Selected Lectures around the World

The response of a gravitating object to an external tidal field is encoded in its Love numbers, which identically vanish for classical black holes in 4 spacetime dimensions. I will explain why for quantum black holes, generically, the Love numbers should be nonvanishing and negative, and show that their magnitude depends on the lowest lying collective excited levels of the quantum spectrum of the black hole.

The quantum state of the black hole

 XXXV Max Born Symposium, Wroclaw, Poland, 7 – 12 September 2015

If a black hole (BH) is initially in an approximately pure state and it evaporates by a unitary process, then the emitted radiation will be in a highly quantum state. As the purifier of this radiation, the state of the BH interior must also be in some highly quantum state. So that, within the interior region, the mean-field approximation cannot be valid and the state of the BH cannot be described by some semiclassical metric. On this basis, I will present a model in which the state of the BH interior is described as a collection of a large number of excitations that are packed into closely spaced but single-occupancy energy levels; a sort-of “Fermi sea” of all light-enough particles.

Black hole paradoxes: The clash of quantum mechanics and gravity

Given at: Arnold Sommerfeld Center, August 2014

Part 1

Part 3

Part 2

Part 4

Observable signal of gravity waves in the cosmic microwave background from small field models of inflation

Click HERE to watch

Given at: Perimeter Institute, June 2009