QUANTUM INVESTIGATIONS OF SPACE-TIME PROBLEMS

One can divide the discussion of the universe into two parts. First, there is the question of the local laws satisfied by the various physical fields. These are usually expressed in the form of differential equations. Secondly, there is the problem of the boundary conditions for these equations, and the global nature of their solutions. This involves thinking about the edge of space-time in some sense. These two parts may not be independent. Indeed it has been held that the local laws are determined by the large scale structure of the universe.

S. W. Hawking and G. F. Ellis, The large scale structure of space-time, Cambridge U press, 1980

The relation between boundary conditions and local laws, bulk and edges of spacetime,  mentioned in the short excerpt of the book of Hawking and Ellis shown above, lies at the hearth of  many crucial questions in quantum mecahnics and gravity theory: examples range from the irreversibility of time measurements to black-hole entropy. Concepts originally developed in quantum information, quantum optics and quantum many-body theory, such as entanglement and  quantum coherence may play a fundamental role to answer these questions framing gravity and quantum mechanics in a common theoretical farmework.

Joining the forces of researchers coming from different fields of quantum physics, our group  aims at studying these fundamental problems.

First image of a black hole obtained using Event Horizon Telescope observations of the center of the galaxy M87. Credit: Event Horizon Telescope Collaboration.

The sudden observability of black holes  achieved in 2016 by the LIGO  and VIRGO gravitational waves telescope and by the Event Horizon Collaboration has opened new pathways in gravity theory and it provides unprecedented tools to observe the boudaries of spacetime.