3 papers
quant-ph2026
Exact Solution for Non-Hermitian Free Fermions: A Case Study of the XY Chain
Yuguan Li, D. C. Liu, Murray T. Batchelor
We consider the non-Hermitian XY spin chain with open boundary conditions when the anisotropy parameter is extended to complex values. By analyzing the quasi-Hamiltonian matrix, we…
quant-ph2025
Exceptional point rings and -symmetry in the non-Hermitian XY model
Robert A. Henry, D. C. Liu, Murray T. Batchelor
The XY spin chain is a paradigmatic example of a model solved by free fermions, in which the energy eigenspectrum is built from combinations of quasi-energies. In this article we s…
quant-ph2025
Characterizing phase transitions and criticality in non-Hermitian extensions of the XY model
D. C. Liu, Murray T. Batchelor
In this work we study non-Hermitian extensions of the paradigmatic spin-1/2 XY chain in a magnetic field. Using the mapping of the model to free fermion form, we provide analytical…