Shailesh Chandrasekharan

Building our Universe with Qubits - Physics Department Colloquium · November 13, 2025 Keynote/Named Lecture Indian Institute of Technology, Kanpur, Kanpur, India

Lecture Series on Qubit Regularization - Lectures given to graduate students and postodcs · November 10, 2025 - November 14, 2025 Instructional Course, Workshop, or Symposium Indian Institute of Technology, Kanpur, Kanpur, India

Confined and Deconfined Phases of Qubit Regularized Lattice Gauge Theories - Contributed talk to the "42nd International Symposium on Lattice Field Theory" · November 2, 2025 - November 8, 2025 International Meeting or Conference Tata Institute for Fundamental Research, Mumbai, India

Confined and Deconfined Phases of Qubit Regularized Lattice Gauge Theories - Invited Theory Seminar · October 9, 2025 Invited Talk Iowa State University, Ames, Iowa

Lattice Gauge Theory - Pedagogical Talk given to Students and Postdocs · October 1, 2025 Lecture Duke University, Duke, NC

Monomer-Dimer-Tensor-Network Basis For Lattice Gauge Theories - Invited Theory Seminar · April 29, 2025 Invited Talk International Center for Theoretical Studies, Bengaluru, India

Quantum Computing in Lattice Field Theory Opportunities and Challenges - Keynote speaker at the workshop on "Quantum Computing for Lattice Field Theory and High Energy Physics" · March 25, 2025 Keynote/Named Lecture Southampton University, Southampton, UK

Sign Problem Free Qubit Regularized Hamiltonian Lattice Gauge Theory - Invited plenary speaker at the international conference on "Sign Problem in QCD and Beyond." · January 20, 2025 - January 24, 2025 International Meeting or Conference University of Bern, Bern, Switzerland

Symmetric Mass Generation: A Historical Perspective from Lattice Field Theory - Emergent Phenomena of Strongly-Interacting Conformal Field Theories and Beyond · September 4, 2023 - September 15, 2023 Invited Talk Aspen Center for Physics, Aspen, Colorado

Worldline approach to fermions - Sign Problem Workshop · July 24, 2023 - July 29, 2023 Invited Talk Peyresq, France

Learning more about the magic of Wilson’s Renormalization Group · May 12, 2023 Invited Talk International Center for Theoretical Sciences, Bengaluru India

Qubit Regularization of Quantum Field Theories · November 11, 2022 Invited Talk City College of New York, New York Invited theory seminar at the City College of New York

Quantum field theories via qubit regularization of lattice spin and gauge models - Bootstrapping Nature: Non-Perturbative Approaches to Critical Phenomena · November 4, 2022 Instructional Course, Workshop, or Symposium Galileo Galilei Institute, Online Attendance Invited talk at the workshop

Sign Problems in Few Body Physics in the Worldline Formulation - SIGN-2022 · September 5, 2022 - September 9, 2022 International Meeting or Conference Tel Aviv University, Tel Aviv, Israel Inivited talk at the workshop on Sign problems in QCD and Beyond, organized by Tel Aviv University

Building our Universe with Qubits - IMSc Diamond Jubiliee Distinguished Lecture · August 12, 2022 Keynote/Named Lecture Institute for Mathematical Sciences, Chennai, India Invited Distinguished Lecture/Colloquium

A simple qubit regularization scheme for SU(N) lattice gauge theories · August 1, 2022 Lecture Invited Seminar

Qubit Regularization: Asymptotic Freedom - Invited Lecture · July 25, 2022 Lecture International Center for Theoretical Sciences, Bengaluru India Invited Lecture

Introductory Lectures on Qubit Regularization · June 27, 2022 - June 28, 2022 Instructional Course, Workshop, or Symposium Saha Institute for Nuclear Physics, Kolkata, India I was invited to give three lectures on qubit regularization covering two days.

