TY  - JOUR
AU  - Novotny, M. A.
AU  - Jin, F.
AU  - Yuan, S.
AU  - Miyashita, S.
AU  - De Raedt, H.
AU  - Michielsen, K.
TI  - Quantum decoherence and thermalization at finite temperature within the canonical-thermal-state ensemble
JO  - Physical review / A
VL  - 93
IS  - 3
SN  - 2469-9926
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2016-01906
SP  - 032110
PY  - 2016
AB  - We study measures of decoherence and thermalization of a quantum system S in the presence of a quantum environment (bath) E. The entirety S+E is prepared in a canonical-thermal state at a finite temperature; that is, the entirety is in a steady state. Both our numerical results and theoretical predictions show that measures of the decoherence and the thermalization of S are generally finite, even in the thermodynamic limit, when the entirety S+E is at finite temperature. Notably, applying perturbation theory with respect to the system-environment coupling strength, we find that under common Hamiltonian symmetries, up to first order in the coupling strength it is sufficient to consider S uncoupled from E, but entangled with E, to predict decoherence and thermalization measures of S. This decoupling allows closed-form expressions for perturbative expansions for the measures of decoherence and thermalization in terms of the free energies of S and of E. Large-scale numerical results for both coupled and uncoupled entireties with up to 40 quantum spins support these findings.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000371724100003
DO  - DOI:10.1103/PhysRevA.93.032110
UR  - https://juser.fz-juelich.de/record/283596
ER  -