Articolo in rivista, 2019, ENG, 10.1103/PhysRevB.99.064201

Dynamics of simulated quantum annealing in random Ising chains

Mbeng G.B.; Privitera L.; Arceci L.; Santoro G.E.

SISSA, Via Bonomea 265, Trieste, I-34136, , Italy; INFN, Sezione di Trieste, Trieste, I-34136, , Italy; Institute of Theoretical Physics and Astrophysics, University of Würzburg, Würzburg, 97074, , Germany; ICTP, Strada Costiera 11, Trieste, 34151, , Italy; CNR-IOM Democritos National Simulation Center, Via Bonomea 265, Trieste, I-34136, , , Italy; CNR-IOM Democritos National Simulation Center, Via Bonomea 265, Trieste, I-34136, , , Italy

Simulated quantum annealing (SQA) is a classical computational strategy that emulates a quantum annealing (QA) dynamics through a path-integral Monte Carlo whose parameters are changed during the simulation. Here we apply SQA to the one-dimensional transverse field Ising chain, where previous works have shown that, in the presence of disorder, a coherent QA provides a quadratic speedup with respect to classical simulated annealing, with a density of Kibble-Zurek defects decaying as ?KZQA~(log10?)-2 as opposed to ?KZSA~(log10?)-1, ? being the total annealing time, while for the ordered case both give the same power law ?KZQA??KZSA~?-1/2. We show that the dynamics of SQA, while correctly capturing the Kibble-Zurek scaling ?-1/2 for the ordered case, is unable to reproduce the QA dynamics in the disordered case at intermediate ?. We analyze and discuss several issues related to the choice of the Monte Carlo moves (local or global in space), the time-continuum limit needed to eliminate the Trotter-discretization error, and the long autocorrelation times shown by a local-in-space Monte Carlo dynamics for large disordered samples.

Physical Review B 99 (6)

Keywords

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CNR authors

Santoro Giuseppe Ernesto

CNR institutes

IOM – Istituto officina dei materiali

ID: 424506

Year: 2019

Type: Articolo in rivista

Creation: 2020-06-25 12:02:56.000

Last update: 2020-06-25 12:02:56.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:424506

DOI: 10.1103/PhysRevB.99.064201

Scopus: 2-s2.0-85061350223