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

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.
Authors:
 [1] ;  [2] ; ;  [1] ;  [3]
  1. Division of Materials Science, Nanyang Technological University, Singapore 639798 (Singapore)
  2. (China)
  3. Department of Physics, Hangzhou Normal University, Hangzhou 310046 (China)
Publication Date:
OSTI Identifier:
22493627
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 144; Journal Issue: 2; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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