Dynamics of the spin-boson model: The effect of bath initial conditions

Lipeng Chen; Yiying Yan; Maxim F Gelin; Zhiguo Lü

doi:10.1063/5.0138399

Dynamics of the spin-boson model: The effect of bath initial conditions

J Chem Phys. 2023 Mar 14;158(10):104109. doi: 10.1063/5.0138399.

Authors

Lipeng Chen¹, Yiying Yan², Maxim F Gelin³, Zhiguo Lü⁴

Affiliations

¹ Zhejiang Laboratory, Hangzhou 311100, China.
² Department of Physics, School of Science, Zhejiang University of Science and Technology, Hangzhou 310023, China.
³ School of Science, Hangzhou Dianzi University, Hangzhou 310018, China.
⁴ Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.

PMID: 36922121
DOI: 10.1063/5.0138399

Abstract

The dynamics of the (sub-)Ohmic spin-boson model under various bath initial conditions is investigated by employing the Dirac-Frenkel time-dependent variational approach with the multiple Davydov D₁ Ansatz in the interaction picture. The validity of our approach is carefully checked by comparing the results with those of the hierarchy equations of motion method. By analyzing the features of nonequilibrium dynamics, we identify the phase diagrams for different bath initial conditions. We find that for the spectral exponent s < s_c, there exists a transition from coherent to quasicoherent dynamics with increasing coupling strengths. For s_c < s ≤ 1, the coherent to incoherent crossover occurs at a certain coupling strength and the quasicoherent dynamics emerges at much larger couplings. The initial preparation of the bath has a considerable influence on the dynamics.