opportunities

Journal Article PRX Quantum · January 1, 2021 Quantum simulators are a promising technology on the spectrum of quantum devices from specialized quantum experiments to universal quantum computers. These quantum devices utilize entanglement and many-particle behavior to explore and solve hard scientific ... Full text Cite

Development of Quantum Interconnects (QuICs) for Next-Generation Information Technologies

Journal Article PRX Quantum · January 1, 2021 Just as "classical"information technology rests on a foundation built of interconnected information-processing systems, quantum information technology (QIT) must do the same. A critical component of such systems is the "interconnect,"a device or process th ... Full text Cite

Quantum Computer Systems for Scientific Discovery

Journal Article PRX Quantum · January 1, 2021 The great promise of quantum computers comes with the dual challenges of building them and finding their useful applications. We argue that these two challenges should be considered together, by codesigning full-stack quantum computer systems along with th ... Full text Cite

Resource-optimized fermionic local-hamiltonian simulation on a quantum computer for quantum chemistry

Journal Article Quantum · January 1, 2021 The ability to simulate a fermionic system on a quantum computer is expected to revolutionize chemical engineering, materials design, nuclear physics, to name a few. Thus, optimizing the simulation circuits is of significance in harnessing the power of qua ... Full text Cite

Character of motional modes for entanglement and sympathetic cooling of mixed-species trapped-ion chains

Journal Article Physical Review A · January 1, 2021 Modular mixed-species ion-trap networks are a promising framework for scalable quantum information processing, where one species acts as a memory qubit and another as a communication qubit. This architecture requires high-fidelity mixed-species entangling ... Full text Cite

Ground-state energy estimation of the water molecule on a trapped-ion quantum computer

Journal Article npj Quantum Information · December 1, 2020 Quantum computing leverages the quantum resources of superposition and entanglement to efficiently solve computational problems considered intractable for classical computers. Examples include calculating molecular and nuclear structure, simulating strongl ... Full text Cite

Seletalisib for Activated PI3Kδ Syndromes: Open-Label Phase 1b and Extension Studies.

Journal Article Journal of immunology (Baltimore, Md. : 1950) · December 2020 Mutations in two genes can result in activated PI3Kδ syndrome (APDS), a rare immunodeficiency disease with limited therapeutic options. Seletalisib, a potent, selective PI3Kδ inhibitor, was evaluated in patients with APDS1 and APDS2. In the phase 1b study ... Full text Cite

Generation of thermofield double states and critical ground states with a quantum computer.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · October 2020 Finite-temperature phases of many-body quantum systems are fundamental to phenomena ranging from condensed-matter physics to cosmology, yet they are generally difficult to simulate. Using an ion trap quantum computer and protocols motivated by the quantum ... Full text Cite

Quantum approximate optimization of the long-range Ising model with a trapped-ion quantum simulator.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · October 2020 Quantum computers and simulators may offer significant advantages over their classical counterparts, providing insights into quantum many-body systems and possibly improving performance for solving exponentially hard problems, such as optimization and sati ... Full text Cite

Many-Body Dephasing in a Trapped-Ion Quantum Simulator.

Journal Article Physical review letters · September 2020 How a closed interacting quantum many-body system relaxes and dephases as a function of time is a fundamental question in thermodynamic and statistical physics. In this Letter, we analyze and observe the persistent temporal fluctuations after a quantum que ... Full text Cite

Quantum walks and Dirac cellular automata on a programmable trapped-ion quantum computer.

Journal Article Nature communications · July 2020 The quantum walk formalism is a widely used and highly successful framework for modeling quantum systems, such as simulations of the Dirac equation, different dynamics in both the low and high energy regime, and for developing a wide range of quantum algor ... Full text Cite

Efficient Ground-State Cooling of Large Trapped-Ion Chains with an Electromagnetically-Induced-Transparency Tripod Scheme.

Journal Article Physical review letters · July 2020 We report the electromagnetically-induced-transparency (EIT) cooling of a large trapped ^{171}Yb^{+} ion chain to the quantum ground state. Unlike conventional EIT cooling, we engage a four-level tripod structure and achieve fast sub-Doppler cooling over a ... Full text Cite

Towards analog quantum simulations of lattice gauge theories with trapped ions

Journal Article Physical Review Research · April 8, 2020 Gauge field theories play a central role in modern physics and are at the heart of the Standard Model of elementary particles and interactions. Despite significant progress in applying classical computational techniques to simulate gauge theories, it has r ... Full text Cite

Discrete Time Crystals

Journal Article Annual Review of Condensed Matter Physics · March 10, 2020 Experimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems is those that do not thermalize under their own isolated q ... Full text Cite

Toward convergence of effective-field-theory simulations on digital quantum computers

Journal Article Physical Review A · December 16, 2019 We report results for simulating an effective field theory to compute the binding energy of the deuteron nucleus using a hybrid algorithm on a trapped-ion quantum computer. Two increasingly complex unitary coupled-cluster ansatze have been used to compute ... Full text Cite

Benchmarking an 11-qubit quantum computer.

Journal Article Nature communications · November 2019 The field of quantum computing has grown from concept to demonstration devices over the past 20 years. Universal quantum computing offers efficiency in approaching problems of scientific and commercial interest, such as factoring large numbers, searching d ... Full text Cite

Heisenberg-scaling measurement protocol for analytic functions with quantum sensor networks

Journal Article Physical Review A · October 7, 2019 We generalize past work on quantum sensor networks to show that, for d input parameters, entanglement can yield a factor O(d) improvement in mean-squared error when estimating an analytic function of these parameters. We show that the protocol is optimal f ... Full text Cite

Training of quantum circuits on a hybrid quantum computer.

Journal Article Science advances · October 2019 Generative modeling is a flavor of machine learning with applications ranging from computer vision to chemical design. It is expected to be one of the techniques most suited to take advantage of the additional resources provided by near-term quantum comput ... Full text Cite

High purity single photons entangled with an atomic qubit.

Journal Article Optics express · September 2019 Trapped atomic ions are an ideal candidate for quantum network nodes, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. The integrity of this photonic ... Full text Cite

Two-qubit entangling gates within arbitrarily long chains of trapped ions

Journal Article Physical Review A · August 26, 2019 Ion trap quantum computers are based on modulating the Coulomb interaction between atomic ion qubits using external forces. However, the spectral crowding of collective motional modes could pose a challenge to the control of such interactions for large num ... Full text Open Access Cite

Entanglement as a resource for quantum networking

Conference Proceedings Rochester Conference on Coherence and Quantum Optics, CQO 2019 · August 4, 2019 We examine the viability of quantum repeaters based on two-species trapped ion modules for long-distance quantum key distribution. We discuss the dependence of the quantum key distribution rate on various experimental parameters, including coupling efficie ... Cite

Parallel entangling operations on a universal ion-trap quantum computer.

Journal Article Nature · August 2019 The circuit model of a quantum computer consists of sequences of gate operations between quantum bits (qubits), drawn from a universal family of discrete operations1. The ability to execute parallel entangling quantum gates offers efficiency gai ... Full text Cite

Quantum repeaters based on two species trapped ions

Journal Article New Journal of Physics · July 1, 2019 We examine the viability of quantum repeaters based on two-species trapped ion modules for long-distance quantum key distribution. Repeater nodes comprised of ion-trap modules of co-trapped ions of distinct species are considered. The species used for comm ... Full text Cite

The U.S. National Quantum Initiative: From Act to action.

Journal Article Science (New York, N.Y.) · May 2019 Full text Cite

Confined Quasiparticle Dynamics in Long-Range Interacting Quantum Spin Chains.

Journal Article Physical review letters · April 2019 We study the quasiparticle excitation and quench dynamics of the one-dimensional transverse-field Ising model with power-law (1/r^{α}) interactions. We find that long-range interactions give rise to a confining potential, which couples pairs of domain wall ... Full text Cite

Verified quantum information scrambling.

