Abstract
Based on the concepts of quantum synchronization and quantum phase synchronization proposed by A. Mari \textit{et al.} in Phys. Rev. Lett. 111, 103605 (2013), we introduce and characterize the measure of a more generalized quantum synchronization called quantum ϕ-synchronization under which the pairs of variables have the same amplitude and possess the same ϕ phase shift. Naturally, quantum synchronization and quantum anti-synchronization become special cases of quantum ϕ-synchronization. Their relations and differences are also discussed. To illustrate these theories, we investigate the quantum ϕ-synchronization and quantum phase synchronization phenomena of two coupled optomechanical systems with periodic modulation and show that quantum ϕ-synchronization is more general as a measure of synchronization. We also show the phenomenon of quantum anti-synchronization when ϕ=π.