Quantum noise of electron-phonon heat current

TL;DR

This paper investigates the quantum noise in electron-phonon heat current, revealing persistent fluctuations at finite frequencies even at zero temperature, with implications for sensitive calorimetry and photon detection.

Contribution

It provides a detailed analysis of heat current fluctuations at finite frequencies, extending understanding of quantum noise in electron-phonon interactions at low temperatures.

Findings

Heat current noise persists at zero temperature.

Equilibrium results align with the fluctuation-dissipation theorem.

Implications for microwave-photon detection and calorimetry.

Abstract

We analyze heat current fluctuations between electrons and phonons in a metal. In equilibrium we recover the standard result consistent with the fluctuation-dissipation theorem. Here we show that heat current noise at finite frequencies, remains non-vanishing down to zero temperature. We briefly discuss the impact of electron-phonon heat current fluctuations on calorimetry, in particular in the regime of single microwave-photon detection.