Qubit Regularization, Qubit Embedding Algebra and Asymptotic Freedom - Discrete Lattice Gauge Theories, Emergence and Quantum Simulation · May 9, 2022 - May 13, 2022 International Meeting or Conference Max Plank Institute, Munich, Germany Invited talk at the meeting

Building our Universe with Qubits - Physics Colloquium · March 24, 2022 Keynote/Named Lecture Lehigh University, Lehigh, Pennsylvania Invited Physics Colloquium

Four-Fermion Field Theories on the Lattice - Theoretical Seminar · September 13, 2021 Invited Talk Iowa University, Online Virtual Talk Invited online talk

Conformal Dimensions in the Sub-Leading Large Charge Sector of the O(4) model - QM Systems at Large Quantum Numbers · August 30, 2021 International Meeting or Conference Bern University, Online Attendance Invited online talk

Interacting Massless Dirac Fermions with Spin-Charge Flip Symmetry - Relativistic Fermions in Flatland: Theory and Applications · July 5, 2021 - July 9, 2021 Instructional Course, Workshop, or Symposium ECT*, Trento Italy, Online Attendance Online Attendance

Subleading conformal dimensions using qubit regularization of the O(4) model - International Symposium on Lattice Field Theory · June 26, 2021 - June 30, 2021 International Meeting or Conference Massachusetts Institute of Technology, Online Zoom Conference Online participation

Qubit Regularization: Large Charge CFTs and Asymptotic Freedom - Theoretical Seminar · June 10, 2021 Invited Talk Bern University, Invited Virtual Talk Invited virtual talk

Qubit Regularization and Quantum Links - Quantum Similation for Strong Interactions · April 8, 2021 National Scientific Meeting Institute for Nuclear Theory, University of Washington, Seattle, Online Virtual Talk Invited talk along with Uwe-Jens Wiese

Qubit Regularization of Asymptotic Freedom - Non-perturbative and numerical approaches to quantum gravity, string theory and holography · January 18, 2021 Instructional Course, Workshop, or Symposium International Center for Theoretical Sciences, Online Virtual Talk Online talk at the workshop

Qubit Regularization of Asymptotic Freedom - Theoretical Seminar · January 14, 2021 Invited Talk Saha Institute for Nuclear Physics, Online Virtual Talk Online talk

Qubit Regularization of Asymptotic Freedom - Annual Fall DNP of the APS · October 29, 2020 - November 1, 2020 International Meeting or Conference APS, Virtual

Qubit Regularization of Quantum Field Theories - Nuclear Theory Seminar · October 15, 2020 - October 15, 2020 Other Duke University

Fermion Bag Methods · January 27, 2020 - February 1, 2020 Lecture Three lectures at the winter school on "Algorithms for Lattice Gauge Theories and Quantum Spin Systems" held in Kolkata India.

Qubit Regularization of Quantum Field Theories - Invited Theoretical Physics Seminar · September 6, 2019 Invited Talk Brookhaven National Laboratory, Upton, NY Motivated by the desire to study quantum field theories on a quantum computer, we propose a new type of regularization of quantum field theories where in addition to the usual lattice regularization, quantum field theories are constructed with a finite dimensional Hilbert space per lattice site. This is particularly relevant for studying bosonic field theories using a quantum computer since traditional lattice regularization assumes an infinite dimensional Hilbert space per lattice site and hence difficult to formulate on a quantum computer. Here we show that a two qubit model is sufficient to recover the 3d Wilson-Fisher fixed point and the 4d Gaussian fixed point of the O(3) sigma model. On the other hand in 2d, our qubit model does not seem to have a continuum limit although we have to go to study large lattices to establish this fact. We discuss modifications of our model that could perhaps yield a continuum limit.

Monte Carlo calculations of conformal dimensions of large charge operators - Invited talk at the program on Quantum Mechanical Systems at Large Charge · August 26, 2019 - September 20, 2019 Invited Talk Simons Center for Geometry and Physics, Stony Brook, NY Recently it was proposed that conformal dimensions of certain large charge operators satisfy a simple relation with unknown coefficients. In this talk we explain our efforts to test this proposal and compute the unkown coefficients using Monte Carlo calculations. We focus on CFTs that arise at the O(2) and O(4) Wilson-Fisher fixed points as test cases. Since traditional Monte Carlo methods suffer from a severe signal-to-noise ratio problem in the large charge sectors, we use worldline formulations. In the O(2) case we show that the proposed large charge expansion works very well even up to the smallest charge. In the O(4) case, the charged sectors are labeled by the two SU(2) representations $(j_L,j_R)$. Here we introduce and study a drastically simplified alternate model, which we refer to as a "qubit model". We find that the $(j,j)$ sector continues to show excellent agreement with the proposed large charge expansion, again up to small values of $j$. We also present preliminary results on the behavior of the subleading $(j,j-1)$ sector.

