Professor and Third Year Coordinator
Telephone: 519-824-4120 x53653
Office: MacN 452
Online: Research Page
I obtained a BSc degree in physics from Laval University in 1987, a MSc degree in theoretical physics from the University of Alberta in 1989, and a PhD in theoretical physics from the University of Alberta in 1991. My thesis work was carried out under the supervision of Werner Israel; the topic was the internal structure of black holes.
After obtaining my PhD I spent three years (1991-1994) as a post-doctoral fellow at the California Institute of Technology, where I worked under the supervision of Kip Thorne. And before coming to Guelph in 1995, I spent a year (1994-1995) at Washington University in St. Louis, working under the supervision of Clifford Will.
Professional Activities & Awards
I am a member of the Editorial Board (Divisional Associate Editor for Astrophysics) of the prestigious research journal Physical Review Letters.
I am a member of the Editorial Board of Classical and Quantum Gravity, a leading publication in the field of gravitational physics.
In 2008 I was elected Fellow of the American Physical Society, “for important contributions to the theory of gravitational radiation from compact bodies orbiting black holes, to the theory of back-reaction of the emitted radiation on their motions, and to understanding the implications for gravitational-wave detection.\"
In 2007 I was elected to the Committee of the International Society on General Relativity and Gravitation, for the period 2007-2010.
In 2006 I was elected as an officer of the Topical Group in Gravitation of the American Physical Society. I am a member at large of the executive committee for the period 2007-2010.
In 2005 I was awarded the Herzberg Medal by the Canadian Association of Physicists, for outstanding achievement by a physicist aged 40 or less.
I am an affiliate member of the Perimeter Institute for Theoretical Physics, a privately funded research institute based in Waterloo, Canada.
KEYWORDS: Gravitational physics, general relativity, black holes, compact objects, gravitational waves, self-force
My research activities have recently been divided into two broad streams. The first stream is concerned with the physics of black holes in tidal environments. The second stream is concerned with the gravitational self-force. The context for this work is provided by the ongoing effort to measure gravitational waves using earth-based detectors (now operational) and space-based detectors (in development). Gravitational waves are produced when astronomical bodies are accelerated to high speeds; binary systems of compact objects (such as supermassive black holes, solar-mass black holes, and neutron stars) are among the most promising sources. My research aims to improve our understanding of such systems, and refine our predictions regarding the form that the gravitational-wave signals will take.
Black holes in tidal environments
What happens to a black hole when it is not isolated, but placed in the presence of other bodies which exert tidal forces on it? To answer this question requires a description of the tidal environment, a computation of the gravitational perturbation created by the external bodies, and the extraction of physical, measurable consequences. Among the most exciting of those is the effect of the tidal coupling on the phasing of gravitational waves emitted by the system of moving bodies; a measurement of this effect will allow a black hole to be observationally distinguished from other types of compact bodies.
The term “gravitational self-force'' refers to the motion of a small-mass body around a large black hole, in a treatment that goes beyond the test-mass description. In this treatment, the small mass creates a (small but significant) perturbation in the gravitational field of the large black hole. The perturbation affects the motion of the small body --- the motion is no longer geodesic, but accelerated, and the body is said to move in response to its own gravitational self-force. The perturbation also propagates outward in the form of gravitational waves. What is the nature of the self-forced motion? What information concerning the strong-field dynamics can be extracted from the gravitational waves? These are the questions that my research group and I have been exploring.