Quantum criticality out of equilibrium in the pseudogap Kondo model

Abstract

We theoretically investigate the non-equilibrium quantum phase transition in a generic setup: the pseudogap Kondo model where a quantum dot couples to two-left (L) and right (R)-voltage-biased fermionic leads with power-law density of states (DOS) with respect to their Fermi levels μ_L/R, ρ_c,L(R) (ω) \propto |ω - μ_L(R) |r, and 0 < r < 1. In equilibrium (zero bias voltage) and for 0 < r < 1/2, with increasing Kondo correlations, in the presence of particle-hole symmetry this model exhibits a quantum phase transition from a unscreened local moment (LM) phase to the Kondo phase. Via a controlled frequency-dependent renormalization group (RG) approach, we compute analytically and numerically the non-equilibrium conductance, conduction electron T-matrix and local spin susceptibility at finite bias voltages near criticality. The current-induced decoherence shows distinct nonequilibrium scaling, leading to new universal non-equilibrium quantum critical behaviors in the above observables. Relevance of our results for the experiments is discussed.

4.1 pages, 2 figures

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Cited by in corpus (5)

• Pseudogap Anderson impurity model out of equilibrium: A master equation tensor network approach
• Steady-state dynamics and effective temperatures of quantum criticality in an open system
• Mixed-order symmetry-breaking quantum phase transition far from equilibrium
• Transport properties for a quantum dot coupled to normal leads with pseudogap
• Quantum criticality of the two-channel pseudogap Anderson model: Universal scaling in linear and non-linear conductance