Universal Nonequilibrium I-V Curve at an Interacting Impurity Quantum Critical Point

Journal Article (Academic article)

Nonequilibrium properties of correlated quantum matter are being intensively investigated because of the rich interplay between external driving and the many-body correlations. Of particular interest is the nonequilibrium behavior near a quantum critical point (QCP), where the system is delicately balanced between different ground states. We present both an analytical calculation of the nonequilibrium steady-state current in a critical system and experimental results to which the theory is compared. The system is a quantum dot coupled to resistive leads: a spinless resonant level interacting with an ohmic dissipative environment. A two-channel Kondo-like QCP occurs when the level is on resonance and symmetrically coupled to the leads, conditions achieved by fine tuning using electrostatic gates. We calculate and measure the nonlinear current as a function of bias (I−V curve) at the critical values of the gate voltages corresponding to the QCP. The quantitative agreement between the experimental data and the theory, with no fitting parameter, is excellent. As our system is fully accessible to both theory and experiment, it provides an ideal setting for addressing nonequilibrium phenomena in correlated quantum matter.

Full Text

Duke Authors

Cited Authors

  • Zhang, G; Chung, C-H; Ke, CT; Lin, C-Y; Mebrahtu, H; Smirnov, AI; Finkelstein, G; Baranger, HU

Published Date

  • February 11, 2021

Published In

Volume / Issue

  • 3 /


  • 013136

Start / End Page

  • 013136 - 013136

Published By


  • 15

International Standard Serial Number (ISSN)

  • 2643-1564

Digital Object Identifier (DOI)

  • 10.1103/PhysRevResearch.3.013136