Thermalization and low-temperature entropy across non-Fermi liquid to Fermi liquid transitions

In recent years, a zero-dimensional solvable model of interacting fermions, namely Sachdve-Ye-Kitaev (SYK) model, has emerged as a new paradigm to describe non-Fermi iquid metals as well as thermalization and many-body quantum chaos in interacting systems. In the first part of the talk, I will discuss thermalization, after sudden and slow quenches, in a zero-dimensional model having a quantum phase transition from a SYK non-Fermi liquid (NFL) to a Fermi liquid (FL). I will also discuss the implications of large zero-temperature entropy of the NFL state on non-equilibrium dynamics. The model has SYK fermions coupled to non-interacting lead fermions and can be realized in a graphene flake connected to external leads. In the second part (if time permits), I will discuss a higher-dimensional generalization of SYK model which gives rise to NFL states that are distinct from the zero-dimensional SYK NFL in terms of many-body chaos and low- temperature entropy.

References:
1. A. Haldar, P. Haldar, I. Mandal, S. Banerjee. arXiv:1903.09652 (2019).
2. A. Haldar, S. Banerjee, V. B. Shenoy. Phys. Rev. B (Rapid) 97, 241106 (2018).
3. S. Banerjee and E. Altman. Phys. Rev. B 95, 134302 (2017).