The noise spectra of a biased quantum dot

TL;DR

This paper calculates the noise spectra in a biased quantum dot, revealing how asymmetry and temperature affect current and charge fluctuations, with distinctive step-like features and dips in the spectra.

Contribution

It provides a detailed analysis of the noise spectra in a biased quantum dot, highlighting the effects of coupling asymmetry and finite temperature on spectral features.

Findings

Spectra show 2 or 4 steps depending on the level position.

Low-frequency shot noise exhibits dips and peaks.

Features persist at finite temperatures with some smearing.

Abstract

The noise spectra associated with correlations of the current through a single level quantum dot, and with the charge fluctuations on the dot, are calculated for a finite bias voltage. The results turn out to be sensitive to the asymmetry of the dot's coupling to the two leads. At zero temperature, both spectra exhibit two or four steps (as a function of the frequency), depending on whether the resonant level lies outside or within the range between the chemical potentials on the two leads. In addition, the low frequency shot-noise exhibits dips in the charge noise and dips, peaks, and discontinuities in the derivative of the current noise. In spite of some smearing, several of these features persist at finite temperatures, where a dip can also turn into a peak.