Building our Universe with Qubits - Physics Colloquium · July 31, 2019 Invited Talk Tata Institute for Fundamental Research, Hyderabad, India The success of the standard model of particle physics is based on the quantum theory of fields where the basic assumptions lead to mathematical infinities. While the theory of renormalization helps us understand why these infinities are in fact harmless, they are still difficult to handle computationally, especially within the strongly interacting sector that describes nuclear physics. Recent effort to overcome these computational bottlenecks using a quantum computer is motivating us to think of new ways to build our universe with qubits. I will discuss the basic ideas and some recent results that suggests that this may indeed be possible.

Conformal dimensions using a large charge expansion - Theoretical Physics Colloquium · July 23, 2019 Invited Talk Tata Institute for Fundamental Research, Mumbai, India Conformal field theories (CFTs) are described by a set of dimensionless numbers referred to as conformal dimensions, which are difficult to compute. Recently it was proposed that conformal dimensions of certain large charge operators satisfy a simple relation with unknown coefficients. In this talk we explain our efforts to test this proposal and compute the unkown coefficients using Monte Carlo calculations. We focus on CFTs that arise at the O(2) and O(4) Wilson-Fisher fixed points as test cases. Since traditional Monte Carlo methods suffer from a severe signal-to-noise ratio problem in the large charge sectors, we use worldline formulations. In the O(2) case we show that the large charge expansion works very well even up to the smallest charge. In the O(4) case, the charged sectors are labeled by the two SU(2) representations $(j_L,j_R)$. Here we introduce and study a drastically simplified alternate model, which we refer to as a "qubit model". We find that the $(j,j)$ sector continues to show excellent agreement with the large charge expansion, again up to small values of $j$. We also present preliminary results on the behavior of the subleading $(j,j-1)$ sector, which however suggests a less satisfying scenario.

Qubit Regularization of Quantum Field Theories - Invited "Free Meson Seminar" · July 18, 2019 Invited Talk Tata Institute for Fundamental Research, Mumbai, India Motivated by the desire to study quantum field theories on a quantum computer, we propose a new type of regularization of quantum field theories where in addition to the usual lattice regularization, quantum field theories are constructed with a finite dimensional Hilbert space per lattice site. This is particularly relevant for studying bosonic field theories using a quantum computer since traditional lattice regularization assumes an infinite dimensional Hilbert space per lattice site and hence difficult to formulate on a quantum computer. Here we show that a two qubit model is sufficient to recover the 3d Wilson-Fisher fixed point and the 4d Gaussian fixed point of the O(3) sigma model. On the other hand in 2d, the continuum limit of our qubit model is difficult to establish because of asymptotic freedom. Even, if it exists it seems to belong to a different universality class.

Monte Carlo calculations of conformal dimensions of large charge operators - Invited Physics Seminar · July 5, 2019 Invited Talk Indian Institute of Science, Bengaluru, India We test the recent proposal for computing conformal dimensions using a large charge expansion using Monte Carlo methods. We focus on the O(2) and the O(4) Wilson-Fisher fixed points as test cases. Unfortunately, traditional Monte Carlo methods suffer from a severe signal-to-noise ratio problem in the large charge sectors. To overcome this bottleneck we use worldline formulations. In the O(2) case we show that conformal dimensions of charge $q$ operators obey a simple formula predicted by the large charge expansion. In the O(4) case, the charged sectors are labeled by the two SU(2) representations $(j_L,j_R)$. Since the traditional model continues to be difficult to explore in the large $(j_L, j_R)$ sectors, we study a drastically simplified alternate model, which we refer to as a "qubit regularization” of the original model. Such simpler formulations of scalar quantum field theories have become interesting recently from the perspective of quantum computing. Here we again find that the $(j,j)$ sector continues to show excellent agreement with the predicted large charge expansion up to small values of $j$. However, preliminary results on the behavior of the next subleading sector $(j,j-1)$ suggests a less satisfying scenario.

