摘要The dynamics of the spin-boson model with an Ohmic bath at finite temperature is studied by a variational calculation. Numerical solution of the self-consistent equation derived from the variational method shows that the transition from incoherent to coherent phases is discontinuous. It indicates that (T=0,s=1) is a tricritical point, i.e. the transition changes from continuous to discontinuous by tuning from T=0 to T≠0. The discontinuous transition at finite temperature is analysed by Landau theory and the relation to the experimental observation on the coherent state is also discussed.
Abstract：The dynamics of the spin-boson model with an Ohmic bath at finite temperature is studied by a variational calculation. Numerical solution of the self-consistent equation derived from the variational method shows that the transition from incoherent to coherent phases is discontinuous. It indicates that (T=0,s=1) is a tricritical point, i.e. the transition changes from continuous to discontinuous by tuning from T=0 to T≠0. The discontinuous transition at finite temperature is analysed by Landau theory and the relation to the experimental observation on the coherent state is also discussed.
CHEN Wen;CHEN Zhi-De. Quantum Tricritical Point in the Spin-Boson Model with an Ohmic Bath[J]. 中国物理快报, 2007, 24(5): 1140-1143.
CHEN Wen, CHEN Zhi-De. Quantum Tricritical Point in the Spin-Boson Model with an Ohmic Bath. Chin. Phys. Lett., 2007, 24(5): 1140-1143.
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