Année 2012 - 2013

Jeudi 30 mai 2013 According to Hund (1927) quantum mechanics forbids the existence of stable optically active (chiral) molecules as they violate the invariance under parity of the Hamiltonian. This paradox has attracted much attention ever (...) | ↦ Lire la suite

Jeudi 23 mai 2013 It has been known for some time that a system with a filled band will have an integer quantum Hall conductance equal to its Chern number, a toplogical index associated with the band. While this is true for a system in a (...) | ↦ Lire la suite

Jeudi 16 mai 2013 Mean-field electrodynamics was conceived as a model of dynamo action on large scales due to small scale velocity fields. The model equations for the mean field, which can give growing solutions in axisymmetric geometries (...) | ↦ Lire la suite

Jeudi 25 avril 2013 The laws of thermodynamics need to be generalized to the finite, quantum, non-equilibrium domain. It is by no means clear how to achieve this. In particular, how exactly are we to phrase the concepts of heat, work and (...) | ↦ Lire la suite

Jeudi 18 avril 2013 This year, Bohr’s model of the Hydrogen atom is 100 years old. Height years after Einstein showed that light is quantized and introduced the concept of photons, the young Danish physicist announced in 1913 that matter too (...) | ↦ Lire la suite

Jeudi 11 avril 2013 Sketched out in 1992, selected by ESA in 1996, launched in 2009, Planck will have delivered on March 21st its first full sky maps of the millimetric emission at 9 frequencies, as well as those which follow from them, and in (...) | ↦ Lire la suite

Jeudi 4 avril 2013 We face one of the biggest challenges of the 21st century : providing more and more energy to meet rising demand, but keeping it affordable, secure, reliable and sustainable. But ‘sustainable’ means different things to (...) | ↦ Lire la suite

Jeudi 28 mars 2013 Contrary to common perception topological fluid mechanics is an old subject, rooted in Helmholtz’s (1858) conservation laws and Kelvin’s (1870) vortex atom theory. In this talk we would like to address some of the most (...) | ↦ Lire la suite

Jeudi 14 mars 2013 Magnetic monopoles were first proposed to exist by Dirac many decades ago as the natural counterparts of electrically charged particles such as the electron. Despite much searching, no elementary monopoles have ever been (...) | ↦ Lire la suite

Jeudi 28 février 2013 About thirty years have passed since the standard model of particle theory is established. It is considered to describe three of the fundamental interactions correctly, that is, the electromagnetic, weak and strong (...) | ↦ Lire la suite

Jeudi 21 février 2013 Flocking is a paradigmatic example of self-organized collective behaviour, where collective ordering emerges from the mutual interactions between individuals. In this respect, it shares striking similarities with (...) | ↦ Lire la suite

Jeudi 7 février 2013 Glass-workers shape marvelous objects without using moulds or precise temperature control because glass is a unique material that transforms from liquid to solid in a very progressive way. Can we imagine other compounds (...) | ↦ Lire la suite

Jeudi 31 janvier 2013 Gauge/gravity duality is a conjectured correspondence between certain strongly coupled quantum field theories in 3 or 4 space-time dimensions, and theories of general relativity in higher dimensions. The duality was (...) | ↦ Lire la suite

Jeudi 24 janvier 2013 The development of an organism from egg to adult has fascinated scientists for centuries. In the past several decades, genetics has been very successful in attaching a function to hundreds of genes whose mutation can (...) | ↦ Lire la suite

Jeudi 17 janvier 2013 Using modern micro and nano-fabrication techniques combined with superconducting materials we realize quantum electronic circuits. We create, store, and manipulate individual microwave photons on chip. The strong (...) | ↦ Lire la suite

Jeudi 10 janvier 2013 In many functionally distinct regions of the brain, populations of neurons form maps of sensory and cognitive spaces. In this talk, I will explain a physicist’s approach to the neural topography of information. First, I (...) | ↦ Lire la suite

Jeudi 20 Décembre La détection, l’identification et la quantification, locale ou à distance de polluants et de substances nocives d’origines naturelle ou anthropique sont primordiales pour le contrôle de la qualité de l’air. La mesure de ces gaz, (...) | ↦ Lire la suite

Jeudi 13 décembre The ATLAS and CMS experiments operating at the CERN-LHC have published this summer the discovery of a new particle which, so far, behaves like the long-sought Higgs boson of the Standard Model of Particle Physics. The role (...) | ↦ Lire la suite

Jeudi 6 décembre Quantum information requires quantum-mechanical systems with both long coherence times and that can be easily coupled together in order to perform quantum logic operations. NV centers are color centers in a diamond crystal, and (...) | ↦ Lire la suite

Jeudi 29 novembre Under suitable conditions, first order phase transitions such as the freezing of a liquid or the structural transformation of a solid occur via a nucleation and growth mechanism, in which a nucleus of the stable phase is (...) | ↦ Lire la suite

Jeudi 22 novembre We are carrying out studies of coherent quantum phase slip (CQPS) effect which is the exact quantum mechanical conjugate to the Josephson effect. It is a phenomenon involving coherent tunneling of magnetic flux across a (...) | ↦ Lire la suite

Jeudi 15 novembre Massive black holes, weighing millions to billions of solar masses, inhabit the centers of today’s galaxies. The progenitors of these black holes powered luminous quasars within the first billion years of the Universe. The (...) | ↦ Lire la suite

Jeudi 8 novembre The ability to read the sequence of genes and genomes has transformed the face of biology. However, as part of the copying, storage, transfer and reading of the genetic information they harbor, genomes are subject to (...) | ↦ Lire la suite

Jeudi 25 octobre The non profit organization Paris-Montagne mobilizes scientific community to create new kinds of science communication. The aim is to give opportunity to youngsters from underpriviledged areas to discover science and (...) | ↦ Lire la suite

Jeudi 18 octobre In a few words, microfluidics is the science of manipulation of fluids at the micrometric scale. Microfluidics relies on a diversity of technologies that have led, over the last decade, to produce new objects, interesting (...) | ↦ Lire la suite

Jeudi 11 octobre Numerous functional processes in condensed matter involve atomic motions and charge relocations on ultrashort time scales. X-ray diffraction methods with a femtosecond time resolution allow for spatially resolving transient (...) | ↦ Lire la suite

Jeudi 4 octobre I will give a short pedagogical introduction to the modern physical cosmology. The evolution of the expanding homogeneous universe will be considered including its thermal history, with particular stress of recombination epoch (...) | ↦ Lire la suite

Jeudi 27 septembre I will give a short pedagogical introduction to the modern physical cosmology. The evolution of the expanding homogeneous universe will be considered including its thermal history, with particular stress of recombination (...) | ↦ Lire la suite