[Todos] Coloquio Departamento de Física (hoy)

[pdmitruk en df.uba.ar]

Recordamos el coloquio de hoy,


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                        COLOQUIOS DEL DEPARTAMENTO DE FÍSICA FCEyN - UBA

                                 http://coloquios.df.uba.ar/

                                  Charla, café y galletitas
                        En el Aula Federman, 1er piso, Pabellón I,
                                 Ciudad Universitaria


                                Martes 2 de noviembre, 14hs,


                              Quantum turbulence simulations

                                      Marc Brachet

                             Laboratoire de Physique Statistique
                               Ecole Normal Superieure, Paris



The talk is about simulations of finite-temperature superfluids, using
the Truncated Gross-Pitaevskii Equation (TGPE). First, we will recall
the thermalization that is known to take place in the truncated Euler
equation for incompressible fluids. The statistical equilibria of the
(conservative) TGPE dynamics will then be characterized using an
algorithm based on a stochastically forced Ginzburg-Landau equation
(SGLE) that directly generates grand canonical distributions. A
standard finite-temperature second-order $\lambda$-transition will be
exhibited. A new turbulent mechanism of TGPE thermalization at small
scales through a direct cascade of energy will be demonstrated.
Dynamical counter-flow effects on vortex evolution will be
investigated using SGLE-preparated initial data and a dilatation of
vortex rings will be obtained for counter flows larger than their
longitudinal velocity.