title: Reduced fidelity susceptibility and its finite-size scaling behaviors in the Lipkin-Meshkov-Glick model.
abstract: 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.
authors.affiliation: Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, HangZhou 310027, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ma
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Heng-Na
authors.initials: HN
authors.lastname: Xiong
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Wang