Quantum tunneling dynamics in a complex-valued Sachdev-Ye-Kitaev model quench-coupled to a cool bath

TL;DR

This paper investigates the tunneling dynamics of a complex SYK model coupled to a cold bath, revealing distinct temperature scaling behaviors in the discharging process that differentiate non-Fermi liquid states from Fermi liquids.

Contribution

It demonstrates how the discharging dynamics and tunneling current in a complex SYK model exhibit unique temperature-dependent scaling, highlighting non-Fermi liquid characteristics.

Findings

Tunneling current's half-life scales linearly with temperature in SYK non-Fermi liquids.

In Fermi liquids, the half-life scales as the square of temperature.

Distinct temperature scaling behaviors serve as signatures of non-Fermi liquid states.

Abstract

The Sachdev-Ye-Kitaev (SYK) model describes interacting fermionic zero modes in zero spatial dimensions, e.g. quantum dot, with interactions strong enough to completely washout quasiparticle excitations in the infrared. In this paper, we consider the complex-valued SYK model at initial temperature $T$ and chemical potential $\mu$ coupled to a large reservoir by a quench at time $t=0$. The reservoir is kept at zero temperature and charge neutrality. We find that the dynamics of the discharging process of the SYK quantum dot reveals a distinctive characteristic of the SYK non-Fermi liquid (nFl) state. In particular, we focus on the tunneling current induced by the quench. We show that the temperature dependent contribution to the current's half-life scales linearly in $T$ at low temperatures for the SYK nFl state, while for the Fermi liquid it scales as $T^2$.