IPhT

Un site dédié a été mis en place:
http://portail.intra.cea.fr/projet-organisme

Attention, il faut d’abord se connecter à l’intra.

Les contributions peuvent être anonymes.
communiqueinterne-projetdorganisme.pdf

This past year a team at IPhT around John Joseph Carrasco — in collaboration with physicists at UCLA and Penn State University in the United States, and Uppsala University in Sweden — completed a calculation long thought to be impossible: the direct understanding of the dimensions of space-time in which the most symmetric particle-based field theory of gravity (maximal supergravity) would cease to be predictive when quantum effects are relevant. One can isolate order by order the quantum effects in graviton scattering. For two gravitons scattering off of each other, this calculation required consideration of the fifth-order quantum correction. This puts strong constraints on the behavior of fundamental symmetries in controlling the high-energy behavior of this theory.
 
To give an idea of the size of the problem, consider a word count of everything ever written by human beings (from cuneiform tablets and stone carvings to books, magazines, emails, etc). This was estimated at one time to be some 40 quadrillion words. ...

Periodically driven quantum many-body systems (such as cold atoms in time-dependent optical lattices and quantum materials under ultra-fast optical excitation) offer exciting perspectives of exploring quantum phases of matter along genuine non-equilibrium pathways.This so-called Floquet engineering relies, however, on the suppression of heating, i.e. the uncontrolled energy absorption from the drive. This was known to be the case only in the limit of extremely high frequency,thus limiting its practical use.

A team at IPhT around Francesco Peronaci, Marco Schiro and Olivier Parcollet showed that also strong electronic interactions can largely circumvent energy absorption, and thus provide a robust
platform for Floquet engineering even at finite frequency. This is demonstrated with non-equilibrium dynamical mean-field calculations
on a driven Fermi-Hubbard model, a paradigmatic example of lattice correlated electrons. ...