Oral : Self induced oscillations in a non-linearly coupled magnetomechanical system

Backaction effects in optomechanical systems can be exploited to efficiently cool thermally excited mechanical states towards their ground state. However, within specific operational regimes, the resulting backaction can give rise to a negative damping rate, consequently leading to heating of the mechanical mode and subsequently to a break-down of the linear theory. The interplay of nonlinear effects and dissipation can lead to self induced oscillations with a fixed amplitude.

Our current study focuses on the theoretical modeling of a nonlinear magnetomechanical system that exhibits self-induced oscillations. In such inductively-coupled electromechanical systems, the interaction between the mechanical mode and the microwave cavity mode is effectively mediated via a SQUID loop, thus the nonlinear aspect of the system is strongly enhanced as the cavity mode is itself nonlinear. This non-linearity gives us access to bistable regime at much low powers, making it an important aspect to consider while obtaining the correct photon numbers. We compare our theoretical predictions with experimental data.