2024/06/24 by Shujie Cheng, Cheng, Shujie, Shuai-Peng Wang +5
Physics and Astronomy · #Advanced Fiber Laser Technologies #FOS: Physical sciences #Nonlinear Photonic Systems #Quantum Gases (cond-mat.quant-gas) #Quantum Mechanics and Non-Hermitian Physics #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2406.16576
openalex publication_date 2024/06/24 · openalex created_date 2024/06/26 · openalex updated_date 2026/07/28
This study investigates phase-driven symmetry breaking leading to superradiance phase transitions in cascaded non-Hermitian quantum Rabi cavities. Non-Hermiticity is introduced via the phase coupling φ between the atom and the optical field. In the thermodynamic limit of the quantum harmonic oscillator, we analytically derive the superradiance phase boundary, validated by observables. An unconventional quantum phase transition without a Hermitian analogue arises when |φ|=\fracπ4 or |φ|=(3π)/(4), where the phase boundary is uniquely determined by the cavity coupling, at J=(1)/(2), independent of the atom-photon coupling strength g. For other φ, the phase boundary relies on both J and g, similar to the scenario observed in Hermitian systems. Furthermore, we identify phase-driven first- and second-order superradiance phase transitions, focusing on the quantum criticality of the second-order transition by determining the critical exponents and the universality class. The feasibility of experimental realization is also discussed, aiming to inspire further studies on non-Hermitian superradiance quantum phase transitions.