Coloquio - Daniel Parisi - Atascos en flujo de partículas: Desde material granular a egreso de peatones
- 2020-07-16 14:00 |
- Vivo en YouTube
Investigador Principal - CONICET
Effects arising from quantum fluctuations of charge and electromagnetic radiation, with emphasis on the study of quantum fluctuations and Casimir interactions between micro or macroscopic objects. In particular, we study the detailed quantitative behavior of Casimir forces in situations involving nontrivial geometries that have both conceptual interest and eventual applications in nanotechnology. With the advent of microfabricated structures (atom chips) that enable one to confine small numbers of neutral atoms near dielectric surfaces, we are able to study atom-surface (Casimir-Polder) interactions in great detail. Dispersion forces such as Casimir forces between bodies, Casimir-Polder forces between atoms and bodies and van der Waals forces between atoms are effective electromagnetic forces that arise as consequences of correlated ground-state fluctuations. We are investigating dispersion forces in and out of thermal equilibrium; influence of new materials, such as graphene, and quantum friction.
Nonadiabatic time-dependent external conditions can excite any quantum system. In the context of quantum field theory, the initial vacuum state generally evolves into an excited state with a nonvanishing number of particles. For example, time-dependent gravitational or electromagnetic fields can induce particle creation. The same phenomena take place in the presence of time-dependent environments, as, for instance, a cavity with time-dependent size or electromagnetic properties. The latter type of situations are broadly named “dynamical Casimir effect” (DCE). We investigate DCE performing analytical approximations and also exact numerical apporaches.
Geometric phases (GPs) can be only observed in experiments carried out in a time scale slow enough to ignore nonadiabatic corrections, but rapid enough to avoid the destruction of the interference pattern by decoherence. The purpose of this plan is to study how GPs are affected by decoherence. Not only shall we analyze the effect of the environment on the GPs and their robustness against decoherence, but also under which conditions GPs can be measured. GPs for entangled states and non-Markovian effects are also of particular interest.