The possibility that our universe is not the only universe is one of the most polarizing theories in physics today. Speculative and controversial, this so-called multiverse proposal is suggested by the latest developments in cosmology and string theory, and is supported by some of the most regarded physicists. But are these theories rightly considered scientific? Is it possible to gather evidence that would support or refute the possibility that we inhabit a multiverse?
The World Science Festival’s annual salon series offers in-depth conversations with leading scientists, extending the discussion of the Festival’s premiere public programs to graduate students, postdocs, faculty and well-informed members of the general public.
Mario Livio is an internationally known astrophysicist at the Space Telescope Science Institute, which conducts the scientific program of the Hubble Space Telescope and will conduct the scientific program of the upcoming James Webb Space Telescope. He is a fellow of the American Association for the Advancement of Science. He has published more than 400 scientific papers on topics ranging from dark energy and cosmology to black holes and extrasolar planets. Livio is the author of five popular science books, including The Golden Ratio (for which he received the Peano Prize and the International Pythagoras Prize) and Is God a Mathematician? Livio’s recent book, Brilliant Blunders, was on the New York Times Best Sellers list and was selected by the Washington Post as one of the “2013 Best Books of the Year.”
Andreas Albrecht is a leading theoretical cosmologist. He received his Ph.D. from the University of Pennsylvania in 1983 where, with Paul Steinhardt, he wrote one of the original papers on “new” or “slow roll” inflation. Slow roll inflation has since become the dominant theory of the early universe and has passed numerous observational tests with flying colors. Deep puzzles remain regarding the theoretical underpinnings of cosmic inflation and Albrecht is a leading figure in this research area. The discovery of cosmic acceleration (often referred to as “the dark energy”) has been transformative to the field of cosmology and Albrecht is known for his groundbreaking work on dark energy theory and phenomenology. Albrecht moved from a professorship at Imperial College to UC Davis in 1998 to build the cosmology program there. He is now physics department chair at UC Davis. He is a fellow of both the American Physical Society and the Institute of Physics.
Raphael Bousso is recognized for discovering the general relation between the curved geometry of space-time and its information content, known as the “covariant entropy bound.” This allowed for a precise and general formulation of the holographic principle, which is believed to underlie the unification of quantum theory and Einstein’s theory of gravity. Bousso is also one of the discoverers of the landscape of string theory, which explains the small but non-vanishing value of the cosmological constant (or “dark energy”). His work has led to a novel view of cosmology, the multiverse of string theory. Bousso is currently professor of physics at the University of California, Berkeley.
Alan Guth is a professor of physics at MIT, and world-renowned for his discovery of inflationary cosmology, the dominant cosmological paradigm for over two decades. His current research focuses on developing mathematical tools for quantitatively analyzing inflation’s suggestion that there are an infinite number of universes.
Andrei Linde is a professor of physics at Stanford University, one of the authors of the inflationary theory and the theory of inflationary multiverse. He invented the theory of chaotic inflation, which is the most general form of inflationary cosmology. Linde also helped to develop the mechanism of vacuum stabilization in string theory, which helped to incorporate the theory of inflationary multiverse in the context of string theory. He is the author of the books Inflation and Quantum Cosmology and Particle Physics and Inflationary Cosmology. His honors include the Dirac Medal, Peter Gruber Prize, and the Fundamental Physics Prize.
Neil Turok is one of the world’s leading theoretical physicists. Formerly Professor of Physics at Princeton and Chair of Mathematical Physics at Cambridge, he is Director and Niels Bohr Chair at Perimeter Institute for Theoretical Physics in Waterloo, Canada. Turok’s research focuses on developing fundamental theories of cosmology and new observational tests. His predictions for the correlations of the polarization and temperature of the cosmic background radiation (CBR) and of the galaxy-CBR correlations induced by dark energy have been recently confirmed. With Stephen Hawking, he discovered instanton solutions describing the birth of inflationary universes. With Paul Steinhardt, he developed an alternative, cyclic cosmology, whose predictions are so far in agreement with observational tests. Turok founded the African Institute for Mathematical Sciences (AIMS), a network of five centres across Africa. For his scientific discoveries and his work founding and developing AIMS, Turok was awarded a TED Prize in 2008.