Quantum annealing with ultracold atoms in a multimode optical resonator

TL;DR

This paper proposes a method to implement quantum annealing using ultracold atoms in a multimode optical resonator, enabling controllable all-to-all spin interactions and robust ground state preparation.

Contribution

It introduces a scheme for quantum annealing with tunable long-range interactions in a cold atom system within a multimode cavity, including error correction and state readout techniques.

Findings

Real-time control of spin interactions via laser beams.

Ground state can be reached despite cavity losses and finite temperature.

Simulation of a quantum Hopfield associative memory scheme.

Abstract

A dilutely filled $N$-site optical lattice near zero temperature within a high-$Q$ multimode cavity can be mapped to a spin ensemble with tailorable interactions at all length scales. The effective full site to site interaction matrix can be dynamically controlled by the application of up to $N(N+1)/2$ laser beams of suitable geometry, frequency and power, which allows for the implementation of quantum annealing dynamics relying on the all-to-all effective spin coupling controllable in real time. Via an adiabatic sweep starting from a superfluid initial state one can find the lowest energy stationary state of this system. As the cavity modes are lossy, errors can be amended and the ground state can still be reached even from a finite temperature state via ground state cavity cooling. The physical properties of the final atomic state can be directly and almost non-destructively read off from the cavity output fields. As example we simulate a quantum Hopfield associative memory scheme.