Line of research overview

Analogue Gravity

Principal Investigator: Stefano Liberati

Abstract: Condensed matter systems, such as acoustics in flowing fluids, light in moving dielectrics, or quasiparticles in a moving superfluid, can be used to mimic aspects of curved spacetime geometries and of fields propagation over them. For example a fluid flow with a supersonic region can mimic a black hole for phonons in the fluid (what is called an acoustic black hole). In this sense these systems (and others) provide experimentally accessible models of curved-space quantum field theory and of the phenomenology one could expect if spacetime would be an intrinsically emergent object. In this sense analogue gravity system can play a manifold purpose: on the one side they can provide a test bed for relevant phenomena in astrophysics such superradiance and cosmological particle creation or they can help shedding light and reproduce in laboratory evanescent phenomena like Hawking radiation from black holes. Also, some of them can be used as quantum simulators of interesting phenomena in particle physics and relativistic quantum information, as well as toy model of emergent gravity scenarios.

Status of project and perspectives: The research of the project in the past years has been focussed mainly on analogue black holes. In particular we have explored the information loss problem associated to analogue Hawking radiation in a generalised setting able to take into account analogue quantum gravitational degrees of freedom. Also we have considered the back reaction of Hawking radiation in such an analogue setting, verifying how in spite of different geometrodynamical equation it may present some similarities with the general relativistic phenomenology, able to provide important lessons concerning these long standing problems in gravitational theory. We hope in the future to connect these results to experimental settings and to concrete quantum gravity models.