3 papers
quant-ph2025
Macroscopic quantum states, quantum phase transition for three-level atoms in an optical cavity -- Gauge principle and non-Hermitian Hamiltonian
Ni Liu, Xinyu Jia, J. -Q. Liang
We study in this paper the quantum phase transition (QPT) from normal phase (NP) to superradiant phase (SP) for three-level atoms in a single-mode optical cavity for both Hermi…
quant-ph2025
Quantum mechanics of inverted potential well -- Hermitian Hamiltonian with imaginary eigenvalues, quantum-classical correspondence
Ni Liu, J. -Q. Liang
We in this paper study the quantization of a particle in an inverted potential well. The Hamiltonian is Hermitian, while the potential is unbounded below. Classically the particle…
quant-ph2025
Imaginary eigenvalues of Hermitian Hamiltonian with an inverted potential well and transition to the real spectrum at exceptional point by a non-Hermitian interaction
Ni Liu, Meng Luo, J. -Q. Liang
We in this paper study the hermiticity of Hamiltonian and energy spectrum for the SU(1; 1) systems. The Hermitian Hamiltonian can possess imaginary eigenvalues in contrast with the…