# Conférences publiques

- Val Kelly (CMS)
- Vojkan Jaksic (McGill University)

L'IAMP présentera deux conférences publiques gratuites destinées au grand public de la région de Montréal.

- Lundi 23 juil [symposia auditorium]
- 16:45 Rainer Weiss (Massachusetts Institute of Technology), Exploration of the Universe with Gravitational Waves
- Jeudi 26 juil [symposia auditorium]
- 16:45 Elliott Lieb (Princeton University), Facets of Entropy

**2017 Nobel Laureate**.

RAINER WEISS (NAS) is a Professor Emeritus at Massachusetts Institute of Technology (MIT). Previously Dr. Weiss served as an assistant physics professor at Tufts University and has been an adjunct professor at Louisiana State University since 2001. Dr. Weiss is known for his pioneering measurements of the spectrum of the cosmic microwave background radiation, his inventions of the monolithic silicon bolometer and the laser interferometer gravitational wave detector, and his roles as a co-founder and an intellectual leader of both the COBE (microwave background) Project and the LIGO (gravitational-wave detection) Project. He has received numerous scientific and group achievement awards from NASA, an MIT excellence in teaching award, the John Simon Guggenheim Memorial Foundation Fellowship, the National Space Club Science Award, the Médaille de l’ADION Observatoire de Nice, the Gruber Cosmology Prize, and the Einstein Prize of the American Physical Society. Dr. Weiss is a fellow of the American Association for the Advancement of Science, the American Physical Society, The American Academy of Arts and Sciences; and he is a member of the American Astronomical Society, the New York Academy of Sciences, and Sigma Xi. He received his B.S. and Ph.D. in physics from MIT. Dr. Weiss is a member of the NAS and has served on nine NRC committees from 1986 to 2007 including the Committee on NASA Astrophysics Performance Assessment; the Panel on Particle, Nuclear, and Gravitational-wave Astrophysics; and the Task Group on Space Astronomy and Astrophysics.Exploration of the Universe with Gravitational WavesThe observations of gravitational waves from the merger of binary black holes and from a binary neutron star coalescence followed by a set of astronomical measurements is an example of investigating the universe by "multi-messenger" astronomy. Gravitational waves will allow us to observe phenomena we already know in new ways as well as to test general relativity in the limit of strong gravitational interactions – the dynamics of massive bodies traveling at relativistic speeds in a highly curved space-time. Since the gravitational waves are due to accelerating masses while electromagnetic waves are caused by accelerating charges, it is reasonable to expect new classes of sources to be detected by gravitational waves as well. The lecture will start with some basic concepts of gravitational waves, then briefly describe the instruments and the methods for data analysis that enable the measurement of gravitational wave strains of the order of $10^{-21}$ and will then present the results of recent runs. The lecture will end with a vision for the future of gravitational wave astrophysics and astronomy.

ELLIOTT LIEB is an eminent American mathematical physicist and professor of mathematics and physics at Princeton University, who specializes in statistical mechanics, condensed matter theory, and functional analysis. In particular, his scientific works pertain to: the quantum and classical many-body problem, the stability of matter, atomic structure, the theory of magnetism, and the Hubbard model. He is a prolific author in mathematics and physics with over 300 publications. He received his B.S. in physics from MIT (1953) and his Ph.D. in mathematical physics from the University of Birmingham in England (1956). Lieb was a (1956–1957) Fulbright Fellow at Kyoto University, Japan, and for some time worked as the Staff Theoretical Physicist for IBM. He has been a professor at Princeton since 1975, following a leave from his professorship at MIT. Lieb has been awarded several prizes in mathematics and physics, including the 1978 Heineman Prize for Mathematical Physics of the American Physical Society and the American Institute of Physics (1978), the Max Planck Medal of the German Physical Society (1992), the Boltzmann medal of the International Union of Pure and Applied Physics (1998), the Schock Prize (2001), and the Henri Poincaré Prize of the International Association of Mathematical Physics (2003). He is a member of the U.S. National Academy of Sciences and has twice served (1982–1984 and 1997–1999) as the President of the International Association of Mathematical Physics. His Erdős number is 2. He is married to fellow Princeton professor Christiane Fellbaum.

Facets of EntropyI will discuss and compare several ways in which the word entropy is used and the confusion that is sometimes generated. For example, to what extent is entropy well-defined outside of equilibrium and what does it mean for systems that have no thermodyamic limit? Does statistical mechanics define the concept and does it have an independent meaning outside of the self-referential concepts temperature and heat? A simple definition of entropy for macroscopic systems by Jakob Yngvason and myself that makes no mention of heat, temperature, and Carnot cycles will be described briefly.