Connecting the SYK dots

TL;DR

This paper investigates a metal-insulator transition in a granular array of SYK quantum dots, emphasizing the role of Coulomb interactions and charge fluctuations in altering conductivity and density of states.

Contribution

It extends previous SYK models by incorporating Coulomb interactions and analyzes the resulting effects on charge transport and electronic properties during the transition.

Findings

Conductivity shows significant change at the transition point.

Density of states exhibits marked behavioral shifts near the transition.

Transition occurs when inter-site tunneling matches the Coulomb energy.

Abstract

We study a putative (strange) metal-to-insulator transition in a granular array of the Sachdev-Ye-Kitaev (SYK) quantum dots, each occupied by a large number N>>1 of charge-carrying fermions. Extending the previous studies we complement the SYK couplings by the physically relevant Coulomb interactions and focus on the effects of charge fluctuations, evaluating the conductivity and density of states. The latter were found to demonstrate marked changes of behavior when the effective inter-site tunneling becomes comparable to the renormalized Coulomb energy, thus signifying the transition in question.