Entropy generation in nonlinear levitated optomechanics

Classic thermodynamic predicts that during a physical transformation, the entropy of the system either stays constant or increases due to heat production. Indeed, by looking at the entropy production we can understand if the process is going forward (the entropy increases) or backward (the entropy decreases) in time. When considering smaller systems, however, new phenomena like random fluctuation, non-linear interactions and quantum behaviour must be accounted for. Non equilibrium quantum thermodynamics is a new research topic that focuses on the production of irreversible entropy in these general small-scale systems. Here we use optically levitated nanoparticles in vacuum as an experimental platform to measure the entropy production in a controllable out of equilibrium nonlinear systems. This platform allows for a versatile tuning of the nonlinearity of a levitated oscillator and to operate under far-from-equilibrium conditions. We will investigate entropy production of non-Gaussian states in the classical scenario and then we will push the system to a regime where the quantum nature of the oscillator becomes relevant. This project will represent a cornerstone in validating non-equilibrium quantum thermodynamics and will shed light on the emergence of irreversibility, leading to the origin of an arrow of time.