Shortcuts to adiabatic cat-state generation in bosonic Josephson junctions

TL;DR

This paper introduces a shortcut to adiabaticity method for faster generation of highly entangled cat states in bosonic Josephson junctions, overcoming divergence issues with finite-size corrections.

Contribution

It develops an approximated counter-diabatic driving scheme with finite-size corrections for efficient cat state generation in bosonic Josephson junctions.

Findings

Successfully accelerates adiabatic generation of cat states

Generated states exhibit high quantum Fisher information

Method avoids divergence issues in counter-diabatic driving

Abstract

We propose a quantum speedup method for adiabatic generation of cat states in bosonic Josephson junctions via shortcuts to adiabaticity. We apply approximated counter-diabatic driving to a bosonic Josephson junction using the Holstein-Primakoff transformation. In order to avoid the problem of divergence in counter-diabatic driving, we take finite-size corrections into account. The resulting counter-diabatic driving is well-defined over whole processes. Schedules of the counter-diabatic driving consist of three steps; the counter-diabatic driving in the disordered phase, smoothly and slowly approaching the critical point, and the counter-diabatic driving in the ordered phase. Using the counter-diabatic driving, adiabatic generation of cat states is successfully accelerated. The enough large quantum Fisher information ensures that generated cat states are highly entangled.