Heat Coulomb Blockade of One Ballistic Channel

TL;DR

This paper reports the experimental observation of Coulomb blockade effects on heat flow in a small metallic quantum circuit, revealing a fundamental difference between thermal and electrical conductance at the quantum level.

Contribution

It demonstrates the thermal Coulomb blockade in a ballistic channel, showing a universal suppression of heat conductance without affecting electrical conductance, highlighting new quantum thermal transport phenomena.

Findings

Observation of heat Coulomb blockade beyond Wiedemann-Franz law

Universal suppression of one quantum of heat conductance

No suppression of electrical conductance in the same conditions

Abstract

Quantum mechanics and Coulomb interaction dictate the behavior of small circuits. The thermal implications cover fundamental topics from quantum control of heat to quantum thermodynamics, with prospects of novel thermal machines and an ineluctably growing influence on nanocircuit engineering. Experimentally, the rare observations thus far include the universal thermal conductance quantum and heat interferometry. However, evidences for many-body thermal effects paving the way to markedly different heat and electrical behaviors in quantum circuits remain wanting. Here we report on the observation of the Coulomb blockade of electronic heat flow from a small metallic circuit node, beyond the widespread Wiedemann-Franz law paradigm. We demonstrate this thermal many-body phenomenon for perfect (ballistic) conduction channels to the node, where it amounts to the universal suppression of precisely one quantum of conductance for the transport of heat, but none for electricity. The inter-channel correlations that give rise to such selective heat current reduction emerge from local charge conservation, in the floating node over the full thermal frequency range ($\lesssim$temperature$\times k_\mathrm{B}/h$). This observation establishes the different nature of the quantum laws for thermal transport in nanocircuits.