Journal Article Nature · March 2019 Quantum scrambling is the dispersal of local information into many-body quantum entanglements and correlations distributed throughout an entire system. This concept accompanies the dynamics of thermalization in closed quantum systems, and has recently emer ... Full text Cite

The US National Quantum Initiative

Journal Article Quantum Science and Technology · February 22, 2019 Quantum technology exploits the unique quantum features of superposition, entanglement, and fundamental metrology metrics in order to create new opportunities in secure communication, high-precision sensing, and revolutionary computers. Quantum technology ... Full text Cite

Quantum computing and simulation with trapped atomic ions

Conference Optics InfoBase Conference Papers · January 1, 2019 I will review some of the latest results in both gate-based quantum computing and analog quantum simulation, speculating on how this platform can realistically be scaled in the near future. ... Full text Cite

Quantum repeaters based on two species trapped ions

Conference Optics InfoBase Conference Papers · January 1, 2019 We consider two species trapped ions as building blocks of large-scale quantum repeaters across trans-continental distances. Key generation rate dependence on experimental gate error rates, operation time and coupling efficiency to a fiber is discussed. ... Full text Cite

Entanglement as a resource for quantum networking

Conference Optics InfoBase Conference Papers · January 1, 2019 We examine the viability of quantum repeaters based on two-species trapped ion modules for long-distance quantum key distribution. We discuss the dependence of the quantum key distribution rate on various experimental parameters, including coupling efficie ... Cite

Cryogenic trapped-ion system for large scale quantum simulation

Journal Article Quantum Science and Technology · January 1, 2019 Trapped-ion systems are among the most promising hardware candidates for large scale quantum computing and quantum simulation. In order to scale up such devices, it is necessary to engineer extreme-high vacuum (XHV) environments to prevent background gas f ... Full text Cite

Measuring the Rényi entropy of a two-site Fermi-Hubbard model on a trapped ion quantum computer

Journal Article Physical Review A · November 26, 2018 The efficient simulation of correlated quantum systems is a promising near-term application of quantum computers. Here, we present a measurement of the second Rényi entropy of the ground state of the two-site Fermi-Hubbard model on a five-qubit programmabl ... Full text Cite

Quantum Repeaters Based on Two-Species Trapped Ions

Conference IEEE Photonics Society Summer Topicals Meeting Series, SUM 2018 · September 5, 2018 Trapped ions technology is the most promising candidate for construction of the large-scale quantum computers, quantum repeaters and quantum networks. Quantum networks require matter qubits with fast quantum gates and measurement, efficient coupling to pho ... Full text Cite

Machine learning assisted readout of trapped-ion qubits

Journal Article Journal of Physics B: Atomic, Molecular and Optical Physics · August 17, 2018 We reduce measurement errors in a quantum computer using machine learning techniques. We exploit a simple yet versatile neural network to classify multi-qubit quantum states, which is trained using experimental data. This flexible approach allows the incor ... Full text Cite

Demonstration of a Bayesian quantum game on an ion-trap quantum computer

Journal Article Quantum Science and Technology · July 10, 2018 We demonstrate a Bayesian quantum game on an ion-trap quantum computer with five qubits. The players share an entangled pair of qubits and perform rotations on their qubit as the strategy choice. Two five-qubit circuits are sufficient to run all 16 possibl ... Full text Cite

Observation of Hopping and Blockade of Bosons in a Trapped Ion Spin Chain.

Journal Article Physical review letters · February 2018 The local phonon modes in a Coulomb crystal of trapped ions can represent a Hubbard system of coupled bosons. We selectively prepare single excitations at each site and observe free hopping of a boson between sites, mediated by the long-range Coulomb inter ... Full text Cite

Robust 2-Qubit Gates in a Linear Ion Crystal Using a Frequency-Modulated Driving Force.

Journal Article Physical review letters · January 2018 In an ion trap quantum computer, collective motional modes are used to entangle two or more qubits in order to execute multiqubit logical gates. Any residual entanglement between the internal and motional states of the ions results in loss of fidelity, esp ... Full text Open Access Cite

Trapped ion single-photon emitter for quantum networking

Conference Optics InfoBase Conference Papers · January 1, 2018 We demonstrate a single-photon source for quantum networking based on a single trapped 138Ba+ ion subject to pulsed excitation, and measure a second-order autocorrelation of g(2)(0) = (8.1 ± 2.3) × 10-5 without any background subtraction. ... Full text Cite

Complete 3-Qubit Grover search on a programmable quantum computer.

Journal Article Nature communications · December 2017 The Grover quantum search algorithm is a hallmark application of a quantum computer with a well-known speedup over classical searches of an unsorted database. Here, we report results for a complete three-qubit Grover search algorithm using the scalable qua ... Full text Cite

Demonstration of Two-Atom Entanglement with Ultrafast Optical Pulses.

Journal Article Physical review letters · December 2017 We demonstrate quantum entanglement of two trapped atomic ion qubits using a sequence of ultrafast laser pulses. Unlike previous demonstrations of entanglement mediated by the Coulomb interaction, this scheme does not require confinement to the Lamb-Dicke ... Full text Cite

Non-thermalization in trapped atomic ion spin chains.

Journal Article Philosophical transactions. Series A, Mathematical, physical, and engineering sciences · December 2017 Linear arrays of trapped and laser-cooled atomic ions are a versatile platform for studying strongly interacting many-body quantum systems. Effective spins are encoded in long-lived electronic levels of each ion and made to interact through laser-mediated ... Full text Cite

Reconfigurable and programmable ion trap quantum computer

Conference 2017 IEEE International Conference on Rebooting Computing, ICRC 2017 - Proceedings · November 28, 2017 We present progress on the construction and operation of a room-temperature quantum computer built with trapped atomic ion qubits. Based on the technological underpinnings of atomic clocks that define time, atomic qubits are standards of quantum informatio ... Full text Cite

Observation of a many-body dynamical phase transition with a 53-qubit quantum simulator.

Journal Article Nature · November 2017 A quantum simulator is a type of quantum computer that controls the interactions between quantum bits (or qubits) in a way that can be mapped to certain quantum many-body problems. As it becomes possible to exert more control over larger numbers of qubits, ... Full text Cite

Fault-tolerant quantum error detection.

Journal Article Science advances · October 2017 Quantum computers will eventually reach a size at which quantum error correction becomes imperative. Quantum information can be protected from qubit imperfections and flawed control operations by encoding a single logical qubit in multiple physical qubits. ... Full text Cite

Ultrafast creation of large Schrödinger cat states of an atom.

Journal Article Nature communications · September 2017 Mesoscopic quantum superpositions, or Schrödinger cat states, are widely studied for fundamental investigations of quantum measurement and decoherence as well as applications in sensing and quantum information science. The generation and maintenance of suc ... Full text Cite

Observation of prethermalization in long-range interacting spin chains.

Journal Article Science advances · August 2017 Although statistical mechanics describes thermal equilibrium states, these states may or may not emerge dynamically for a subsystem of an isolated quantum many-body system. For instance, quantum systems that are near-integrable usually fail to thermalize i ... Full text Cite

Multispecies Trapped-Ion Node for Quantum Networking.

Journal Article Physical review letters · June 2017 Trapped atomic ions are a leading platform for quantum information networks, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. However, performing both ... Full text Cite

Experimental comparison of two quantum computing architectures.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · March 2017 We run a selection of algorithms on two state-of-the-art 5-qubit quantum computers that are based on different technology platforms. One is a publicly accessible superconducting transmon device (www.Researchibm.com/ibm-q) with limited connectivity ... Full text Cite

Observation of a discrete time crystal.

Journal Article Nature · March 2017 Spontaneous symmetry breaking is a fundamental concept in many areas of physics, including cosmology, particle physics and condensed matter. An example is the breaking of spatial translational symmetry, which underlies the formation of crystals and the pha ... Full text Cite

Comparing the architectures of the first programmable quantum computers

Conference Optics InfoBase Conference Papers · January 1, 2017 Cite

Interacting many-body spin systems that fail to quantum thermalize

Conference Optics InfoBase Conference Papers · January 1, 2017 This talk will describe the experimental observation of two mechanisms -- many-body localization (MBL) and prethermalization -- that prevent interacting quantum systems from attaining thermal equilibrium. ... Full text Cite

Entanglement of quantum memories by interfering distinguishable photons

Conference Optics InfoBase Conference Papers · January 1, 2017 Time-resolved photon detection can be used to generate entanglement between nonidentical qubits that emit distinguishable photons, which may be necessary for future modular quantum systems. We experimentally realize this process using remotely trapped ytte ... Full text Cite

Engineering large Stark shifts for control of individual clock state qubits

Journal Article Physical Review A · October 7, 2016 In quantum information science, the external control of qubits must be balanced with the extreme isolation of the qubits from the environment. Atomic qubit systems typically mitigate this balance through the use of gated laser fields that can create superp ... Full text Cite

Many-body localization in a quantum simulator with programmable random disorder

Journal Article Nature Physics · October 1, 2016 When a system thermalizes it loses all memory of its initial conditions. Even within a closed quantum system, subsystems usually thermalize using the rest of the system as a heat bath. Exceptions to quantum thermalization have been observed, but typically ... Full text Cite

High-resolution adaptive imaging of a single atom

Journal Article Nature Photonics · August 31, 2016 Optical imaging systems are used extensively in the life and physical sciences because of their ability to non-invasively capture details on the microscopic and nanoscopic scales. Such systems are often limited by source or detector noise, image distortion ... Full text Cite

Demonstration of a small programmable quantum computer with atomic qubits.

Journal Article Nature · August 2016 Quantum computers can solve certain problems more efficiently than any possible conventional computer. Small quantum algorithms have been demonstrated on multiple quantum computing platforms, many specifically tailored in hardware to implement a particular ... Full text Cite

Kaleidoscope of quantum phases in a long-range interacting spin-1 chain

Journal Article Physical Review B · May 11, 2016 Motivated directly by recent trapped-ion quantum simulation experiments, we carry out a comprehensive study of the phase diagram of a spin-1 chain with XXZ-type interactions that decay as 1/rα, using a combination of finite and infinite-size DMRG calculati ... Full text Cite

Active stabilization of ion trap radiofrequency potentials

Journal Article Review of Scientific Instruments · May 1, 2016 We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscil ... Full text Cite

Quantum Connections

Journal Article Scientific American · April 19, 2016 Full text Cite

What Do We Really Know About Translaminar Pressure?: Response.

