Jul 5 – 10, 2021
Europe/Rome timezone

Physical black holes in semiclassical gravity

Jul 6, 2021, 6:30 AM
Talk in the parallel session Theoretical and observational studies of astrophysical black holes Theoretical and Observational Studies of Astrophysical Black Holes


Sebastian Murk (Macquarie University, Sydney)


Assuming only the existence of an apparent horizon and its regularity, we derive universal properties of the near-horizon geometry of spherically symmetric black holes. General relativity admits only two distinct classes of physical black holes, and both appear at different stages of the black hole formation. Using a self-consistent semiclassical approach, we find that the resulting near-horizon geometry differs considerably from the one that is obtained using classical notions of a horizon. If semiclassical gravity is valid, then accretion after horizon formation inevitably leads to a firewall that violates quantum energy inequalities. Consequently, physical black holes can only evaporate once a horizon has formed. Comparison of the required energy and time scales with the known semiclassical results suggests that the observed astrophysical black holes are horizonless ultra-compact objects, and the presence of a horizon is associated with currently unknown physics. This has interesting implications for the information loss paradox.

Note: the results presented in this talk are summarized in Phys. Rev. D 103, 064082 (2021).

Primary author

Sebastian Murk (Macquarie University, Sydney)


Dr Daniel Terno (Macquarie University)

Presentation materials

There are no materials yet.