The International Conference on Quantum Foundation and Technology: Frontier and Future
(ICQFT’09))。
Entanglement, Fidelity Susceptibility, and Quantum Phase Transition
H. Q. Lin
Department of Physics and Institute of Theoretical Physics
The Chinese University of Hong Kong, Hong Kong, China
Whether it is possible and how to witness quantum phase transition (QPT) in many-body
systems from quantum information point of view such as the entanglement and its measure
is the central issue addressed in this talk. I report our group recent efforts in exploring the
relation between QPT and two quantum information concepts: entanglement and fidelity.
First we introduce quantities we used to measure the entanglement and fidelity
susceptibility. Then we study their behaviors in several well known quantum many-body
systems such as the extended Hubbard model and Kitaev honeycomb model. We argue the
important role played by the low-lying excitation spectra reconstruction near the QPT in
identifying the behavior of the entanglement and QPT, and show that that the fidelity
susceptibility can be used to identify topological phase transition from a disorder phase
with Abelian anyon excitations to another disorder phase with non-Abelian anyon
excitations. It is hoped that a unified and intuitive picture on the relation between the QPT
and quantum information.
*Work supported by Hong Kong SAR RGC Grants, Project N_CUHK204/05.