A numerical renormalization group approach to non-equilibrium Green functions for quantum impurity models
نویسنده
چکیده
We present a method for the calculation of dynamical correlation functions of quantum impurity systems out of equilibrium using Wilson’s numerical renormalization group (NRG). Our formulation is based on a complete basis set of the Wilson chain and embeds the recently derived algorithm for equilibrium spectral functions. Our method fulfils the spectral weight conserving sum-rule exactly by construction. A local Coulomb repulsion U > 0 is switched on at t = 0, and the asymptotic steady-state spectral functions are obtained for various values of U as well as magnetic field strength H and temperature T . These benchmark tests show excellent agreement between the time-evolved and the directly calculated equilibrium NRG spectra for finite U . This method could be used for calculating steady-state non-equilibrium spectral functions at finite bias through interacting nanodevices. (Some figures in this article are in colour only in the electronic version)
منابع مشابه
A Numerical Renormalization Group approach to Non-Equilibrium Green’s Functions for Quantum Impurity Models
We present a method for the calculation of dynamical correlation functions of quantum impurity systems out of equilibrium using Wilson’s numerical renormalization group. Our formulation is based on a complete basis set of the Wilson chain and embeds the recently derived algorithm for equilibrium spectral functions. Our method fulfills the spectral weight conserving sum-rule exactly by construct...
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