FisMat2017 - Submission - View

Abstract's title: Dissipative Landau-Zener problem and thermally assisted quantum annealing
Submitting author: Luca Arceci
Affiliation: SISSA - Scuola Internazionale Superiore di Studi Avanzati
Affiliation Address: Scuola Internazionale Superiore di Studi Avanzati - via Bonomea, 265 - 34136 Trieste ITALY
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: S. Barbarino (SISSA, Via Bonomea 265, Trieste), R. Fazio (International Centre for Theoretical Physics (ICTP), Trieste; NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa), G. E. Santoro (SISSA, Via Bonomea 265, Trieste; CNR-IOM Democritos National Simulation Center, Via Bonomea 265, Trieste; International Centre for Theoretical Physics (ICTP), Trieste)

I will present the issue of whether a dissipative environment can enhance the performance of a quantum annealer by a detailed study of the dissipative Landau-Zener problem in presence of a Caldeira-Leggett bath of harmonic oscillators. Some controversial results have appeared in the literature: I will shed light upon the issue, showing that a finite temperature bath can have a beneficial effect on the ground-state probability only if it couples also to a spin-direction that is transverse with respect to the driving field, while no improvement is obtained for the more commonly studied purely longitudinal coupling. Remarkably, for a transverse coupling, I will show that raising the bath temperature further improves the ground-state probability in the fast-driving regime.