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

Our understainding of superradiance regards it as a phenomenon of classical amplification. Leveraging techniques from QuantumField Theory in Curved Spacetimes and Gaussian quantum information, I will provide a theoretical proof that superradiancegenerates entanglement and is inherently quantum, calling for a revision of the current paradigm. It is believed that a horizonlesssystem displaying rotational superradiance is unstable. Given that horizons generate Hawking radiation, this prevents the study ofsuperradiance in isolation from the latter, which also generates entanglement and hinders a clean observation of our novelprediciton. I propose to overcome this difficulty through dissipative dynamics. Polariton fluids are dissipative quantum fluids thatallow for homodyne detection, thus being ideal platforms to test our predictions. I will quantify the entanglement generated by anisolated ergoregion in a rotating polariton fluid, and characterize it as a function of relevant experimental parameters. I will follow byextending our methods to quantify, for the first time, the entanglement generated by rotating black hole analogues, assessing theinteraction between the Hawking effect and superradiance in full detail, and encoding it into new testable observables. I will thentheoretically characterize these observables in terms of the relevant parameters for a polariton fluid experiment, such as the localproperties of the flow, ambient thermal noise and detection losses -- decoherence --. I will also show how stimulating the polaritonfluid with one-mode squeezed states enhances entanglement production by the ergoregion, thus optimizing the signal-to-noiseratio. The results of this theoretical project will shed light into the quantum properties of field theories and their entanglementstructure. 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.