Journal Article Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society · March 2016 Full text Cite

Co-designing a scalable quantum computer with trapped atomic ions

Journal Article npj Quantum Information · January 1, 2016 The first generation of quantum computers are on the horizon, fabricated from quantum hardware platforms that may soon be able to tackle certain tasks that cannot be performed or modelled with conventional computers. These quantum devices will not likely b ... Full text Cite

Sensing Atomic Motion from the Zero Point to Room Temperature with Ultrafast Atom Interferometry

Journal Article Physical Review Letters · November 16, 2015 We sense the motion of a trapped atomic ion using a sequence of state-dependent ultrafast momentum kicks. We use this atom interferometer to characterize a nearly pure quantum state with n=1 phonon and accurately measure thermal states ranging from near th ... Full text Cite

Simulating the Haldane phase in trapped-ion spins using optical fields

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · July 30, 2015 We propose to experimentally explore the Haldane phase in spin-one XXZ antiferromagnetic chains using trapped ions. We show how to adiabatically prepare the ground states of the Haldane phase, demonstrate their robustness against sources of experimental no ... Full text Cite

Modular entanglement of atomic qubits using photons and phonons

Journal Article Nature Physics · January 11, 2015 Quantum entanglement is the central resource behind quantum information science, from quantum computation and simulation to enhanced metrology and secure communication. These applications require the quantum control of large networks of qubits to realize g ... Full text Cite

Realization of a quantum integer-spin chain with controllable interactions

Journal Article Physical Review X · January 1, 2015 The physics of interacting integer-spin chains has been a topic of intense theoretical interest, particularly in the context of symmetry-protected topological phases. However, there has not been a controllable model system to study this physics experimenta ... Full text Cite

Quantum gates with phase stability over space and time

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · October 14, 2014 The performance of a quantum information processor depends on the precise control of phases introduced into the system during quantum gate operations. As the number of operations increases with the complexity of a computation, the phases of the gates at di ... Full text Cite

Entanglement of distinguishable quantum memories

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · October 10, 2014 Time-resolved photon detection can be used to generate entanglement between distinguishable photons. This technique can be extended to entangle quantum memories that emit photons with different frequencies and identical temporal profiles without the loss o ... Full text Cite

Beat note stabilization of mode-locked lasers for quantum information processing

Journal Article Optics Letters · June 1, 2014 We stabilize a chosen radio frequency beat note between two optical fields derived from the same mode-locked laser pulse train in order to coherently manipulate quantum information. This scheme does not require access or active stabilization of the laser r ... Full text Cite

Optimal quantum control of multimode couplings between trapped ion qubits for scalable entanglement

Journal Article Physical Review Letters · May 14, 2014 We demonstrate entangling quantum gates within a chain of five trapped ion qubits by optimally shaping optical fields that couple to multiple collective modes of motion. We individually address qubits with segmented optical pulses to construct multipartite ... Full text Cite

Large-scale modular quantum-computer architecture with atomic memory and photonic interconnects

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · February 13, 2014 The practical construction of scalable quantum-computer hardware capable of executing nontrivial quantum algorithms will require the juxtaposition of different types of quantum systems. We analyze a modular ion trap quantum-computer architecture with a hie ... Full text Cite

Coherent imaging spectroscopy of a quantum many-body spin system

Journal Article Science · January 1, 2014 Quantum simulators, in which well-controlled quantum systems are used to reproduce the dynamics of less understood ones, have the potential to explore physics inaccessible to modeling with classical computers. However, checking the results of such simulati ... Full text Cite

Non-local propagation of correlations in quantum systems with long-range interactions

Journal Article Nature · January 1, 2014 Themaximum speed with which information can propagate in a quantum many-body system directly affects how quickly disparate parts of the system can become correlated1-4 andhowdifficult the systemwill be to describe numerically5. For systems with only short- ... Full text Cite

Quantum control of qubits and atomic motion using ultrafast laser pulses

Journal Article Applied Physics B: Lasers and Optics · January 1, 2014 Pulsed lasers offer significant advantages over continuous wave (CW) lasers in the coherent control of qubits. Here we review the theoretical and experimental aspects of controlling the internal and external states of individual trapped atoms with pulse tr ... Full text Cite

Quantum catalysis of magnetic phase transitions in a quantum simulator

Journal Article Physical Review Letters · September 5, 2013 We control quantum fluctuations to create the ground state magnetic phases of a classical Ising model with a tunable longitudinal magnetic field using a system of 6 to 10 atomic ion spins. Because of the long-range Ising interactions, the various ground st ... Full text Cite

Focus on quantum simulation

Journal Article New Journal of Physics · August 1, 2013 The endeavour to control increasingly larger systems of particles at the quantum level is a natural goal, and will be a driving force for the physical sciences in the coming decades. The control of a many-body system at the highest level possible can indee ... Full text Cite

Experimental performance of a quantum simulator: Optimizing adiabatic evolution and identifying many-body ground states

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · July 31, 2013 We use local adiabatic evolution to experimentally create and determine the ground-state spin ordering of a fully connected Ising model with up to 14 spins. Local adiabatic evolution - in which the system evolution rate is a function of the instantaneous e ... Full text Cite

Ultrafast spin-motion entanglement and interferometry with a single atom

Journal Article Physical Review Letters · May 13, 2013 We report entanglement of a single atom's hyperfine spin state with its motional state in a time scale of less than 3 ns. We engineer a short train of intense laser pulses to impart a spin-dependent momentum transfer of ±2âk. Using pairs of momentum kicks, ... Full text Cite

Emergence and frustration of magnetism with variable-range interactions in a quantum simulator

Journal Article Science · January 1, 2013 Frustration, or the competition between interacting components of a network, is often responsible for the emergent complexity of many-body systems. For instance, frustrated magnetism is a hallmark of poorly understood systems such as quantum spin liquids, ... Full text Cite

Quantum networks with atoms, phonons, and photons

Conference Optics InfoBase Conference Papers · January 1, 2013 Trapped atomic ions are the most advanced experimental platform for many-body entanglement and quantum information processing. Recent results in local entanglement between trapped ions for uses in quantum simulation of nontrivial spin models will be discus ... Full text Cite

Quantum networks with atoms and photons

Conference Journal of Physics: Conference Series · January 1, 2013 Trapped atomic ions are standards for quantum information processing, as all of the fundamental quantum operations have been demonstrated in small collections of atoms. Current work is concentrated on scaling ion traps to larger numbers of interacting qubi ... Full text Cite

Scaling the Ion Trap Quantum Processor

Journal Article SCIENCE · 2013 Full text Cite

Trapped ions for testing foundations of quantum theory

Conference AIP Conference Proceedings · December 1, 2012 Here we give details of an experiment using trapped ions and photons that demonstrates a Bell inequality violation with a Bell signal of S = 2.22±0.07. This type of experimental setup has the potential to close both the detection and locality loopholes and ... Full text Cite

Coherent error suppression in multiqubit entangling gates

Journal Article Physical Review Letters · July 11, 2012 We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped ion systems. This extension of the Mølmer-Sørensen gate can theoretically suppress th ... Full text Cite

Photon collection from a trapped ion-cavity system

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · June 11, 2012 We present the design and implementation of a trapped ion-cavity QED system. A single ytterbium ion is confined by a micron-scale ion trap inside a 2-mm optical cavity. The ion is coherently pumped by near-resonant laser light while the cavity output is mo ... Full text Cite

Quantum simulation of spin models on an arbitrary lattice with trapped ions

Journal Article New Journal of Physics · 2012 A collection of trapped atomic ions represents one of the most attractive platforms for the quantum simulation of interacting spin networks and quantum magnetism. Spin-dependent optical dipole forces applied to an ion crystal create long-range effective sp ... Full text Cite

A cavity QED-Ion trap system for a scalable quantum network

Conference Optics InfoBase Conference Papers · December 1, 2011 We observe an enhancement of the spontaneous emission from a single trapped ytterbium ion into a cavity QED system. This technique helps to scale up an ion-photon quantum network. © 2010 Optical Society of America. ... Cite

Quantum simulation of the transverse Ising model with trapped ions

Journal Article New Journal of Physics · October 1, 2011 Crystals of trapped atomic ions are among the most promising platforms for the quantum simulation of many-body quantum physics. Here, we describe recent developments in the simulation of quantum magnetic spin models with trapped 171Yb+ ions, and discuss th ... Full text Cite

Private random number generation through remote atom entanglement

Conference 2011 IEEE Photonics Society Summer Topical Meeting Series · September 26, 2011 Random number generation is vital for a wide range of applications, including numerical simulation, gambling, and cryptography. However, verifying the randomness of a bit stream generated by a device is exceedingly difficult. Even if a sequence of numbers ... Full text Cite

Onset of a quantum phase transition with a trapped ion quantum simulator.