Monte Carlo calculations of conformal dimensions of large charge operators - Invited Physics Seminar · July 4, 2019 Invited Talk International Center for Theoretical Studies, Bengaluru, India In order to test the recent proposal for computing conformal dimensions using a large charge expansion, we explore Monte Carlo methods to compute them. We focus on the O(2) and the O(4) Wilson-Fisher fixed points as test cases. Unfortunately, traditional Monte Carlo methods suffer from a severe signal-to-noise ratio problem in the large charge sectors. To overcome this bottleneck we use worldline formulations. In the O(2) case we show that conformal dimensions of charge $q$ operators obey a simple formula predicted by the large charge expansion. In the O(4) case, the charged sectors are labeled by the two SU(2) representations $(j_L,j_R)$. Since the traditional model continues to be difficult to explore in the large $(j_L, j_R)$ sectors, we study a drastically simplified alternate model, which we refer to as a "qubit" formulation. Such simpler formulations of quantum field theories have become interesting recently from the perspective of quantum computing. Here we find that while the $(j,j)$ sector continues to show excellent agreement with the predicted large charge expansion up to small values of $j$, the behavior of the next subleading sector $(j,j-1)$ is far from satisfying.

Conformal dimensions in the large charge sectors at the Wilson-Fisher fixed point using qubit formulations - Invited Condensed Matter Seminar · May 28, 2019 Invited Talk Perimeter Institute, Waterloo, Canada Using Monte Carlo methods we explore how well does the recent proposal for computing conformal dimensions, using a large charge expansion, work. We focus on the O(2) and the O(4) Wilson-Fisher fixed points as test cases. Since the traditional Monte Carlo approach suffers from a severe signal-to-noise ratio problem in the large charge sectors, we use worldline formulations that eliminate such problems. In particular we argue that the O(4) model can be simplified drastically by studying what we refer to as a "qubit" formulation. Such simpler formulations of quantum field theories have become interesting recently from the perspective of quantum computing. Using our studies we confirm that the conformal dimensions of both conformal field theories with O(2) and O(4) symmetries obey a simple formula predicted by the large charge expansion. We also compute the two leading universal low energy constants in both cases , that play an important role in the large charge expansion.

Conformal dimensions in large charge sectors using “qubit” formulations - Invited talk at the annual workshop on Lattice for Beyond the Standard Model Physics · May 2, 2019 - May 3, 2019 Invited Talk Syracuse University, Syracuse, NY

Emergence of Gauss’ Law in a Z2 Lattice Gauge Theory - Invited Quantum Many Body Physics Seminar · April 2, 2019 Invited Talk Simons Flatiron Institute, New York, NY

Qubit formulations of QFT - Invited talk at the meeting on Quantum Computing and Information for Nuclear Physics · January 23, 2019 - January 25, 2019 National Scientific Meeting Nuclear Physics Quantum Computing Collaboration, Santa Fe, NM

Fermionic Quantum Critical Points - Invited Physics Colloquium · October 25, 2018 Invited Talk UNC Wilmington, Wilmington, NC

Fermion Bag Approach to Fermion Sign Problems · December 21, 2013 Lecture workshop on "Advances in Quantum Monte Carlo techniques in Quantum Many Body Physics" at the Institute for Nuclear Theory, Seattle Washington

New approaches to finite density lattice field theory · December 20, 2013 Lecture Schladming Winter School, Schladming, Austria

Lattice 2012 · December 14, 2012 Lecture Cairns, Australia

New approaches to Strongly Correlated Fermions · November 30, 2012 Lecture Jena, Germany

Fermion Bag Approach to Lattice Field Theories · October 15, 2012 Lecture Syracuse, New York

Fermion-Bag solutions to Sign Problems · September 21, 2012 Lecture Regensburg Germany

Fermion-Bag solutions to some unsolved sign problems · August 1, 2012 Lecture KITPC, Beijing, China

Fermion Bag Approach to Sign Problems · July 18, 2012 Lecture Chennai, India

Solutions to some unsolved sign problems in strongly correlated lattice fermion systems · July 17, 2012 Lecture Chennai, India

Solutions to some unsolved sign problems in strongly correlated lattice fermion systems · July 11, 2012 Lecture Kolkutta, India

New solutions to some old sign problems · June 5, 2012 Lecture

Fermion-bag approach to four-fermion lattice field theories · June 28, 2011 Lecture Theoretical physics seminar, Indian Institute of Science, Bangalore, India

Generalized Fermion-bag approach to four-fermion lattice field theories · June 3, 2011 Lecture Theoretical physics seminar, ETH, Zurich Switzerland.

