Field: Physics

Field: Physics

Research Expertise:
cosmology, general relativity, gravitational waves, gravity, theoretical physics

Expert: Dr. Valerio Faraoni
Department: Physics
Interview languages: English

Photo of Dr. Valerio Faraoni

Dr. Valerio Faraoni

Full Professor

Valerio Faraoni earned a BSc in Physics (Laurea in Fisica) at the University of Pavia, Italy, and an MSc and PhD (1991) in Astrophysics under the supervision of Prof. George F.R. Ellis at the International School for Advanced Studies in Trieste, Italy (https://www.sissa.it). He has held various research and teaching appointments at the University of Victoria, B.C., the Inter-University Centre for Astronomy and Astrophysics in Pune, India, the Free University of Brussels, Belgium, and the University of Northern British Columbia. He came to Bishop's University in 2005, where he is currently a Professor in the Department of Physics & Astronomy.Contact Information
Phone: 819-822-9600 ext. 2490

Valerio Faraoni earned a BSc in Physics (Laurea in Fisica) at the University of Pavia, Italy, and an MSc and PhD (1991) in Astrophysics under the supervision of Prof. George F.R. Ellis at the International School for Advanced Studies in Trieste, Italy (https://www.sissa.it). He has held various research and teaching appointments at the University of Victoria, B.C., the Inter-University Centre for Astronomy and Astrophysics in Pune, India, the Free University of Brussels, Belgium, and the University of Northern British Columbia. He came to Bishop’s University in 2005, where he is currently a Professor in the Department of Physics & Astronomy.

Research

Theoretical Cosmology: Dark Energy and Modified Gravity

Theoretical cosmology studies the dynamics, origin, evolution, and fate of the universe, and the formation of structures (galaxies, galaxy clusters, and superclusters) in it. In 1998 it was discovered, by studying distant supernovae, that the expansion of the universe is accelerated. Many theoretical models have been proposed in order to explain this shocking discovery and they mostly fall into two classes: dark energy and modified gravity. Dark energy models assume that Einstein’s theory of gravity (general relativity) is valid and that a mysterious form of dark energy of unknown nature permeates the universe and makes up 70% of its energy content. This dark energy must necessarily have exotic properties, such as a negative pressure. The current observational data seem to require an even more negative pressure and more exotic energy (called phantom energy), which may cause the universe to end at a finite time in the future in a Big Rip singularity (the end of time), in which all bound objects-galaxies, planets, humans, atoms-are ripped apart by increasing gravitational forces. If phantom energy is really fuelling the cosmic acceleration, we probably have to abandon Einstein’s general relativity in favour of alternative gravity theories such as, for example, scalar-tensor gravity, a generalization of Einstein’s theory.

The second class of models, modified gravity, does not require exotic dark energy but instead modifies Einstein’s relativity with corrections that only affect large (cosmological) scales.

Dr. Faraoni’s research explores both classes of models, trying to fully understand their dynamics, explain the cosmic acceleration, develop models that are theoretically consistent and compatible with available experiments, study their predictions (e.g., will the universe accelerate forever? Will it end in a Big Rip?) and related issues such as the production of gravitational waves, or the accretion of phantom energy onto black holes or wormholes. Long term goals include the development of the correct theory of gravity (it is possible that departures from Einstein’s gravity are unobservable at the small Solar System scales but are already observed in the cosmic acceleration), finding out if dark energy actually exists and, if so, determining precisely its strange properties, understanding the early universe and obtaining information, otherwise inaccessible on Earth, on the high energy physics that left an imprint in the cosmic microwave background and in the distribution of galaxies and galaxy clusters.

Other interests include the study of black holes embedded in a cosmological background, foundations and possible violations of the Equivalence Principle (the basis of relativistic gravity) in high energy physics, and the thermodynamics of spacetime.

Dr. Faraoni collaborates with many researchers worldwide on the subjects above.

Details on his research and an up-to-date list of publications can be found on Google Scholar.

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Research Expertise:
astronomy, astrophysics, binary stars, cosmology, light pollution, observatories, physics

Expert: Dr. Lorne Nelson
Department: Physics
Interview languages: English

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Dr. Lorne Nelson

Full Professor

Professor Nelson received his Ph.D. in 1984 in the area of theoretical astrophysics (cannibalistic binary interactions). He subsequently held a postdoctoral fellowship at MIT (Center for Space Research) that led to pioneering work on the structure and evolution of a completely new class of substellar objects known as Brown Dwarfs. From 1986-1988 he was a research fellow at CITA (Canadian Institute of Theoretical Astrophysics). He joined the department of physics at Bishop's as an Assistant Professor in 1988 and became a Full Professor in 1998. In 1995 he won the Chancellor's Prize for teaching and he is currently a Canada Research Chair in Astrophysics.…Contact Information
Phone: 819-822-9600 ext. 2372

Professor Nelson received his Ph.D. in 1984 in the area of theoretical astrophysics (cannibalistic binary interactions). He subsequently held a postdoctoral fellowship at MIT (Center for Space Research) that led to pioneering work on the structure and evolution of a completely new class of substellar objects known as Brown Dwarfs. From 1986-1988 he was a research fellow at CITA (Canadian Institute of Theoretical Astrophysics). He joined the department of physics at Bishop’s as an Assistant Professor in 1988 and became a Full Professor in 1998. In 1995 he won the Chancellor’s Prize for teaching and he is currently a Canada Research Chair in Astrophysics.

Website

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Research Expertise:
general relativity, gravitation, cosmology, quantum theory, black holes, dark matter, quantum field theory, entropy

Expert: Dr. Fayçal Hammad
Department: Physics
Interview languages: English, French

Photo of Dr. Fayçal Hammad

Dr. Fayçal Hammad

Adjunct Professor

Fayçal Hammad earned a BSc, as well as an MSc, in the Physics of Materials and Electronic Components at the University of Bejaia, Algeria, and a Doctorate degree in Theoretical Physics from the same University. He worked as an Assistant Professor of Physics and Mathematics at the University of Bejaia before joining Champlain College and Bishop’s University in 2014.Contact Information
Phone: 819-822 9600 ext. 2228

Fayçal Hammad earned a BSc, as well as an MSc, in the Physics of Materials and Electronic Components at the University of Bejaia, Algeria, and a Doctorate degree in Theoretical Physics from the same University. He worked as an Assistant Professor of Physics and Mathematics at the University of Bejaia before joining Champlain College and Bishop’s University in 2014.

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