3 papers
physics.optics2025
Exceptional Points and Lasing Thresholds: When Lower-Q Modes Win
Julius Kullig, Qi Zhong, Jan Wiersig +1
One of the most fundamental questions in laser physics is the following: Which mode of an optical cavity will reach the lasing threshold first when gain is applied? Intuitively, th…
physics.optics2025
Generalized Petermann factor of non-Hermitian systems at exceptional points
Julius Kullig, Jan Wiersig, Henning Schomerus
The nonorthogonality of modes in open systems significantly modifies their resonant response, resulting in quantitative and qualitative deviations from Breit-Wigner resonance relat…
quant-ph2025
Higher-order exceptional points in composite non-Hermitian systems
Jan Wiersig, Weijian Chen
We show that a composite quantum system described by the tensor product of multiple systems each with a leading-order exceptional point (a non-Hermitian degeneracy at which not onl…