Time-averaged quantum annealing for weak processes
Abstract
The quantum Ising chain has shortcuts to adiabaticity when operated with weak processes. However, when exactly do the non-equilibrium effects of the Kibble-Zurek mechanism, inherent to the system, appear in the optimal protocols in such a context? I propose here that such contrasting difference occurs due to the manner by which one measures the excitation spent energy of the system. Therefore, in this work, I made a qualitative analysis of a quantum annealing procedure of the time-averaged excess work, where the system acquires as a diverging decorrelation time the heuristic Kibble-Zurek mechanism relaxation time. Four important effects are then observed: the absence of shortcuts to adiabaticity, the pausing effect around the critical point in the optimal protocol when the Kibble-Zurek mechanism holds, the persistence of the time-averaged work to avoid slowly-varying regime even for large switching times, and diverging fluctuations of the time-averaged work. In the end, by comparing the excess and the time-averaged excess works, I conclude that this last one is not useful to measure the excitation spent energy in weak processes, although brings an intuition to what happens in the strong driving case.
Cite
@article{arxiv.2306.06008,
title = {Time-averaged quantum annealing for weak processes},
author = {Pierre Nazé},
journal= {arXiv preprint arXiv:2306.06008},
year = {2023}
}
Comments
6 pages, 2 figures. arXiv admin note: text overlap with arXiv:2303.15609, arXiv:2305.17802, arXiv:2210.16116