The effect of thermal photons on exceptional points in coupled resonators
Abstract
We analyse two quantum systems with hidden parity-time (PT) symmetry: one is an optical device, whereas another is a superconducting microwave-frequency device. To investigate their symmetry, we introduce an equilibrium frame, in which loss and gain terms for a given Hamiltonian are balanced. We show that the non-Hermitian Hamiltonians of both systems can be tuned to reach an exceptional point (EP), i.e., the point in parameter space at which a transition from broken to unbroken hidden PT symmetry takes place. We calculate a degeneracy of a Liouvillian superoperator, which is called the Liouvillian exceptional point (LEP), and show that, in the optical domain, LEP is equivalent to EP obtained from the non-Hermitian Hamiltonian (HEP). We also report breaking the equivalence between LEP and HEP by a non-zero number of thermal photons for the microwave-frequency system.
Keywords
Cite
@article{arxiv.2305.08150,
title = {The effect of thermal photons on exceptional points in coupled resonators},
author = {Grzegorz Chimczak and Anna Kowalewska-Kudłaszyk and Ewelina Lange and Karol Bartkiewicz and Jan Peřina},
journal= {arXiv preprint arXiv:2305.08150},
year = {2023}
}
Comments
This preprint has not undergone peer review or any post-submission improvements or corrections. The Version of Record of this article is published in Scientific Reports, and is available online at https://doi.org/10.1038/s41598-023-32864-2