Non-local reparametrization action in coupled Sachdev-Ye-Kitaev models

TL;DR

This paper explores coupled SYK models where a non-local reparametrization action dominates, revealing significant differences from Schwarzian-based models in thermodynamics and correlation functions, while retaining key chaotic properties.

Contribution

It introduces a non-local reparametrization action in coupled SYK models and analyzes its effects on thermodynamics and chaos, extending understanding beyond Schwarzian-dominated regimes.

Findings

Thermodynamic properties differ from Schwarzian predictions.

4-point functions show significant deviations.

Residual entropy and chaos exponent remain unchanged.

Abstract

We continue the investigation of coupled Sachdev-Ye-Kitaev(SYK) models without Schwarzian action dominance. Like the original SYK, at large N and low energies these models have an approximate reparametrization symmetry. However, the dominant action for reparametrizations is non-local due to the presence of irrelevant local operator with small conformal dimension. We semi-analytically study different thermodynamic properties and the 4-point function and demonstrate that they significantly differ from the Schwarzian prediction. However, the residual entropy and maximal chaos exponent are the same as in Majorana SYK. We also discuss chain models and finite N corrections.