Reduced fidelity susceptibility and its finite-size scaling behaviors in the Lipkin-Meshkov-Glick model.
We derive a general formula for the reduced fidelity susceptibility when the reduced density matrix is 2x2 block diagonal. By using this result and a continuous unitary transformation, we study finite-size scaling of the reduced fidelity susceptibility in the Lipkin-Meshkov-Glick model. It is found that it can well characterize quantum phase transitions, that is, we can extract information about quantum phase transitions from only the fidelity of a subsystem, which is of practical use in experiments.
Ma
Jian
J
Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, HangZhou 310027, People's Republic of China.
Xu
Lei
L
Xiong
Heng-Na
HN
Wang
Xiaoguang
X