Fermion bag approach to four-fermion lattice field theories · May 30, 2011 Lecture Theoretical physics seminar, CERN, Geneva Switzerland

Fermion bag approach to four-fermion lattice field theories · May 27, 2011 Lecture Theoretical physics seminar, Bern University, Bern, Switzerland.

World Line approach to Lattice Fermions · May 26, 2011 Lecture Journal Club Talk, Bern University, Bern, Switzerland.

The Fermion Bag Approach · February 2, 2011 Lecture Theoretical Physics Seminar, University of Virginia, Charlottesville

Quantum Mechanics and the Computational Challenge for the 21st Century · January 24, 2011 Lecture Physics Colloquiium, North Carolina State University, Raleigh North Carolina

Anomaly and the QCD Critical Point : A study in a strongly correlated system · July 4, 2010 Lecture Tata Insitute of Fundamental Research

Quantum Mechanics and the Computational Challenges for the 21st Century · June 30, 2009 Lecture Tata Institute of Fundamental Research, Mumbai, India

Sigma-Resonance and Chiral Perturbation Theory · May 7, 2009 Lecture Saha Institute, Kolkutta India

World-line approach to lattice field theories · May 6, 2009 Lecture Indian Institute for the the Advancement and Cultivation of Science, Kolkutta, India

World-line approach to sign problems · March 4, 2009 Lecture

World-line approach to lattice field theories · February 26, 2009 Lecture University of Graz, Austria

World-line approach to lattice field theories · February 23, 2009 Lecture University of Swansea, UK

Sigma-resonance and convergence of chiral perturbation theory · January 13, 2009 Lecture International workshop on Frontier Problems in Strong Interaction Physics, PPISR, Bangalore, India

Monte Carlo Methods in Lattice Field Theories · December 12, 2008 Lecture Twelve invited lectures for students and faculty, at the Tata Institute for fundamental Research, Mumbai, India

Fun with four fermion models · December 12, 2008 Lecture Invited talk at the "Indian Condensed Matter Workshop" held at Mahabaleshwar, India

LATTICE 2008 · December 12, 2008 Lecture Williamsburg Virginia, USA

Fun with four-fermion Models · December 12, 2008 Lecture Indian Condensed Matter Workshop, Mahabaleshwar, India

A new approach to computational quantum field theory · December 12, 2008 Lecture Plenary talk at ``The XXVI International Symposium on Lattice Field theory'', held at Williamsburg Virginia, USA

APS March Meeting · December 12, 2008 Lecture New Orleans, Louisiana USA

Service to the Profession

Journal Paper Review for Physical Review B · June 2025 Editorial Activities American Physical Society, Online

Proposal Reviewer for Department of Energy · May 2025 Consulting Department of Energy, Online

Journal Paper Review for Computer Physics Communications · April 2025 Editorial Activities Science Direct, Online

Journal Paper Review for Physical Review B · March 2025 Editorial Activities American Physical Society, Online

Proposal Reviewer · February 2025 Committee Service Department of Energy, Online

Faculty Productivity Review · December 2023 Consulting South Africa Research National Foundation

PhD Dissertation Reviewer of doctoral student · January 2023 Committee Service Indian Institute of Science Education Research, Mohali, India

Co-Organizer, with Emilie Huffman (Chair) and Ribhi Kaul, Quantum Criticality: Gauge Fields and Matter · May 16, 2022 - May 20, 2022 Administration Perimeter Institite, Waterloo, Canada Ever more efficient numerical methods, such as quantum Monte Carlo sampling of expanded classes of known sign-problem-free models and tensor network methods, have enabled unbiased studies of a number of exotic phases and continuous phase transitions, such as those involving topological phases and emergent gauge fields. The phenomena of interest often arise in simple looking designer models, which are attractive to a wide variety of theorists, including those who study condensed matter, high energy physics, and quantum information. This broad appeal stems from the fact that these models can be viewed as interesting models of materials, as regularizations of strongly coupled quantum field theories, or as playgrounds to study highly entangled quantum systems.

