Quantum phase transitions of the spin-boson model within multi-coherent-states

Liwei Duan; Shu He; Qing-Hu Chen

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arXiv · 1412.6343

Quantum phase transitions of the spin-boson model within multi-coherent-states

Liwei Duan·Shu He·Qing-Hu Chen

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Abstract

A variational approach based on the multi-coherent-state ansatz with asymmetric parameters is employed to study the ground state of the spin-boson model. Without any artificial approximations except for the finite number of the coherent states, we find the robust Gaussian critical behavior in the whole sub-Ohmic bath regime. The converged critical coupling strength can be estimated with the $1/N$ scaling, where $N $ is the number of the coherent states. It is strongly demonstrated the breakdown of the well-known quantum-to-classical mapping for $1/2<s<1$. In addition, the entanglement entropy displays more steep jump around the critical points for the Ohmic bath than the sub-Ohmic bath.

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BibTeX RIS

Liwei Duan, Shu He, Qing-Hu Chen. 2014-12-19. Quantum phase transitions of the spin-boson model within multi-coherent-states. https://arxiv.org/abs/1412.6343

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