Title: Dark-state solution and hidden symmetries of the two-qubit multimode asymmetric quantum Rabi model Show Chinese title

Title: 暗态解和两量子比特多模非对称量子Rabi模型的隐藏对称性

Abstract: We study the two-qubit asymmetric quantum Rabi model (AQRM) and find another hidden symmetry related to its dark-state solution. Such a solution has at most one photon and constant eigenenergy in the whole coupling regime, causing level crossings in the spectrum, although there is no explicit conserved quantity except energy, indicating another hidden symmetry. We find a symmetric operator in the eigenenergy basis to label the degeneracy with its eigenvalues, and compare it with the well-known hidden symmetry which exists when bias parameter $\epsilon$ is a multiple of half of the resonator frequency. Extended to the multimode case, we find not only hidden symmetries mentioned above, but also symmetries related with conserved bosonic number operators. This provides a new perspective for hidden symmetry studies on generalized Rabi models. Show Chinese abstract

Abstract: 我们研究了两量子比特非对称量子Rabi模型（AQRM），并发现与其暗态解相关的另一种隐藏对称性。 这种解在整个耦合区域内最多包含一个光子且本征能量恒定，导致谱中的能级交叉，尽管除了能量之外没有显式的守恒量，这表明存在另一种隐藏对称性。 我们在本征能量基底下找到一个对称算符，用其本征值来标记简并，并将其与当偏置参数$\epsilon$为谐振器频率一半的倍数时存在的已知隐藏对称性进行比较。 扩展到多模情况，我们不仅发现了上述隐藏对称性，还发现了与守恒的玻色子数算符相关的对称性。 这为广义Rabi模型的隐藏对称性研究提供了新的视角。