Subsystem R\'enyi Entropy of Thermal Ensembles for SYK-like models

Understand

The Sachdev-Ye-Kitaev model is an $N$-modes fermionic model with infinite range random interactions.

• In this work, we study the thermal R\'enyi entropy for a subsystem of the SYK model using the path-integral formalism in the large-$N$ limit.
• The results are consistent with exact diagonalization [1] and can be well approximated by thermal entropy with an effective temperature [2] when subsystem size $M\leq N/2$.
• We also consider generalizations of the SYK model with quadratic random hopping term or $U(1)$ charge conservation.