Exponential acceleration of macroscopic quantum tunneling in a Floquet Ising model

TL;DR

This paper demonstrates that applying a high-frequency transverse drive to a Floquet Ising model exponentially accelerates macroscopic quantum tunneling, overcoming a key bottleneck in quantum algorithms and phase transitions.

Contribution

It introduces Floquet engineering as a method to exponentially enhance quantum tunneling rates in the Ising model, supported by numerical simulations and theoretical analysis.

Findings

Exponential acceleration of tunneling with strong drives

Identification of three regimes based on drive strength

Potential for experimental validation on NISQ quantum computers

Abstract

The exponential suppression of macroscopic quantum tunneling (MQT) in the number of elements to be reconfigured is an essential element of broken symmetry phases. This suppression is also a core bottleneck in quantum algorithms, such as traversing an energy landscape in optimization, and adiabatic state preparation more generally. In this work, we demonstrate exponential acceleration of MQT through Floquet engineering with the application of a uniform, high frequency transverse drive field. Using the ferromagnetic phase of the transverse field Ising model in one and two dimensions as a prototypical example, we identify three phenomenological regimes as a function of drive strength. For weak drives, the system exhibits exponentially decaying tunneling rates but robust magnetic order; in the crossover regime at intermediate drive strength, we find polynomial decay of tunnelling alongside vanishing magnetic order; and at very strong drive strengths both the Rabi frequency and time-averaged magnetic order are approximately constant with increasing system size. We support these claims with extensive full wavefunction and tensor network numerical simulations, and theoretical analysis. An experimental test of these results presents a technologically important and novel scientific question accessible on NISQ-era quantum computers.