Journal Article Nature communications · July 2011 A quantum simulator is a well-controlled quantum system that can follow the evolution of a prescribed model whose behaviour may be difficult to determine. A good example is the simulation of a set of interacting spins, where phase transitions between vario ... Full text Cite

Sharp phase transitions in a small frustrated network of trapped ion spins

Journal Article Physical Review Letters · June 8, 2011 Sharp quantum phase transitions typically require a large system with many particles. Here we show that, for a frustrated fully connected Ising spin network represented by trapped atomic ions, the competition between different spin orders leads to rich pha ... Full text Cite

Ion-photon networks for scalable quantum computing

Conference Optics InfoBase Conference Papers · January 1, 2011 Trapped ions entangled via photonic interactions are promising avenues for quan- tum information processing. Here, we report advances towards combining photonic gates be- tween distant ions with Coulombic gates between nearby ions to demonstrate scalable q ... Full text Cite

Mode-locked laser driven gates for trapped ion quantum information processing

Conference Proceedings of the 20th International Conference on Laser Spectroscopy, ICOLS 2011 · January 1, 2011 Single- and multi-qubit operations for trapped ion hyperfine or Zeeman qubits are typically implemented by continuous-wave lasers driving stimulated Raman transitions. Here we report two distinct regimes for driving these transitions with mode-locked pulse ... Cite

A cavity QED-ion trap system for a scalable quantum network

Conference 2011 Conference on Lasers and Electro-Optics: Laser Science to Photonic Applications, CLEO 2011 · January 1, 2011 We observe an enhancement of the spontaneous emission from a single trapped ytterbium ion into a cavity QED system. This technique helps to scale up an ion-photon quantum network. © 2011 OSA. ... Full text Cite

Modular universal scalable ion-trap quantum computer (MUSIQC)

Journal Article AIP Conference Proceedings · 2011 We describe a scalable architecture for general-purpose quantum computation based on trapped ions and photonic interconnect network. The quantum computer is made up of several elementary logic units (ELUs) each containing a modest number of trapped ions re ... Full text Cite

Quantum optical networks with trapped ions

Conference Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010 · October 11, 2010 Trapped atomic ion quantum memories can be locally entangled via the Coulomb interaction and remotely entangled based on probabilistic photonic interfaces. Both versions are presented, highlighting their features and drawbacks when applied to quantum compu ... Cite

Quantum simulation and phase diagram of the transverse-field Ising model with three atomic spins

Journal Article Physical Review B - Condensed Matter and Materials Physics · August 27, 2010 We perform a quantum simulation of the Ising model with a transverse field using a collection of three trapped atomic ion spins. By adiabatically manipulating the Hamiltonian, we directly probe the ground state for a wide range of fields and form of the Is ... Full text Cite

Ultrafast gates for single atomic qubits

Journal Article Physical Review Letters · August 26, 2010 We demonstrate single-qubit operations on a trapped atom hyperfine qubit using a single ultrafast pulse from a mode-locked laser. We shape the pulse from the laser and perform a π rotation of the qubit in less than 50 ps with a population transfer exceedin ... Full text Cite

Quantum simulation of frustrated Ising spins with trapped ions

Journal Article Nature · June 3, 2010 A network is frustrated when competing interactions between nodes prevent each bond from being satisfied. This compromise is central to the behaviour of many complex systems, from social and neural networks to protein folding and magnetism. Frustrated netw ... Full text Cite

Colloquium: Quantum networks with trapped ions

Journal Article Reviews of Modern Physics · April 28, 2010 Quantum computation and communication exploit the quantum properties of superposition and entanglement in order to perform tasks that may be impossible using classical means. In this Colloquium recent experimental and theoretical progress in the generation ... Full text Cite

Quantum computers

Journal Article Nature · April 19, 2010 Over the past several decades, quantum information science has emerged to seek answers to the question: can we gain some advantage by storing, transmitting and processing information encoded in systems that exhibit unique quantum properties? Today it is un ... Full text Cite

Random numbers certified by Bellĝs theorem

Journal Article Nature · April 15, 2010 Randomness is a fundamental feature of nature and a valuable resource for applications ranging from cryptography and gambling to numerical simulation of physical and biological systems. Random numbers, however, are difficult to characterize mathematically, ... Full text Cite

Entanglement of atomic qubits using an optical frequency comb

Journal Article Physical Review Letters · April 5, 2010 We demonstrate the use of an optical frequency comb to coherently control and entangle atomic qubits. A train of off-resonant ultrafast laser pulses is used to efficiently and coherently transfer population between electronic and vibrational states of trap ... Full text Cite

Phonon-mediated entanglement for trapped ion quantum computing

Journal Article Reports on Progress in Physics · March 17, 2010 Trapped ions are a near ideal system to study quantum information processing due to the high degree of control over the ion's external confinement and internal degrees of freedom. We demonstrate the key steps necessary for trapped ion quantum computing and ... Full text Cite

Quantum entanglement and information

Conference Optics InfoBase Conference Papers · January 1, 2010 Quantum systems can store entangled superpositions of information, offering the possibility of enhanced performance in many applications. This talk will outline hardware used to make large scale entangled states, using atoms and light. © 2010 Optical Socie ... Full text Cite

Quantum optical networks with trapped ions

Conference Optics InfoBase Conference Papers · January 1, 2010 Trapped atomic ion quantum memories can be locally entangled via the Coulomb interaction and remotely entangled based on probabilistic photonic interfaces. Both versions are presented, highlighting their features and drawbacks when applied to quantum compu ... Full text Cite

Quantum logic between distant trapped ions

Journal Article International Journal of Quantum Information · January 1, 2010 Trapped atomic ions have proven to be one of the most promising candidates for the realization of quantum computation due to their long trapping times, excellent coherence properties, and exquisite control of the internal atomic states. Integrating ions (q ... Full text Cite

Protocol for hybrid entanglement between a trapped atom and a quantum dot

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · December 30, 2009 We propose a quantum optical interface between an atomic and solid-state system. We show that quantum states in a single trapped atom can be entangled with the states of a semiconductor quantum dot through their common interaction with a classical laser fi ... Full text Cite

Trapped ion qubit operations with ultrashort pulses

Conference Optics InfoBase Conference Papers · December 1, 2009 We describe an experiment to achieve ultrafast qubit operations on trapped 171Yb+ ions. We plan to use a series of short optical pulses to perform bit rotations and multi-bit entangling gates independent of ion temperature. © 2009 Optical Society of Americ ... Cite

Large-scale quantum computation in an anharmonic linear ion trap

Journal Article EPL · November 20, 2009 We propose a large-scale quantum computer architecture by more easily stabilizing a single large linear ion chain in a very simple trap geometry. By confining ions in an anharmonic linear trap with nearly uniform spacing between ions, we show that high-fid ... Full text Cite

High fidelity quantum entanglement and spin-spin dynamics using multiple phonon modes of several trapped ions

Conference 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 16, 2009 We demonstrate quantum entanglement and global spin dynamics between a few trapped ions, using lasers that couple to all modes of transverse motion in a way that could be scaled to large numbers of spins. © 2009 Optical Society of America. ... Cite

Teleportation of quantum information between distant atomic qubits

Conference 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 16, 2009 We teleport quantum information between two distant ytterbium ions trapped in different vacuum chambers separated by one meter. Full state tomography shows that the heralded probabilistic process employed has a fidelity of 90%. © 2009 Optical Society of Am ... Cite

A heralded quantum gate between remote atoms

Conference 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 16, 2009 We implement a probabilistic entangling gate between two distant trapped ytterbium ions and measure an average gate fidelity of 90%. © 2009 Optical Society of America. ... Cite

Trapped ion qubit operations with ultrashort pulses

Conference 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 16, 2009 We describe an experiment to achieve ultrafast qubit operations on trapped 171Yb+ ions. We plan to use a series of short optical pulses to perform bit rotations and multi-bit entangling gates independent of ion temperature. © 2009 Optical Society of Americ ... Cite

Protocols and techniques for a scalable atom-photon quantum network

Journal Article Fortschritte der Physik · November 1, 2009 Quantum networks based on atomic qubits and scattered photons provide a promising way to build a largescale quantum information processor. We review quantum protocols for generating entanglement and operating gates between two distant atomic qubits, which ... Full text Cite

Demonstration of a scalable, multiplexed ion trap for quantum information processing

Journal Article Quantum Information and Computation · November 1, 2009 A scalable, multiplexed ion trap for quantum information processing is fabricated and tested. The trap design and fabrication process are optimized for scalability to small trap size and large numbers of interconnected traps, and for integration of control ... Cite

Entanglement and Tunable Spin-Spin Couplings between Trapped Ions Using Multiple Transverse Modes

Journal Article Physical Review Letters · September 16, 2009 We demonstrate tunable spin-spin couplings between trapped atomic ions, mediated by laser forces on multiple transverse collective modes of motion. A σxσx-type Ising interaction is realized between quantum bits stored in the ground hyperfine clock states o ... Full text Cite

