6 papers
Non-Hermitian Rayleigh-Schrödinger-like Perturbation Theory at Exceptional Point
Wei-Ming Chen, Chia-Yi Ju
We develop a Rayleigh--Schrödinger-like perturbation theory for non-Hermitian quantum systems at an exceptional point of order . Working in the Jordan basis of the unperturbed…
Fidelity and quantum geometry approach to Dirac exceptional points in diamond nitrogen-vacancy centers
Chia-Yi Ju, Gunnar Möller, Yu-Chin Tzeng
Dirac exceptional points (EPs) represent a novel class of non-Hermitian singularities that, unlike conventional EPs, reside entirely within the parity-time unbroken phase and exhib…
Quantum State Evolution and Berry Potentials at Exceptional Points and Quantum Phase Transitions
Chia-Yi Ju, Fu-Hsiang Huang
The behavior of quantum states at exceptional points and at critical points associated with quantum phase transitions is intriguing yet puzzling. In this study, we present an alter…
Evidence for Exceptional Points as Topological Defects
Chia-Yi Ju, Szu-Ming Chen
Studies have shown that quantum states reside in a Hilbert space bundle. When a quantum system depends on continuous external parameters, these parameters define additional dimensi…
Heisenberg and Heisenberg-Like Representations via Hilbert Space Bundle Geometry in the Non-Hermitian Regime
Chia-Yi Ju, Adam Miranowicz, Jacob Barnett +2
The equivalence between the Schrödinger and Heisenberg representations is a cornerstone of quantum mechanics. However, this relationship remains unclear in the non-Hermitian regime…
Non-Hermitian Generalization of Rayleigh-Schrödinger Perturbation Theory
Wei-Ming Chen, Yen-Ting Lin, Chia-Yi Ju
While perturbation theories constitute a significant foundation of modern quantum system analysis, extending them from the Hermitian to the non-Hermitian regime remains a non-trivi…