Session B10: A Beginner's Guide to Gravitational Physics

A Beginner's Guide to Numerical Relativity

In this tutorial session I will give an overview of numerical solution of the Einstein field equations from the perspective of the Cauchy initial value problem. I will focus on difficulties central to general relativity, in particular the constraints, coordinate freedom, and singularities, and how they have been overcome for binary merger simulations. I will close with an example of an open problem where some of these challenges have yet to be solved : the interior structure of rotating  black holes formed by gravitational collapse.   

A Beginner's Guide to Quantum Gravity, Entanglement, and Information

In this beginner's guide, we discuss how the entanglement entropy of geometric observables provides a probe of locality and semiclassicality in quantum gravity. We use the quantum polyhedron and intertwiner space as a model system that allows us to illustrate concretely this connection.   

A Beginner's Guide to Gravitational Wave Detection with Pulsar Timing Arrays

Pulsar timing arrays are sensitive to low-frequency gravitational waves with periods of months to decades, such as those emitted by supermassive binary black holes at subparsec separations. They do so by precisely timing a collection of millisecond pulsars, whose extremely stable rotation makes them ideal for measuring perturbations in spacetime. Gravitational waves induce correlations in the pulse arrival times that follows a characteristic pattern known as the Hellings-Downs curve. Recently, pulsar timing array experiments around the world published the first evidence of nanohertz gravitational waves. In this talk, I will discuss how pulsar timing arrays detect gravitational waves, how we construct pulsar timing arrays, and some of the challenges in extracting gravitational wave signals from pulsar observations.