Measurement of the lifetime of the 6p P2 1/2 o level of Yb+

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · August 10, 2009 We present a precise measurement of the lifetime of the 6p P2 1/2 o excited state of a single trapped ytterbium ion (Yb+). A time-correlated single-photon counting technique is used, where ultrafast pulses excite the ion and the emitted photons are coupled ... Full text Cite

Heralded quantum gate between remote quantum memories

Journal Article Physical Review Letters · June 25, 2009 We demonstrate a probabilistic entangling quantum gate between two distant trapped ytterbium ions. The gate is implemented between the hyperfine "clock" state atomic qubits and mediated by the interference of two emitted photons carrying frequency encoded ... Full text Cite

Quantum teleportation between distant matter qubits

Journal Article Science · January 23, 2009 Quantum teleportation is the faithful transfer of quantum states between systems, relying on the prior establishment of entanglement and using only classical communication during the transmission. We report teleportation of quantum information between atom ... Full text Cite

A heralded quantum gate between remote atoms

Conference Optics InfoBase Conference Papers · January 1, 2009 We implement a probabilistic entangling gate between two distant trapped ytterbium ions and measure an average gate fidelity of 90%. © 2009 Optical Society of America. ... Full text Cite

Trapped ion qubit operations with ultrashort pulses

Conference Optics InfoBase Conference Papers · January 1, 2009 We describe an experiment to achieve ultrafast qubit operations on trapped 171Yb+ ions. We plan to use a series of short optical pulses to perform bit rotations and multi-bit entangling gates independent of ion temperature. © 2009 Optical Society of Americ ... Full text Cite

Measurement-based entanglement and quantum information processing with remote ions

Conference Optics InfoBase Conference Papers · January 1, 2009 We implement a probabilistic entangling gate between two remote trapped ytterbium ions and measure an average gate fidelity of 89%. The entangled state of the ions violates a Bell inequality. © 2009 Optical Society of America. ... Full text Cite

High fidelity quantum entanglement and spin-spin dynamics using multiple phonon modes of several trapped ions

Conference Optics InfoBase Conference Papers · January 1, 2009 We demonstrate quantum entanglement and global spin dynamics between a few trapped ions, using lasers that couple to all modes of transverse motion in a way that could be scaled to large numbers of spins. © 2009 Optical Society of America. ... Full text Cite

Teleportation of quantum information between distant atomic qubits

Conference Optics InfoBase Conference Papers · January 1, 2009 We teleport quantum information between two distant ytterbium ions trapped in different vacuum chambers separated by one meter. Full state tomography shows that the heralded probabilistic process employed has a fidelity of 90%. © 2009 Optical Society of Am ... Full text Cite

Measurement-based entanglement and quantum information processing with remote ions

Conference Optics InfoBase Conference Papers · January 1, 2009 We implement a probabilistic entangling gate between two remote trapped ytterbium ions and measure an average gate fidelity of 89%. The entangled state of the ions violates a Bell inequality. © 2009 Optical Society of America. ... Cite

Robust probabilistic quantum information processing with atoms, photons, and atomic ensembles

Journal Article Advances in Atomic, Molecular and Optical Physics · November 7, 2008 In this article, we review several new approaches to scalable and robust quantum communication, state engineering, and quantum computation. We consider the use of atomic ensembles, linear optical elements, and trapped ions for this purpose, all having sign ... Full text Cite

Trapped ion quantum networks

Conference Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · September 15, 2008 We describe the use of a photonic coupling between remote trapped ions for applications in quantum communication and quantum computing. © 2008 Optical Society of America. ... Full text Cite

On the transport of atomic ions in linear and multidimensional ion trap arrays

Journal Article Quantum Information and Computation · July 1, 2008 Trapped atomic ions have become one of the most promising architectures for a quantum computer, and current effort is now devoted to the transport of trapped ions through complexsegmentediontrapstructuresinordertoscaleuptomuchlargernumbersof trapped ion qu ... Full text Cite

Bell inequality violation with two remote atomic qubits

Journal Article Physical Review Letters · April 18, 2008 We observe violation of a Bell inequality between the quantum states of two remote Yb+ ions separated by a distance of about 1 m with the detection loophole closed. The heralded entanglement of two ions is established via interference and joint detection o ... Full text Cite

Very cold trapped atoms in a vapor cell

Chapter · January 1, 2008 We have produced a very cold sample of spin-polarired trapprd atoms. The technique used dramatically simplifies the production of laser-cooled atoms. In this experiment. 1.8 ⨯ 107neutral cesium atoms were optically captured directly from a low-pressure vap ... Full text Cite

A magnetic suspension system for atoms and bar magnets

Chapter · January 1, 2008 A three dimensional magnetic confinement system is presented which will trap both macroscopic and atomic magnetic dipoles. The dipole is confined by dc and oscillating magnetic fields, and its motion is described by the Mathieu equation. Most aspect3 of th ... Full text Cite

Fundamental physics with optically trapped atoms

Chapter · January 1, 2008 We discuss two experiments which appear feasible because of the progress in laser trapping and cooling of neutral atoms. First, using laser trapping, it should be possible trap a number of radioactive isotopes of cesium and francium. Precise measurements o ... Full text Cite

Multiply loaded, ac magnetic trap for neutral atoms

Chapter · January 1, 2008 We have demonstrated an oscillating-gradient magnetic trap for confining cesium atoms in the lowest-energy spin state. In this state spin-flip collisions are energetically forbidden and thus the primary density- and temperature-limiting process for magneti ... Full text Cite

The low (temperature) road toward bose-einstein condensation in optically and magnetically trapped cesium atoms

Chapter · January 1, 2008 There is considerable reason to pursue the extreme limits of low temperature and high density that can be achieved in an atomic vapor. First there is the intrinsic interest in the trapping and cooling of atoms, and the behavior of atoms in new regimes of t ... Full text Cite

Measurement of Cs-Cs elastic scattering at T =30 μK

Chapter · January 1, 2008 We have measured the elastic collision cross section for spin polarized atomic cesium. Neutral cesium atoms are optically cooled, then loaded into a dc magnetic trap. We infer the scattering rate from the rate at which anisotropies in the initial energy di ... Full text Cite

Observation of the cesium clock transition using laser-cooled atoms in a vapor cell

Chapter · January 1, 2008 Cesium atoms in a vapor cell have been trapped and cooled by using light from laser diodes. The 6s F = 4, m = 0 →6.9 F = 3, m = 0 hyperfine clock transition was excited as these atoms then fell 2.5 cm in darkness. We observed a linewidth of 8 Hz with good ... Full text Cite

Remapping the quantum frontier

Other Physics World · January 1, 2008 Full text Cite

Quantum computing with ions

Journal Article Scientific American · January 1, 2008 Full text Cite

Manipulation and detection of a trapped Yb+ hyperfine qubit

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · November 19, 2007 We demonstrate the use of trapped ytterbium ions as quantum bits for quantum information processing. We implement fast, efficient state preparation and state detection of the first-order magnetic field-insensitive hyperfine levels of Yb+171, with a measure ... Full text Cite

Magneto-optical trapping of cadmium

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · October 11, 2007 We report the laser cooling and confinement of Cd atoms in a magneto-optical trap and characterize the loading process from the background Cd vapor. The trapping laser drives the S01 → P11 transition at 229 nm in this two-electron atom and also photoionize ... Full text Cite

Entanglement of single-atom quantum bits at a distance

Journal Article Nature · September 6, 2007 Quantum information science involves the storage, manipulation and communication of information encoded in quantum systems, where the phenomena of superposition and entanglement can provide enhancements over what is possible classically. Large-scale quantu ... Full text Cite

Quantum interference of electromagnetic fields from two remote trapped atomic ions

Conference Optics InfoBase Conference Papers · January 1, 2007 We observe quantum Hong-Ou-Mandel interference between electromagnetic fields emitted from two remote trapped ytterbium ions. This result points the way toward scaling to large entangled networks of remote qubits. © 2007 Optical Society of America. ... Full text Cite

Magneto-optical trap of cadmium

Conference Optics InfoBase Conference Papers · January 1, 2007 We achieve the first magneto-optical trap of Cadmium. When integrated with a nearby ion trap, this allows for the possibility of protecting quantum information from environment perturbations via charge neutralization of trapped ions. © 2007 Optical Society ... Full text Cite

Quantum networking with photons and trapped atoms (invited)

Journal Article Journal of the Optical Society of America B: Optical Physics · January 1, 2007 Distributed quantum information processing requires a reliable quantum memory and a faithful carrier of quantum information. Atomic qubits have very long coherence times and are thus excellent candidates for quantum information storage, whereas photons are ... Full text Cite

The trap technique

Journal Article IEEE Spectrum · January 1, 2007 Quantum computing started when Peter Shor, a theoretical mathematician at Bell Labs discovered an algorithm for a quantum computer that can efficiently determine the prime factors of a large integer. Shor's algorithm has sparked a worldwide race to build a ... Full text Cite

