N=2 SYK models with dynamical bosons and fermions

We study a class of SYK models with N=2 supersymmetry, described by N fermions in chiral Fermi multiplets, as well as α N first-order bosons in chiral multiplets. The interactions are characterised by two integers $(p,q)$. We focus on the large N and low energy limit of these models. Despite the presence of dynamical bosons, we find conformal behaviour akin to the standard SYK model. We use I-extremization of a Witten index to study the supersymmetric solutions. In particular, we find an exact expression for the entropy, which matches the numerical solutions to the Schwinger-Dyson equations. We further solve the model both in the large p and large $p,q$ limits. Numerically, we verify our analytical results and obtain estimates for the Schwarzian coupling in the near zero-temperature limit. We also study the low-lying spectrum of operators to determine the parameter ranges where the Schwarzian mode dominates the IR dynamics. Lastly, we study out-of-time-ordered correlators to show that the model is maximally chaotic.