Inseparability in parity-time-symmetric microcavities: power spectrum

We have theoretically described the possibility of entangled state and steerable state in parity-time-symmetric (PT\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathcal{P}\mathcal{T}}$$\end{document}-symmetric) microcavities. Temporal variation of entangled state is studied for different photon tunnelling strength and Kerr nonlinear interaction strength and also with different gain-to-loss ratio. Different entanglement criteria show that entangled state is not possible for passive-passive cavity system. But for passive-active cavity system i.e. PT\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathcal{P}\mathcal{T}}$$\end{document}-symmetry system, there is possibility of entangled state and degree of entanglement is enhanced significantly and also increases with gain-to-loss ratio. The present system also exhibits asymmetric steering. These properties of the system may be used for quantum information purposes. Using fast Fourier transform, we have studied frequency spectra of the system. Number of sideband can be tuned via photon tunnelling strength between the cavities. This study shows that present system may be used as a source of sideband generation with megahertz line spacing.