Equilibrium finite-frequency noise of an interacting mesoscopic capacitor studied in time-dependent density functional theory

TL;DR

This paper uses time-dependent density functional theory to compute the equilibrium noise spectrum of an interacting mesoscopic capacitor, revealing the method's accuracy at frequencies below the reservoir temperature.

Contribution

It demonstrates the effectiveness of a recently developed exchange-correlation potential in predicting finite-frequency noise in mesoscopic systems.

Findings

Excellent agreement with perturbation theory below reservoir temperature

Validates the use of time-nonlocal exchange-correlation potentials in TDDFT

Provides insights into frequency-dependent noise behavior in quantum dots

Abstract

We calculate the frequency-dependent equilibrium noise of a mesoscopic capacitor in time-dependent density functional theory (TDDFT). The capacitor is modeled as a single-level quantum dot with on-site Coulomb interaction and tunnel coupling to a nearby reservoir. The noise spectra are derived from linear-response conductances via the fluctuation-dissipation theorem. Thereby, we analyze the performance of a recently derived exchange-correlation potential with time-nonlocal density dependence in the finite-frequency linear-response regime. We compare our TDDFT noise spectra with real-time perturbation theory and find excellent agreement for noise frequencies below the reservoir temperature.