Analytical Continuation Approaches to Electronic Transport: The Resonant Level Model

TL;DR

This paper compares analytical continuation methods, ASM and MaxEnt, for calculating electronic transport properties in a resonant level model, finding MaxEnt to be more accurate across various conditions.

Contribution

The study evaluates and compares the effectiveness of ASM and MaxEnt methods in extracting spectral functions from imaginary time data in a resonant level model.

Findings

MaxEnt yields more accurate spectral results than ASM.

Both methods are applied across a wide range of temperatures and voltages.

Results are validated against exact solutions.

Abstract

The analytical continuation average spectrum method (ASM) and maximum entropy (MaxEnt) method are applied to the dynamic response of a noninteracting resonant level model within the framework of the Kubo formula for electric conductivity. The frequency dependent conductivity is inferred from the imaginary time current-current correlation function for a wide range of temperatures, gate voltages and spectral densities representing the leads, and compared with exact results. We find that the MaxEnt provides more accurate results compared to the ASM over the full spectral range.