Floquet modulation of \hbox{$\mathcal{PT}$}𝒫𝒯 symmetry in an atomic Bose-Josephson junction

Abstract

We study a periodically driven -symmetric Bose-Josephson junction and explore how the driving field affects the symmetry in such a non-Hermitian many-body quantum system. In the absence of interaction, by employing the high-frequency Floquet method, the condition of spontaneous -symmetry-breaking transition is analytically given. In the presence of interaction, it is found that even weak atom-atom interaction can shift the critical point of the -symmetry-breaking transition. Furthermore, we numerically obtain the -symmetric phase diagram, where the region of unbroken symmetry sensitively depends on the interaction strength and the driving parameter. Our results provide a promising way for manipulating -symmetric many-body quantum system by utilizing periodic driving fields.