Variational dynamics of the sub-Ohmic spin-boson model on the basis of multiple Davydov D{sub 1} states

Journal Article · Thu Jan 14 04:00:00 EST 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4939144· OSTI ID:22493627

Wang, Lu ^[1]; Chen, Lipeng; Zhao, Yang ^[1]; Zhou, Nengji ^[2]

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1. Division of Materials Science, Nanyang Technological University, Singapore 639798 (Singapore)
2. Department of Physics, Hangzhou Normal University, Hangzhou 310046 (China)

Dynamics of the sub-Ohmic spin-boson model is investigated by employing a multitude of the Davydov D{sub 1} trial states, also known as the multi-D{sub 1} Ansatz. Accuracy in dynamics simulations is improved significantly over the single D{sub 1} Ansatz, especially in the weak system-bath coupling regime. The reliability of the multi-D{sub 1} Ansatz for various coupling strengths and initial conditions is also systematically examined, with results compared closely with those of the hierarchy equations of motion and the path integral Monte Carlo approaches. In addition, a coherent-incoherent phase crossover in the nonequilibrium dynamics is studied through the multi-D{sub 1} Ansatz. The phase diagram is obtained with a critical point s{sub c} = 0.4. For s{sub c} < s < 1, the coherent-to-incoherent crossover occurs at a certain coupling strength, while the coherent state recurs at a much larger coupling strength. For s < s{sub c}, only the coherent phase exists.

• OSTI ID: 22493627
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 2 Vol. 144; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNIHILATION OPERATORS
BOSONS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
COUPLING
D STATES
EIGENSTATES
EQUATIONS OF MOTION
MONTE CARLO METHOD
PATH INTEGRALS
PHASE DIAGRAMS
RELIABILITY
SPIN
VARIATIONAL METHODS