Non-Equilibrium Kondo Model with Voltage Bias in a Magnetic Field

TL;DR

This paper develops a 2-loop scaling framework for a Kondo quantum dot under equilibrium and non-equilibrium conditions, accounting for decoherence effects and analyzing key physical quantities.

Contribution

It introduces a comprehensive flow equation approach to study non-equilibrium Kondo physics, including voltage bias and magnetic field effects, with detailed calculations of correlation functions and magnetization.

Findings

Observation of Kondo splitting under voltage bias

Enhanced logarithmic corrections in non-equilibrium

Decoherence effects significantly influence Kondo behavior

Abstract

We derive a consistent 2-loop scaling picture for a Kondo dot in both equilibrium and non-equilibrium situations using the flow equation method. Our analysis incorporates the important decoherence effects from both thermal and non-equilibrium noise in a common setting. We calculate the spin-spin correlation function, the T-matrix, and the magnetization as functions of applied magnetic field, dc-voltage bias and temperature. In all these quantities we observe characteristic non-equilibrium features for a nonvanishing external voltage bias like Kondo splitting and strongly enhanced logarithmic corrections.