Quantum Quench Dynamics of Geometrically Frustrated Ising Models

TL;DR

This paper explores the quantum quench dynamics of geometrically frustrated Ising models using a superconducting quantum annealer, revealing that their dynamics deviate from traditional Kibble-Zurek scaling and showcasing the annealer's capability to simulate complex quantum phenomena.

Contribution

It demonstrates the use of a quantum annealer to simulate large-scale quantum dynamics of frustrated Ising models, surpassing classical computational limitations.

Findings

Dominant quench dynamics are not described by quantum Kibble-Zurek scaling.

Observed coarsening dynamics differ from Kibble-Zurek expectations.

Quantum annealers can effectively simulate coherent quantum dynamics at large scales.

Abstract

Geometric frustration in two-dimensional Ising models allows for a wealth of exotic universal behavior, both Ising and non-Ising, in the presence of quantum fluctuations. In particular, the triangular antiferromagnet and Villain model in a transverse field can be understood through distinct XY pseudospins, but have qualitatively similar phase diagrams including a quantum phase transition in the (2+1)-dimensional XY universality class. While the quantum dynamics of modestly-sized systems can be simulated classically using tensor-based methods, these methods become infeasible for larger lattices. Here we perform both classical and quantum simulations of these dynamics, where our quantum simulator is a superconducting quantum annealer. Our observations on the triangular lattice suggest that the dominant quench dynamics are not described by the quantum Kibble-Zurek scaling of the quantum phase transition, but rather a faster coarsening dynamics in an effective two-dimensional XY model in the ordered phase. Similarly, on the Villain model, the scaling exponent does not match the Kibble-Zurek expectation. These results demonstrate the ability of quantum annealers to simulate coherent quantum dynamics and scale beyond the reach of classical approaches.