Tuesday 26 September 2017, 16:30 at UPMC, Amphithéâtre Charpak	CPMC (Colloquium Pierre et Marie Curie)	astro-ph
Ewine Van Dishoeck ( Leiden Observatory )	Building stars, planets and the ingredients for life in space
Abstract:	One of the most exciting developments in astronomy is the discovery of thousands of planets around stars other than our Sun. But how do these exo-planets form, and why are they so different from those in our own solar system? Which ingredients are available to build them? Thanks to powerful new telescopes, especially the Herschel Space Observatory and the Atacama Large Millimeter Array (ALMA), astronomers are starting to address these age-old questions scientifically. Stars and planets are born in the cold and tenuous clouds between the stars in the Milky Way, and ALMA allows us to zoom in on planetary construction zones for the first time. Water and a surprisingly rich variety of organic materials are found, including simple sugars. Can these pre-biotic molecules end up on new planets and form the basis for life elsewhere in the universe?
Attachments:	AfficheEwineDishoeck.pdf (3350634 bytes)

Thursday 28 September 2017, 11:00 at LPTHE, Bibliothèque	SEM-INFOR (Séminaire informel)	cond-mat.stat-mech
Camille Aron ( LPTENS )	(Non) equilibrium dynamics: a (broken) symmetry
Abstract:	It is fascinating that most many-body systems, if unperturbed, tend to relax towards thermal equilibrium. I will discuss a recent result showing that quantum equilibrium dynamics can be elevated to the rank of a universal (model-independent) symmetry of Keldysh field theories. This fundamental symmetry imposes strong constraints on the equilibrium correlation functions. But more importantly, this allows to study non-equilibrium dynamics as symmetry-breaking processes, providing important clues on the so-far poorly understood production of entropy in quantum mechanical systems.

Thursday 5 October 2017, 10:00 at IHP, 314	RENC-THEO (Rencontres Théoriciennes)	hep-th
Pierre Vanhove ( CEA Saclay )	TBA

Thursday 5 October 2017, 11:00 at LPTHE, Bibliothèque	SEM-LPTHE (Séminaire du LPTHE)	cond-mat.stat-mech|hep-th|math-ph
Jean-Bernard Zuber ( LPTHE )	Horn's problem, from classical to quantum
Abstract:	Horn's (classical) problem deals with the following question: what can be said about the spectrum of eigenvalues of the sum C=A+B of two Hermitian matrices of given spectrum ? Curiously this problem is intimately related to the "quantum" problem : given two irreducible representations of SU(n), which irreps appear in their tensor product ? The support of the spectrum of C is well understood, after a long series of works from Weyl (1912) to Knutson and Tao (1999), and the classical problem is known to provide an asymptotic approach of the quantum one. Here I show how an explicit computation based on a well-known matrix integral enables one to determine the probability distribution of the eigenvalues of C, and sheds some new light on the relation between the classical and quantum problems.

Thursday 5 October 2017, 11:30 at IHP, 314	RENC-THEO (Rencontres Théoriciennes)	hep-th
Bruno Le Floch ( Princeton )	TBA