Noise signatures of a charged Sachdev-Ye-Kitaev dot in mesoscopic transport

TL;DR

This paper explores quantum noise in a mesoscopic charged SYK quantum dot, identifying unique signatures and developing a universal framework for experimental detection of SYK and non-Fermi-liquid physics.

Contribution

It introduces a linear response theory for noise in SYK dots, revealing universal constants and scaling laws that distinguish SYK physics from other regimes.

Findings

Noise signatures serve as markers of SYK physics in experiments.

Universal constants connect noise coefficients and characterize Coulomb blockade.

Scaling of noise coefficients with temperature reveals non-Fermi-liquid behavior.

Abstract

We investigate quantum noise in a mesoscopic quantum dot serving as a realization of the charged Sachdev-Ye-Kitaev (SYK) model weakly coupled to a fermionic lead via a tunnel contact. We find noise signatures under voltage and temperature biases that can serve as clear markers of the SYK physics in experiments with related setups. We develop a linear response theory that treats all types of noise on the same footing and generalizes a concept of transport coefficients for charge and heat currents, as well as relations between them, to equilibrium noise power. Within this theory, we find characteristic scaling of the noise coefficients with temperature in all regimes that can be relevant for experimental realizations of the SYK dots, find a set of universal constants, with their values being unique to the SYK physics, that connect these coefficients, and characterize noise manifestations of the Coulomb blockade. Beyond SYK systems, these results may serve as a general framework for identification of non-Fermi-liquid signatures in mesoscopic transport and provide additional observables for experiments on thermoelectric phenomena.