Quantum Entanglement from Superradiance and the Hawking effect in Fluids of Light

Objective

Our understainding of superradiance regards it as a phenomenon of classical amplification. Leveraging techniques from Quantum Field Theory in Curved Spacetimes and Gaussian quantum information, I will provide a theoretical proof that superradiance generates entanglement and is inherently quantum, calling for a revision of the current paradigm. It is believed that a horizonless system displaying rotational superradiance is unstable. Given that horizons generate Hawking radiation, this prevents the study of superradiance in isolation from the latter, which also generates entanglement and hinders a clean observation of our novel prediciton. I propose to overcome this difficulty through dissipative dynamics. Polariton fluids are dissipative quantum fluids that allow for homodyne detection, thus being ideal platforms to test our predictions. I will quantify the entanglement generated by an isolated ergoregion in a rotating polariton fluid, and characterize it as a function of relevant experimental parameters. I will follow by extending our methods to quantify, for the first time, the entanglement generated by rotating black hole analogues, assessing the interaction between the Hawking effect and superradiance in full detail, and encoding it into new testable observables. I will then theoretically characterize these observables in terms of the relevant parameters for a polariton fluid experiment, such as the local properties of the flow, ambient thermal noise and detection losses -- decoherence --. I will also show how stimulating the polariton fluid with one-mode squeezed states enhances entanglement production by the ergoregion, thus optimizing the signal-to-noise ratio. The results of this theoretical project will shed light into the quantum properties of field theories and their entanglement structure. Thus, they will have a major impact in the fields of analogue quantum simulators, Quantum Field Theory in Curved Spa and, potentially, Relativistic Quantum Information.