Quantum instability and edge entanglement in the quasi-long-range order

摘要: We investigate the buildup of quasi-long-range order in $XX$ chain with a transverse magnetic field at finite size. As is varied, ground state system displays multiple level crossings producing sequence entanglement jumps. Using partial fidelity and susceptibility, we study transition to thermodynamic limit argue that topological can be described terms kink-antikink pairs marked by edge spin entanglement.