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arXiv · 0805.3885

Partial-state fidelity and quantum phase transitions induced by continuous level crossing

Ho-Man Kwok·Chun-Sing Ho·Shi-Jian Gu
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Abstract

The global-state fidelity cannot characterize those quantum phase transitions (QPTs) induced by continuous level crossing due to its collapse around each crossing point. In this paper, we take the isotropic Lipkin-Meshkov-Glick (LMG) model and the antiferromagnetic one-dimensional Heisenberg model as examples to show that the partial-state fidelity can signal such level-crossing QPTs. Extending to the thermodynamic limit we introduce the partial-state fidelity susceptibility and study its scaling behavior. The maximum of the partial-state fidelity susceptibility goes like $N$ for the LMG model and $N^3$ for the Heisenberg model.

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Ho-Man Kwok, Chun-Sing Ho, Shi-Jian Gu. 2008-05-28. Partial-state fidelity and quantum phase transitions induced by continuous level crossing. https://doi.org/10.1103/physreva.78.062302

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