Periodic Reporting for period 2 - QUANTIVIOL (Quantifying Quantum Gravity Violations of Causality and the Equivalence Principle)
Reporting period: 2019-03-01 to 2020-08-31
However, the price of restoring unitarity is steep: we must give up at least one of two other cherished principles. Either black holes must violate causality, allowing signals to travel faster than the speed of light. Or, they must violate the equivalence principle, the foundation of Einstein's theory of general relativity, and burn up infalling observers at their event horizon.
In this project, we will quantify, for the first time, the extent of this conflict. How large must the violations of causality or the equivalence principle be in order to rescue unitarity? And can these quantum gravity effects be measured observationally?