Quantum interference of photon pairs from two remote trapped atomic ions

Journal Article Nature Physics · January 1, 2007 Trapped atomic ions are among the most attractive implementations of quantum bits for applications in quantum-information processing, owing to their long trapping lifetimes and long coherence times. Although nearby trapped ions can be entangled through the ... Full text Cite

Quantum networking with trapped atomic ions

Conference LEOS Summer Topical Meeting · December 1, 2006 Cite

Efficient photoionization loading of trapped ions with ultrafast pulses

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · December 1, 2006 Atomic cadmium ions are loaded into radiofrequency ion traps by photoionization of atoms in a cadmium vapor with ultrafast laser pulses. The photoionization is driven through an intermediate atomic resonance with a frequency-quadrupled mode-locked Ti:sapph ... Full text Cite

Scaling and suppression of anomalous heating in ion traps

Journal Article Physical Review Letters · September 18, 2006 We measure and characterize anomalous motional heating of an atomic ion confined in the lowest quantum levels of a novel rf ion trap that features moveable electrodes. The scaling of heating with electrode proximity is measured, and when the electrodes are ... Full text Cite

Trapped ion quantum computation with transverse phonon modes

Journal Article Physical Review Letters · August 14, 2006 We propose a scheme to implement quantum gates on any pair of trapped ions immersed in a large linear crystal, using interaction mediated by the transverse phonon modes. Compared with the conventional approaches based on the longitudinal phonon modes, this ... Full text Cite

Ultrafast coherent excitation of a trapped ion qubit for fast gates and photon frequency qubits

Journal Article Physical Review Letters · August 4, 2006 We demonstrate ultrafast coherent excitation of an atomic qubit stored in the hyperfine levels of a single trapped cadmium ion. Such ultrafast excitation is crucial for entangling networks of remotely located trapped ions through the interference of photon ... Full text Cite

Probabilistic quantum gates between remote atoms through interference of optical frequency qubits

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · June 23, 2006 We propose a scheme to perform probabilistic quantum gates on remote trapped atom qubits through interference of optical frequency qubits. The method does not require localization of the atoms to the Lamb-Dicke limit, and is not sensitive to interferometer ... Full text Cite

Erratum: Zero-point cooling and low heating of trapped Cd+111 ions (Physical Review A (2004) 70 (043408))

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · June 7, 2006 Full text Cite

Arbitrary-speed quantum gates within large ion crystals through minimum control of laser beams

Journal Article Europhysics Letters · February 15, 2006 We propose a scheme to implement arbitrary-speed quantum entangling gates on two trapped ions immersed in a large linear crystal of ions, with minimal control of laser beams. For gate speeds slower than the oscillation frequencies in the trap, a single app ... Full text Cite

T-junction ion trap array for two-dimensional ion shuttling, storage, and manipulation

Journal Article Applied Physics Letters · January 30, 2006 We demonstrate a two-dimensional 11-zone ion trap array, where individual laser-cooled atomic ions are stored, separated, shuttled, and swapped. The trap geometry consists of two linear rf-ion trap sections that are joined at a 90°angle to form a T-shaped ... Full text Cite

Ion trap in a semiconductor chip

Journal Article Nature Physics · January 15, 2006 The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ions. Work on miniaturizing electromagnetic traps to ... Full text Cite

Broadband laser cooling of trapped atoms with ultrafast pulses

Journal Article Journal of the Optical Society of America B: Optical Physics · January 1, 2006 We demonstrate broadband laser cooling of atomic ions in an rf trap using ultrafast pulses from a mode-locked laser. The temperature of a single ion is measured by observing the size of a time-averaged image of the ion in the known harmonic trap potential. ... Full text Cite

Scalable quantum computation with photons and trapped ions

Conference Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS · January 1, 2006 Ultrafast laser pulses can be used for fast quantum gates and entangling gates offering an alternative method to scale quantum computing systems. We implement fundamental components of these entangling gates. © 2006 IEEE. ... Full text Cite

Near-perfect simultaneous measurement of a qubit register

Journal Article Quantum Information and Computation · January 1, 2006 Simultaneous measurement of multiple qubits stored in hyperfine levels of trapped 111 Cd+ ions is realized with an intensified charge-coupled device (CCD) imager. A general theory of fluorescence detection for hyperfine qubits is presented and applied to e ... Cite

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2006 We report precision measurements of the excited state lifetime of the 5p P 1/2 2 and 5p P 3/2 2 levels of a single trapped Cd+ ion. Combining ion trap and ultrafast laser technologies, the ion is excited with picosecond laser pulses from a mode-locked lase ... Full text Cite

Quantum computing with trapped ion hyperfine qubits

Chapter · December 1, 2005 We discuss the basic aspects of quantum information processing with trapped ions, including the principles of ion trapping, preparation and detection of hyper-fine qubits, single-qubit operations and multi-qubit entanglement protocols. Recent experimental ... Full text Cite

Ion trap transducers for quantum electromechanical oscillators

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · October 1, 2005 An enduring challenge for contemporary physics is to experimentally observe and control quantum behavior in macroscopic systems. We show that a single trapped atomic ion could be used to probe the quantum nature of a mesoscopic mechanical oscillator precoo ... Full text Cite

Phase control of trapped ion quantum gates

Journal Article Journal of Optics B: Quantum and Semiclassical Optics · October 1, 2005 There are several known schemes for entangling trapped ion quantum bits for large-scale quantum computation. Most are based on an interaction between the ions and external optical fields, coupling internal qubit states of trapped ions to their Coulomb-coup ... Full text Cite

Spin-dependent forces on trapped ions for phase-stable quantum gates and entangled states of spin and motion

Journal Article Physical Review Letters · April 22, 2005 Favored schemes for trapped-ion quantum logic gates use bichromatic laser fields to couple internal qubit states with external motion through a "spin-dependent force." We introduce a new degree of freedom in this coupling that reduces its sensitivity to ph ... Full text Cite

Ion trap networking: Cold, fast, and small

Chapter · January 1, 2005 A large-scale ion trap quantum computer will require low-noise entanglement schemes and methods for networking ions between different regions. We report work on both fronts, with the entanglement of two trapped cadmium ions following a phase-insensitive Mo ... Full text Cite

Ion trap networking: Cold, fast, and small

Conference Laser Spectroscopy - Proceedings of the 17th International Conference, ICOLS 2005 · January 1, 2005 A large-scale ion trap quantum computer will require low-noise entanglement schemes and methods for networking ions between different regions. We report work on both fronts, with the entanglement of two trapped cadmium ions following a phase-insensitive Mo ... Cite

Implementation of Grover's quantum search algorithm in a scalable system

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2005 We report the implementation of Grover's quantum search algorithm in the scalable system of trapped atomic ion quantum bits. Any one of four possible states of a two-qubit memory is marked, and following a single query of the search space, the marked eleme ... Full text Cite

Entanglement of trapped-ion clock states

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2005 A Mølmer-Sørensen entangling gate is realized for pairs of trapped Cd+111 ions using magnetic-field insensitive "clock" states and an implementation offering reduced sensitivity to optical phase drifts. The gate is used to generate the complete set of four ... Full text Cite

Zero-point cooling and low heating of trapped 111Cd + ions

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · October 1, 2004 Ground-state laser cooling of single 111Cd + ions was discussed. Heating rates of trapped ion motion were measured for two different trapping geometries and electrode materials. No effort was made to shield the electrodes from the atomic Cd source. The low ... Full text Cite

Quantum computing with trapped ion hyperfine qubits

Journal Article Quantum Information Processing · October 1, 2004 We discuss the basic aspects of quantum information processing with trapped ions, including the principles of ion trapping, preparation and detection of hyperfine qubits, single-qubit operations and multi-qubit entanglement protocols. Recent experimental a ... Full text Cite

Experimental Bell inequality violation with an atom and a photon.

