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Nombre de programmes trouvés : 89
Conférences

le (1h17m54s)

The dark Universe

Over the past few decades it has become clear that most of the mass in the Universe is in an unseen form we call dark matter. I will present the observational evidence leading to this remarkable realization and then focus in particular on the tool of gravitational lensing and how we can use lensing to study the distribution of matter in the universe. I will finish my talk with a discussion of the discovery of dark energy and discuss possibilities for what this mysterious ’energy’ might be.by Laura Parkerhttps://www.procyon.espci.fr/fr/Conferences/The-dark-Universe.html
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Conférences

le (1h4m15s)

QUASARS : DES PHARES DANS LE NOIR

Les quasars sont des sources extrêmement lumineuses que l'on arrive à détecter à des distances cosmologiques. Ceux-ci peuvent servir de phares pour détecter la matière aux confins de l'Univers, interposée entre les quasars et nous, du milieu intergalactique jusqu'au sein de galaxies. Après une présentation de cette technique d'observation un peu particulière, je présenterai différentes avancées dans ce domaine et quelques-uns des défis qui nous attendent dans les années à venir.
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Conférences

le (1h6m39s)

MEASUREMENT OF THE THERMAL SPECTRUM OF HAWKING RADIATION FROM AN ANALOG HORIZON

Hawking predicted that black holes should radiate thermal radiation, the temperature being a function solely of the geometry near the horizon of the black hole. The same arguments show that one would also expect thermal radiation from other horizons, like the sonic horizon formed in a trans-sonic flow, or the horizon to fluid surface gravity waves formed by a blocking flow.This talk will discuss the phenomenon of black hole thermal emission, problems with its derivation, the ubiquity of such thermal emission by horizons, and the measurements ...
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Conférences

le (53m57s)

USING GENERAL RELATIVITY TO STUDY CONDENSED MATTER

It has recently been shown that in addition to describing black holes, gravitational waves, and other gravitational phenomena, general relativity can also describe aspects of nongravitational physics including condensed matter. This is a result of a remarkable gauge/gravity duality that has emerged from string theory. I will explain this surprising development and illustrate it by showing how general relativity can reproduce aspects of superconductivity. It can even reproduce novel aspects of the mysterious high temperature superconductors.
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Conférences

le (1h8m17s)

TWEAKING GENERAL RELATIVITY: MOND RELATIVISTIC GRAVITY THEORY AS A SUBSTITUTE FOR DARK MATTER

The success of the standard concordance cosmological model in predicting the primordial abundances of the light elements, and modeling the power spectrum of fluctuations of the cosmic microwave background have suggested to many that its ingredients are all one needs to understand galaxies and galaxy systems. However, a number of known problems with this expectation may signal the failure of standard gravity theory already on galaxy scales. An alternative nonrelativistic gravity theory - AQUAL, suggested by the phenomenological MOND paradigm, does rather well for ...
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Conférences

le (1h3m38s)

THE WARPED SIDE OF THE UNIVERSE: NUMERICAL RELATIVITY, GRAVITATIONAL WAVES AND MACROSCOPIC QUANTUM MECHANICS

There is a "Warped side" to our universe, consisting of objects and phenomena that are made solely or largely from warped spacetime. Examples are black holes, singularities (inside black holes and in the big bang), and cosmic strings. Numerical-relativity simulations are revolutionizing our understanding of what COULD exist on our universe's Warped Side; and gravitational-wave observations (LIGO, VIRGO, LISA, ...) will reveal what phenomena actually DO exist on the Warped Side, and how they behave.To detect the gravitational waves and extract their information, in ...
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