TY - JOUR
T1 - Equilibration of multitime quantum processes in finite time intervals
AU - Dowling, Neil
AU - Figueroa-Romero, Pedro
AU - Pollock, Felix A.
AU - Strasberg, Philipp
AU - Modi, Kavan
N1 - Funding Information:
ND is supported by an Australian Government Research Training Program Scholarship and the Monash Graduate Excellence Scholarship. PS acknowledges financial support from a fellowship from “la Caixa” Foundation (ID 100010434, fellowship code LCF/BQ/PR21/11840014) and from the Spanish Agencia Estatal de Investigación (project no. PID2019-107609GB-I00), the Spanish MINECO (FIS2016-80681-P, AEI/FEDER, UE), and the Generalitat de Catalunya (CIRIT 2017-SGR-1127). KM is supported through Australian Research Council Future Fellowship FT160100073, Discovery Project DP210100597, and the International Quantum U Tech Accelerator award by the US Air Force Research Laboratory.
Publisher Copyright:
© 2023 Revista Facultad Nacional de Salud Publica. All rights reserved.
PY - 2023/6/14
Y1 - 2023/6/14
N2 - A generic non-integrable (unitary) out-of-equilibrium quantum process, when interrogated across many times, is shown to yield the same statistics as an (non-unitary) equilibrated process. In particular, using the tools of quantum stochastic processes, we prove that under loose assumptions, quantum processes equilibrate within finite time intervals. Sufficient conditions for this to occur are that multitime observables are coarse grained in both space and time, and that the initial state overlaps with many different energy eigenstates. These results help bridge the gap between (unitary) quantum and (non-unitary) statistical physics, i.e., when all multitime properties and correlations are well approximated by stationary quantities, which includes non-Markovianity and temporal entanglement. We discuss implications of this result for the emergence of classical stochastic processes from multitime measurements of an underlying genuinely quantum system.
AB - A generic non-integrable (unitary) out-of-equilibrium quantum process, when interrogated across many times, is shown to yield the same statistics as an (non-unitary) equilibrated process. In particular, using the tools of quantum stochastic processes, we prove that under loose assumptions, quantum processes equilibrate within finite time intervals. Sufficient conditions for this to occur are that multitime observables are coarse grained in both space and time, and that the initial state overlaps with many different energy eigenstates. These results help bridge the gap between (unitary) quantum and (non-unitary) statistical physics, i.e., when all multitime properties and correlations are well approximated by stationary quantities, which includes non-Markovianity and temporal entanglement. We discuss implications of this result for the emergence of classical stochastic processes from multitime measurements of an underlying genuinely quantum system.
UR - http://www.scopus.com/inward/record.url?scp=85164562817&partnerID=8YFLogxK
U2 - 10.21468/SciPostPhysCore.6.2.043
DO - 10.21468/SciPostPhysCore.6.2.043
M3 - Article
AN - SCOPUS:85164562817
SN - 2666-9366
VL - 6
JO - SciPost Physics Core
JF - SciPost Physics Core
IS - 2
M1 - 043
ER -