Electronic heat current fluctuations in a quantum dot

TL;DR

This paper investigates the fluctuations of heat current in a quantum dot system at finite frequency, voltage, and temperature, revealing how asymmetry and out-of-equilibrium conditions influence heat noise and its relation to radiative spectra.

Contribution

It provides a detailed theoretical analysis of non-symmetrized heat noise in quantum dots using nonequilibrium Green functions, including effects of coupling asymmetry and out-of-equilibrium conditions.

Findings

Heat noise is expressed as an energy integral with four contributions.

Asymmetry in reservoir coupling affects heat noise characteristics.

In high transmission, heat noise relates to the radiative power spectrum, resembling an out-of-equilibrium Planck's law.

Abstract

The fluctuations of the heat current in a quantum dot coupled to electron reservoirs are calculated at finite frequency, voltage and temperature using the nonequilibrium Green function technique. The non-symmetrized heat noise is expressed as an integral on energy containing four contributions, each of which includes transmission amplitudes, electron-hole pair distribution functions and energy difference factors. The effect of the asymmetry of the couplings between the quantum dot and the reservoirs is studied. Features of the heat noise are highlighted and discussed for an equilibrium and an out-of-equilibrium quantum dot. In the latter case and within the high transmission limit, the heat noise is closely related to the radiative power spectrum, leading to an out-of-equilibrium Planck's law. Proposals for the measurement of the heat noise are discussed.