Nonlinear effects in modulated quantum optomechanics

TLDR

The nonlinear quantum regime is essential for realizing quantum effects with broad applications in modern quantum science. We propose an effective method to access the nonlinear quantum regime in a weakly coupled modulated optomechanical system. By periodically modulating the mechanical spring constant and optomechanical interaction, the system achieves resonant enhancement of the optomechanical coupling. The modulation‑induced parametric amplification boosts the interaction into the single‑photon strong‑coupling regime, while a squeezed vacuum reservoir suppresses phonon noise to realize photon blockade and generate robust nonclassical cavity states, thereby offering a new route to enhance quantum nonlinearity in optomechanics.

Abstract

The nonlinear quantum regime is crucial for implementing interesting quantum effects, which have wide applications in modern quantum science. Here we propose an effective method to reach the nonlinear quantum regime in a modulated optomechanical system (OMS), which is originally in the weak-coupling regime. The mechanical spring constant and optomechanical interaction are modulated periodically. This leads to the result that the resonant optomechanical interaction can be effectively enhanced into the single-photon strong-coupling regime by the modulation-induced mechanical parametric amplification. Moreover, the amplified phonon noise can be suppressed completely by introducing a squeezed vacuum reservoir, which ultimately leads to the realization of photon blockade in a weakly coupled OMS. The reached nonlinear quantum regime also allows us to engineer the nonclassical states (e.g., Schr\"{o}dinger cat states) of cavity field, which are robust against the phonon noise. This work offers an alternative approach to enhance the quantum nonlinearity of an OMS, which should expand the applications of cavity optomechanics in the quantum realm.