Quantum thermal transport in the charged Sachdev-Ye-Kitaev model: Thermoelectric Coulomb blockade

TL;DR

This paper develops a microscopic theory for quantum thermoelectric and heat transport in the charged Sachdev-Ye-Kitaev model, revealing how elastic and inelastic processes influence transport coefficients at low temperatures.

Contribution

It introduces a detailed analysis of charge and heat transport in a charged SYK model setup, highlighting the roles of elastic and inelastic processes and the suppression of thermoelectric effects.

Findings

Both electric and thermal conductance follow a power law in temperature.

Thermoelectric coefficients are exponentially suppressed at low temperatures.

Inelastic processes dominate transport at temperatures below the charging energy.

Abstract

We present a microscopic theory for quantum thermoelectric and heat transport in the Schwarzian regime of the Sachdev-Ye-Kitaev (SYK) model. As a charged fermion realization of the SYK model in nanostructures we assume a setup based on a quantum dot connected to the charge reservoirs through weak tunnel barriers. We analyze particle-hole symmetry breaking effects crucial for both Seebeck and Peltier coefficients. We show that the quantum charge and heat transport at low temperatures are defined by the interplay between elastic and inelastic processes such that the inelastic processes provide a leading contribution to the transport coefficients at the temperatures that are smaller compared to the charging energy. We demonstrate that both electric and thermal conductance obey a power law in temperature behavior, while thermoelectric, Seebeck, and Peltier coefficients are exponentially suppressed. This represents selective suppression of only nondiagonal transport coefficients. We discuss the validity of the Kelvin formula in the presence of a strong Coulomb blockade.