On the limitations of a measurement-assisted optomechanical route to quantum macroscopicity of superposition states

Understand

Optomechanics is currently believed to provide a promising route towards the achievement of genuine quantum effects at the large, massive-system scale.

• By using a recently proposed figure of merit that is well suited to address continuous-variable systems, in this paper we analyze the requirements needed for the state of a mechanical mode (embodied by an end-cavity cantilever or a membrane placed within an optical cavity) to be qualified as macroscopic.
• We show that, according to the phase space-based criterion that we have chosen for our quantitative analysis, the state achieved through strong single-photon radiation-pressure coupling to a quantized field of light and conditioned by measurements operated on the latter might be interpreted as macroscopically quantum.
• In general, though, genuine macroscopic quantum superpositions appear to be possible only under quite demanding experimental conditions.