Non-Markovian Quantum Exceptional Points

Jhen-Dong Lin^1,2*, Po-Chen Kuo³, Neill Lambert⁴, Adam Miranowicz^4,5, Franco Nori^4,6, Yueh-Nan Chen^1,2,7

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Center for Quantum Frontiers of Research & Technology, National Cheng Kung University, Tainan, Taiwan
³Department of Applied Physics, National Pingtung University, Pingtung, Taiwan
⁴Center for Quantum Computing, RIKEN, Wakoshi, Saitama, Japan
⁵Institute of Spintronics and Quantum Information, Faculty of Physics, Adam Mickiewicz University, Pozna´n, Poland
⁶Quantum Research Institute, The University of Michigan, Ann Arbor, Michigan, USA
⁷Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan

* Presenter:Jhen-Dong Lin, email:jhendonglin@gmail.com

Exceptional points (EPs) are singularities in the spectra of non-Hermitian operators where eigenvalues and eigenvectors coalesce. Open quantum systems have recently been explored as EP testbeds due to their non-Hermitian nature. This work addresses this gap by proposing a general framework based on two numerically exact descriptions of non-Markovian dynamics: the pseudomode equation of motion (PMEOM) and the hierarchical equations of motion (HEOM). This framework incorporates non-Markovian effects through auxiliary degrees of freedom, enabling the discovery of additional or higher-order EPs that are inaccessible in the Markovian regime. We demonstrate the utility of this approach using the spin-boson model and linear bosonic systems.

Keywords: Quantum Exceptional Point, Open Quantum System, Non-Markovian effects