Journal Article Physical review letters · August 2004 We report the measurement of a Bell inequality violation with a single atom and a single photon prepared in a probabilistic entangled state. This is the first demonstration of such a violation with particles of different species. The entanglement character ... Full text Cite

Control of Trapped-Ion Quantum States with Optical Pulses

Journal Article Physical Review Letters · March 19, 2004 The control-theoretical analysis of control of trapped-ion quantum states is described with optical pulses in large Hilbert spaces. The resonant bichromatic fields were applied to completely uncontrollable and controllable systems. The specific temporal sh ... Full text Cite

Observation of entanglement between a single trapped atom and a single photon

Journal Article Nature · March 11, 2004 An outstanding goal in quantum information science is the faithful mapping of quantum information between a stable quantum memory and a reliable quantum communication channel. This would allow, for example, quantum communication over remote distances, quan ... Full text Cite

Planar ion trap geometry for microfabrication

Journal Article Applied Physics B: Lasers and Optics · March 1, 2004 We describe a novel high aspect ratio radiofrequency linear ion trap geometry that is amenable to modern microfabrication techniques. The ion trap electrode structure consists of a pair of stacked conducting cantilevers resulting in confining fields that t ... Full text Cite

A microscale quadrupole mass spectrometer for ion species analysis

Conference 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit · January 1, 2004 Investigators have identified a quadrupole structure that uses non-traditional geometry with rectangular cantilevered electrodes and that is amenable to semiconductor fabrication. Despite the revolutiotiary electrode geometry, the proposed microscale quadr ... Full text Cite

Observation of entanglement between a single trapped atom and a single photon

Conference OSA Trends in Optics and Photonics Series · January 1, 2004 We report the first observation of entanglement between a stationary quantum memory and a 'flying' quantum bit. Coincident quantum state measurements between a single trapped atomic ion and its emitted photon directly verify the entanglement. ... Cite

Scalable trapped ion quantum computation with a probabilistic ion-photon mapping

Journal Article Quantum Information and Computation · January 1, 2004 We propose a method for scaling trapped ions for large-scale quantum computation and communication based on a probabilistic ion-photon mapping. Deterministic quantum gates between remotely located trapped ions can be achieved through detection of spontaneo ... Cite

Clean and scalable quantum logic with trapped ions

Conference Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · December 1, 2003 Experimental progress in constructing a quantum computer with a collection of trapped ions is discussed, with emphasis on how various technical hurdles may be circumvented. ©2003 Optical Society of America. ... Cite

Atomic qubit manipulations with an electro-optic modulator

Journal Article Optics Letters · September 1, 2003 A high-frequency electro-optic phase modulator (EOM) was used to demonstrate stimulated Raman transitions (SRT) Rabi oscillations on a single trapped 111Cd+ ion. The techniques of shaping the sideband spectrum or creating an interference pattern between mu ... Full text Cite

Quantum dynamics of single trapped ions

Journal Article Reviews of Modern Physics · January 1, 2003 Single trapped ions represent elementary quantum systems that are well isolated from the environment. They can be brought nearly to rest by laser cooling, and both their internal electronic states and external motion can be coupled to and manipulated by li ... Full text Cite

Decoherence of motional superpositions of a trapped ion

Conference Chaos, Solitons and Fractals · January 1, 2003 We summarize experiments on the decoherence of motional superposition states of single trapped ions which were carried out at NIST. The decoherence was characterized by the loss of contrast in interference experiments involving superpositions of two motion ... Full text Cite

Clean and scalable quantum logic with trapped ions

Conference Optics InfoBase Conference Papers · January 1, 2003 Experimental progress in constructing a quantum computer with a collection of trapped ions is discussed, with emphasis on how various technical hurdles may be circumvented. ... Cite

Architecture for a large-scale ion-trap quantum computer.

Journal Article Nature · June 2002 Among the numerous types of architecture being explored for quantum computers are systems utilizing ion traps, in which quantum bits (qubits) are formed from the electronic states of trapped ions and coupled through the Coulomb interaction. Although the el ... Full text Cite

Quantum information processing with atoms and photons.

Journal Article Nature · March 2002 Quantum information processors exploit the quantum features of superposition and entanglement for applications not possible in classical devices, offering the potential for significant improvements in the communication and processing of information. Experi ... Full text Cite

Sympathetic cooling of trapped Cd+ isotopes

Journal Article Physical Review A. Atomic, Molecular, and Optical Physics · January 1, 2002 Sympathetic cooling of a single trapped 112Cd+ ion was performed through Doppler cooling of a neighboring 114Cd+ ion. The Cd+ D2 line resonant near 214.5 nm was generated by quadrupling a Ti:sapphire laser. The ultraviolet fluorescence from the ions was co ... Full text Cite

Experimental demonstration of entanglement-enhanced rotation angle estimation using trapped ions

Journal Article Physical Review Letters · June 25, 2001 Experimental measurements of rotation angle in an atomic ensemble were performed. The measurements include all sources of noise. In an application to a Ramsey spectroscopy experiment, an increased precision in frequency measurement compared to an idealized ... Full text Cite

Experimental violation of a Bell's inequality with efficient detection.

Journal Article Nature · February 2001 Local realism is the idea that objects have definite properties whether or not they are measured, and that measurements of these properties are not affected by events taking place sufficiently far away. Einstein, Podolsky and Rosen used these reasonable as ... Full text Cite

A decoherence-free quantum memory using trapped ions.

Journal Article Science (New York, N.Y.) · February 2001 We demonstrate a decoherence-free quantum memory of one qubit. By encoding the qubit into the decoherence-free subspace (DFS) of a pair of trapped 9Be+ ions, we protect the qubit from environment-induced dephasing that limits the storage time of a qubit co ... Full text Cite

Recent results in trapped-ion quantum computing at nist

Journal Article Quantum Information and Computation · January 1, 2001 We review recent experiments on entanglement, Bell's inequality, and decoherence-free subspaces in a quantum register of trapped 9Be+ ions. We have demonstrated entanglement of up to four ions [1] using the technique of Mølmer and Sørensen [2]. This method ... Cite

Scalable entanglement of trapped ions

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · December 1, 2000 Quantum entanglement is a fundamental element of schemes for quantum communication, cryptography, and computation. This article proposes and demonstrates a truly scalable entanglement technique. ... Cite

Superposition and quantum measurement of trapped atoms

Journal Article Annalen der Physik (Leipzig) · December 1, 2000 An overview is given on the ion trap experiments carried out at NIST. It is emphasized that many of the trapped-ion experiments share a close formal connection to those of cavity-quantum-electro dynamics (CQED), particularly those involving microwave field ... Full text Cite

Decoherence and decay of motional quantum states of a trapped atom coupled to engineered reservoirs

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · November 1, 2000 The decay of quantum states of a trapped atomic ion's harmonic motion interacting with several types of engineered reservoirs, and their decoherence were experimentally studied. A high temperature phase reservoir and a zero temperature amplitude reservoir ... Full text Cite

Experimental entanglement of four particles

Journal Article Nature · March 16, 2000 Quantum mechanics allows for many-particle wavefunctions that cannot be factorized into a product of single-particle wave-functions, even when the constituent particles are entirely distinct. Such 'entangled' states explicitly demonstrate the non-local cha ... Full text Cite

Decoherence of quantum superpositions through coupling to engineered reservoirs

Journal Article Nature · January 20, 2000 The theory of quantum mechanics applies to closed systems. In such ideal situations, a single atom can, for example, exist simultaneously in a superposition of two different spatial locations. In contrast, real systems always interact with their environmen ... Full text Cite

Sympathetic cooling of trapped ions for quantum logic

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2000 One limit to the fidelity of quantum logic operations on trapped ions arises from heating of the ions’ collective modes of motion. Sympathetic cooling of the ions during the logic operations may eliminate this source of errors. We discuss the benefits and ... Full text Cite

Heating of trapped ions from the quantum ground state

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2000 We have investigated motional heating of laser-cooled [Formula Presented] ions held in radio-frequency (Paul) traps. We have measured heating rates in a variety of traps with different geometries, electrode materials, and characteristic sizes. The results ... Full text Cite

Heating of trapped ions from the quantum ground state

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2000 In this study, heating from the ground state of trapped ions in different traps was measured. The magnitude of heating rates and the results of the size-scaling measurements were inconsistent with thermal electronic noise as the source of the heating. Over ... Cite

Sympathetic cooling of trapped ions for quantum logic

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2000 One limit to the fidelity of quantum logic operations on trapped ions arises from heating of the ions' collective modes of motion. Sympathetic cooling of the ions during the logic operations may eliminate this source of errors. We discuss the benefits and ... Cite

Decoherence of motional states of trapped ions

Journal Article Journal of Modern Optics · January 1, 2000 We have studied the decoherence of motional-state superpositions of single trapped ions caused by their coupling to fluctuating fields. We illustrate these studies by showing how Schrödinger-cat state superpositions decohere in the presence of purposely-ap ... Full text Cite

Quantum computing with trapped ions

Journal Article IQEC, International Quantum Electronics Conference Proceedings · January 1, 1999 The most promising physical system for the realization of a quantum computer is a collection of trapped atomic ions. Internal electronic states of the ions is shown to act as quantum bits, and with the use of quantum logic operations, they are coupled thro ... Full text Cite

Coherent Quantum State Manipulation of Trapped Atomic Ions

Journal Article Advances in Quantum Chemistry · December 1, 1998 A single, laser-cooled, trapped 9Be+ ion is used to investigate methods of coherent quantum-state synthesis. We create and characterize nonclassical states of motion including "Schrödinger-cat" states. A fundamental quantum logic gate is realized using the ... Full text Cite

Trapped ions, entanglement, and quantum computing

Conference Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1998 A miniature, elliptical ring rf (Paul) ion trap has been used in recent experiments toward realizing a quantum computer in a trapped ion system. With the combination of small spatial dimensions and high rf drive potentials, around 500 V amplitude, we have ... Full text Cite

Trapped-Ion quantum simulator

Journal Article Physica Scripta T · December 1, 1998 Coherent manipulations involving the quantized motional and internal states of a single trapped ion can be used to simulate the dynamics of other systems. We consider some examples, including the action of a Mach Zehnder interferometer which uses entangled ... Cite

