Chiral Sachdev-Ye model: Integrability and chaos of anyons in 1+1d

TL;DR

This paper introduces a chiral Sachdev-Ye model with anyon excitations in 1+1d, revealing integrable and chaotic regimes, and demonstrates maximal chaos in the large N, M limit with random interactions.

Contribution

It constructs a novel 1+1d chiral SY model with anyons, analyzing its integrability and chaos properties, including a solvable large N, M limit showing maximal chaos.

Findings

The model is integrable with uniform interactions, decomposing into chiral SU(M)_N WZW and coset models.

In the large N, M limit with randomness, the model exhibits many-body quantum chaos.

The Lyapunov exponent saturates the maximal chaos bound at high interaction strength.

Abstract

We construct and study a chiral Sachdev-Ye (SY) model consisting of $N$ chiral SU$(M)_1$ Wess-Zumino-Witten (WZW) models with current-current interactions among each other, which generalizes the 0+1d quantum chaotic SY spin model into 1+1d chiral system with anyon excitations. Each WZW model hosts Abelian anyons as charge excitations, and may arise as the chiral edge theory of 2+1d gapped topological phases. We solve the chiral SY model in two limits which show distinct quantum dynamics. The first limit is the case with uniform interactions at any integers $N$ and $M$, which is integrable and decomposes into a chiral SU$(M)_N$ WZW model and its coset with different "speed of light". When $N=M=2$, the model maps to a free Majorana fermion model. The second limit is the large $N$ and $M$ limit with random interactions, which is solvable to the leading $\frac{1}{NM}$ order, and exhibits many-body quantum chaos in the out-of-time-ordered correlation of anyons. As the interaction strength approaches the upper limit preserving the chirality, the leading velocity-dependent Lyapunov exponent of the model saturates the maximal chaos bound $2\pi/\beta$ at temperature $\beta^{-1}$.