Dr. Peter ZimmermanJunior Scientist/Postdoc
I am interested in a broad range of topics in gravitational physics,
with a particular focus on problems having both astrophysical and
intrinsic theoretical significance.
Part of my research aims at unearthing novel nonlinear dynamics of nearly extremal black holes by studying quasinormal mode interactions. These modes carry astrophysical information about the mass and spin of the final remnants of binary mergers, and may be detected by advanced interferometers. Like many turbulent fluid systems, the perturbative spectrum of near-extremal black holes displays a family of weakly damped, highly collinear modes, which sum to yield a transient energy growth near the horizon. The physical mechanism for this effect is an emergent AdS near-horizon geometry which is “confining”. The confinement effectively lowers dissipation and is expected to lead to resonant couplings between the long-lived modes. I am currently studying the imprint of near-horizon conformal symmetry on these couplings and exploring astrophysical implications.
Another major component of my research is geared towards understanding the relativistic two-body problem in the regime where the mass ratio is small. These systems, which naturally form when a solar mass sized black hole or neutron star is captured into a bound orbit around a supermassive black hole, exhibit complex celestial dynamics with intricate features such as resonances. Furthermore, the trajectory of the small object deviates from a test-particle worldline due to its gravitational coupling to the field of the large black hole. The acceleration responsible for this deviation is produced by the so-called "self-force". Accurately modelling the effects of the self-force will be necessary for extracting the physical properties of gravitational sources for future space-based detectors.
My publications may be found here.
I completed my PhD in 2015 under the supervision of Dr. Eric Poisson at the University of Guelph. As a part of my thesis, I used worldline effective field theory to derive the gravitational self-force equations in nonvacuum spacetimes. I then went on to the University of Arizona as a postdoc with Dr. Samuel Gralla, where I worked to develop a critical-phenomena picture of the Aretakis instability of extremal black holes.