Deterministic entanglement of two trapped ions

Journal Article Physical Review Letters · October 26, 1998 We have prepared the internal states of two trapped ions in both the Bell-like singlet and triplet entangled states. In contrast to all other experiments with entangled states of either massive particles or photons, we do this in a deterministic fashion, p ... Full text Cite

Quantum computing.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · September 1998 Full text Cite

Experimental Issues in Coherent Quantum-State Manipulation of Trapped Atomic Ions

Journal Article Journal of Research of the National Institute of Standards and Technology · January 1, 1998 Methods for, and limitations to, the generation of entangled states of trapped atomic ions are examined. As much as possible, state manipulations are described in terms of quantum logic operations since the conditional dynamics implicit in quantum logic is ... Full text Cite

Cooling the collective motion of trapped ions to initialize a quantum register

Journal Article Physical Review Letters · January 1, 1998 We report preparation in the ground state of collective modes of motion of two trapped 9Be+ ions. This is a crucial step towards realizing quantum logic gates which can entangle the ions' internal electronic states. We find that heating of the modes of rel ... Full text Cite

Experimental primer on the trapped ion quantum computer

Journal Article Fortschritte der Physik · January 1, 1998 The development of a quantum computer based on a system of trapped atomic ions is described, following the proposal of Cirac and Zoller. Initial results on a two-bit quantum logic gate are presented, and select experimental issues in scaling the system to ... Full text Cite

Quantum state manipulation of trapped atomic ions

Journal Article Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences · January 1, 1998 A single laser-cooled and trapped 9Be+ ion is used to investigate methods of coherent quantum-state synthesis and quantum logic. We create and characterize non-classical states of motion including 'Schrodinger-cat' states. A fundamental quantum logic gate ... Full text Cite

Quantum harmonic oscillator state synthesis and analysis

Conference Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1997 We laser-cool single beryllium ions in a Paul trap to the ground (n equals 0) quantum harmonic oscillator state with greater than 90% probability. From this starting point, we can put the atom into various quantum states of motion by application of optical ... Full text Cite

Experimental creation and measurement of motional quantum states of a trapped ion

Journal Article Brazilian Journal of Physics · June 1, 1997 We report the creation and full determination of several quantum states of motion of a 9Be+ ion bound in a rf (Paul) trap. The states are coherently prepared from an ion which has been initially laser cooled to the zero-point of motion. We create states ha ... Cite

Engineering and tomography of quantum states of motion of a trapped atom

Conference Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · January 1, 1997 The motional quantum state is fully reconstructed with the use of two schemes that determine the density matrix in the number state basis and the Wigner function. The techniques allow well-controlled experiments on decoherence and related phenomena on the ... Cite

Experimental preparation and measurement of quantum states of motion of a trapped atom

Journal Article Journal of Modern Optics · January 1, 1997 We report the creation and full determination of several quantum states of motion of a 9Be+ ion bound in a RF (Paul) trap. The states are coherently prepared from an ion which has been initially laser cooled to the zero-point of motion. We create states ha ... Full text Cite

Simplified quantum logic with trapped ions

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 1997 We describe a simplified scheme for quantum logic with a collection of laser-cooled trapped atomic ions. Building on the scheme of Cirac and Zoller, we show how the fundamental controlled-NOT gate between a collective mode of ion motion and the internal st ... Full text Cite

Shaping atoms in optical lattices

Other Nature · January 1, 1997 Full text Cite

Atomic physics in ion traps

Journal Article Physics World · January 1, 1997 Full text Cite

A "Schrödinger cat" superposition state of an atom

Journal Article Science · May 24, 1996 A "Schrödinger cat"-like state of matter was generated at the single atom level. A trapped 9Be+ ion was laser-cooled to the zero-point energy and then prepared in a superposition of spatially separated coherent harmonic oscillator states. This state was cr ... Full text Cite

Experimental determination of the motional quantum state of a trapped atom

Journal Article Physical Review Letters · January 1, 1996 We reconstruct the density matrices and Wigner functions for various quantum states of motion of a harmonically bound 9Be+ ion. We apply coherent displacements of different amplitudes and phases to the input state and measure the number state populations. ... Full text Cite

Generation of nonclassical motional states of a trapped atom

Journal Article Physical Review Letters · January 1, 1996 We report the creation of thermal, Fock, coherent, and squeezed states of motion of a harmonically bound 9Be+ ion. The last three states are coherently prepared from an ion which has been initially laser cooled to the zero point of motion. The ion is trapp ... Full text Cite

Nonclassical motional states of a trapped atom

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · January 1, 1996 This paper reports the creation of thermal, Fock, coherent, squeezed, and 'Schrodinger cat' states of motion of a single 9Be+ atomic ion that is confined in a Paul-rf trap. The thermal state of motion is created by Doppler cooling on the 313 nm 2S 1/2 → 2 ... Cite

Entangled states of trapped atoms for quantum logic and spectroscopy

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · January 1, 1996 A quantum computer is composed of quantum bits that can support superposition states and hence allow parallel processing for certain problems such as factorization. All quantum computations can, in principle, be reduced to a series of two-bit quantum logic ... Cite

Manipulating the Motion of a Single Trapped Atom

Journal Article Accounts of Chemical Research · January 1, 1996 Full text Cite

Single-atom quantum logic gate and "Schrödinger cat" state

Journal Article Optics and Photonics News · January 1, 1996 Full text Cite

Demonstration of a fundamental quantum logic gate

Journal Article Physical Review Letters · January 1, 1995 We demonstrate the operation of a two-bit "controlled-NOT" quantum logic gate, which, in conjunction with simple single-bit operations, forms a universal quantum logic gate for quantum computation. The two quantum bits are stored in the internal and extern ... Full text Cite

Paul Trap for Optical Frequency Standards

Journal Article IEEE Transactions on Instrumentation and Measurement · January 1, 1995 We describe a variant of the quadrupole rf (Paul) ion trap capable of localization of a trapped ion within much less than an optical wavelength (Lamb-Dicke regime). Attainment of the Lamb-Dicke regime reduces the sensitivity of the central absorption featu ... Full text Cite

Coaxial-resonator-driven rf (Paul) trap for strong confinement

Journal Article Physical Review A · January 1, 1995 We describe a variant of the quadrupole rf (Paul) ion trap capable of localization of a trapped ion to much less than an optical wavelength (Lamb-Dicke regime). The trapping potentials are generated by a high-Q, vacuum-compatible, quarter-wave resonator dr ... Full text Cite

Resolved-sideband Raman cooling of a bound atom to the 3D zero-point energy

Journal Article Physical Review Letters · January 1, 1995 We report laser cooling of a single Be+9 ion held in a rf (Paul) ion trap to where it occupies the quantum-mechanical ground state of motion. With the use of resolved-sideband stimulated Raman cooling, the zero point of motion is achieved 98% of the time i ... Full text Cite

Rf-trap apparatus for optical frequency standards

Conference CPEM Digest (Conference on Precision Electromagnetic Measurements) · December 1, 1994 A novel rf (Paul) ion trap apparatus, capable of providing extremely tight confinement is described. Strong localization of trapped ions reduces an important source of noise when using the ions as an optical frequency standard. Alternative cooling schemes, ... Cite

Very Deep rf Ion Trap

Conference Optics InfoBase Conference Papers · January 1, 1994 Cite

Measurement of Cs-Cs elastic scattering at T=30 K

Journal Article Physical Review Letters · January 1, 1993 We have measured the elastic collision cross section for spin polarized atomic cesium. Neutral cesium atoms are optically cooled, then loaded into a dc magnetic trap. We infer the scattering rate from the rate at which anisotropies in the initial energy di ... Full text Cite

The road to Bose-Einstein condensation in a vapor

Conference Optics InfoBase Conference Papers · January 1, 1992 Cite

An Oscillating-Gradient Magnetic Trap for Strong-Field-Seeking Neutral Atoms

Conference Optics InfoBase Conference Papers · January 1, 1991 Cite

Multiply loaded, ac magnetic trap for neutral atoms

Journal Article Physical Review Letters · January 1, 1991 We have demonstrated an oscillating-gradient magnetic trap for confining cesium atoms in the lowest-energy spin state. In this state spin-flip collisions are energetically forbidden and thus the primary density- and temperature-limiting process for magneti ... Full text Cite

Very cold trapped atoms in a vapor cell

Journal Article Physical Review Letters · January 1, 1990 We have produced a very cold sample of spin-polarized trapped atoms. The technique used dramatically simplifies the production of laser-cooled atoms. In this experiment, 1.8×107 neutral cesium atoms were optically captured directly from a low-pressure vapo ... Full text Cite

Atomic collisions in an optical trap

Conference Optics InfoBase Conference Papers · January 1, 1989 Cite

Collisional losses from a light-force atom trap

Journal Article Physical Review Letters · January 1, 1989 We have studied the collisional loss rates for very cold cesium atoms held in a spontaneous-force optical trap. In contrast with previous work, we find that collisions involving excitation by the trapping light fields are the dominant loss mechanism. We al ... Full text Cite