This interdisciplinary workshop thus aims to bring together researchers with the goal of facilitating an exchange of ideas for understanding these models using diverse numerical methods and from the field-theoretic point of view.

Co-Chair, Organizing Committee, Diagrammatic Mote Carlo methods in Nuclear, Particle and Condensed Matter Physics. · September 18, 2017 - September 29, 2017 Administration Mainz Institute for Theoretical Physics (MITP)., MITP, Mainz Germany

Chair, Organizing Committee, International Workshop on the Sign Problem in QCD and Beyond · March 20, 2017 - March 24, 2017 Administration Institute for Nuclear Theory, Seattle WA, Institute for Nuclear Theory, Seattle WA

Chair, Organizing Committee, Diagrammatic Mote Carlo methods in Nuclear, Particle and Condensed Matter Physics. · October 5, 2015 - October 9, 2015 Administration ECT* Trento, Trento Italy

Organizer, Understanding Strongly Coupled Systems in High Energy and Condensed Matter Physics · May 24, 2015 - June 13, 2015 Administration Aspen Center for Physics, Aspen Colorado Understanding strongly coupled quantum systems has become a unifying theme for both condensed matter and particle physcists. The possibility of finding that Higgs could be a composite particle that emerges from a new strongly interacting sector is encouraging particle physicists to explore a variety of gauge theories. At the same time the discovery of many materials that show strong correlation effects is forcing condensed matter physicists to look for explanations that go beyond the standard paradigms, including emergent gauge fields, non-Fermi liquids and topological phases. Interestingly, the challenges that the two communities face are quite similar and the goal of the workshop is to bring together experts from both communities to facilitate discussion. Topics of common interest include phase structure and dynamics in strongly coupled systems, especially in the vicinity of quantum critical points. Questions related to these topics appear in the study of quantum antiferromagnets, superconductors, metal-insulator transitions, dense nuclear matter, conformal and near conformal gauge theories, holographic models, and topological field theories. Through the exchange of ideas involving theoretical insights and advances in computational algorithms, and by exploring the possibility of developing quantum simulators to study the underlying problems, the hope is to initiate future collaborations between the two communities and to encourage younger scientists to see their work within a broader framework.

Referee : Physica A · 2013 Editorial Activities

Reviewer for Swiss National Foundation Grant Proposals · December 15, 2012 Committee Service

Reviewer for FONDECYT (Chile, NSF) · November 2012 Committee Service

Reviewer for European Research Council Grant Proposal · 2011 Committee Service

Referee : International Journal for Theoretical Physics · 2010 Editorial Activities

Co-Chair : ECT* Workshop titled "Sign Problems and Complex Actions" · March 2, 2009 Administration Trento Italy

Referee : Journal of Physics · 2009 Editorial Activities

Organizers (Thomas Schaefer (chair), Dean Lee and Shailesh Chandrasekharan) : Extreme QCD 2008 · December 12, 2008 Administration North Carolina State University

Journal Referee, Physical Review Letters, Physical Review D, Physical Review B · 1997 - 2023 Consulting American Physical Society

Service to Duke

Chair, Executive Committee of Graduate Faculty · July 2014 - June 2015 Administration Graduate School

Executive Committee of Graduate Faculty (University) · July 2013 - June 2015 Committee Service Graduate School

Leadership & Clinical Positions

Chair, Executive Committee of Graduate Faculty, from July 2014 to June 2015

Academic & Administrative Activities

Chair of the Core Course Committee (July - Dec, 2019).
Chair of the Graduate Curriculum Committee (July - Dec, 2019).
Chair of the News and Web Committee (Sep 2018 - Present).

Duke Initiatives

PhD Student Mentor Post-Doc Mentor Undergraduate Student Mentor