Connecting the SYK dots

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.