Quantum annealing and thermalization: insights from integrability

TL;DR

This paper provides an exact solution to a quantum annealing model with features like entanglement and controllable speed, revealing how quantum correlations can enhance computation and produce a perfect Gibbs distribution.

Contribution

It offers a nonperturbative, exact analysis of nonadiabatic excitations in a quantum annealing model with integrability, highlighting the role of quantum correlations in computation.

Findings

Nonperturbative characterization of excitations and their scaling.

Quantum correlations can accelerate quantum annealing.

Final state approaches a perfect Gibbs distribution.

Abstract

We solve a model that has basic features that are desired for quantum annealing computations: entanglement in the ground state, controllable annealing speed, ground state energy separated by a gap during the whole evolution, and a programmable computational problem that is encoded by parameters of the Ising part of the spin Hamiltonian. Our solution enables exact nonperturbative characterization of final nonadiabatic excitations, including a scaling of their number with the annealing rate and the system size. We prove that quantum correlations can accelerate computations and, at the end of the annealing protocol, lead to the perfect Gibbs distribution of all microstates.