General Relativity & Quantum Cosmology

Among the discoveries in LIGO/Virgo/KAGRA's third observing run are a handful of compact binary coelescences (CBCs) that stand out for one reason or another -- exceptional either because they were the first entry in a previously undetected class of CBCs, or because of the mass, mass ratio, or spins of their component compact objects. After briefly discussing the implications of these observations and their merger rates, I will focus on the tension that has arisen from the discovery of the most massive binaries in LVK's catalog. These binaries have component black holes encroaching on the pair-instability mass gap, where black holes are not expected to be formed directly from stars. I'll discuss an alternate formation channel, where massive black holes are assembled dynamically from repeated binary black hole mergers, and an analysis that constructs a binary black hole population that allows for hierarchical formation in both globular cluster-like and nuclear star cluster-like environments.

Zoom Link: https://pitp.zoom.us/j/94867401133?pwd=bTJmVy8vUk9rb1RvTDlrMzl1ZHdEZz09

The analogue gravity framework uses condensed matter systems to simulate phenomena characteristics of quantum field theory in curved spacetimes (e.g. cosmological particle production or black hole evaporation). In this seminar, I will review the state of this field and explore its extension towards the simulation of the emergent spacetime paradigm. In doing so I will discuss three lessons that we can draw from this framework about long standing puzzles in black hole thermodynamics and cosmology.

Zoom Link: https://pitp.zoom.us/j/98714282554?pwd=QnAxRkk4SVg0TnVneDFySFJYTDJoQT09

The first direct detection of gravitational waves from merging black holes in 2015 has opened up new avenues to studying gravity in the strong-field regime, inferring the mass and spin distributions of astrophysical black holes and probing the nature of ultra-dense nuclear matter in the interior of neutron stars. Seven years on, we count approximately 100 detections of gravitational waves from compact binary mergers.
 
These observations are goldmines for precise measurements of the source properties and the discovery of new physics at the edge of our current understanding. Pioneering innovations in detector technology will soon let us put black holes under a microscope, allowing us to push Einstein's theory of gravity to the limit. To do so will require exquisitely accurate theoretical models for the emitted gravitational-wave signal if we are to unlock the full discovery potential.

In this talk, I will discuss some of the most spectacular discoveries from the third observing run of Advanced LIGO and Virgo and their implications. I will also highlight some of the pitfalls and challenges in interpreting gravitational-wave detections.

Zoom Link: https://pitp.zoom.us/j/96161151229?pwd=NExyMitMaWpMTVBsL0VRTjZNbFBvZz09