Fractional diffusion of cold atoms in optical lattices

Seminar
Speaker
Eli Barkai
Date
05/01/2015 - 14:00 - 12:30Add to Calendar 2015-01-05 12:30:00 2015-01-05 14:00:00 Fractional diffusion of cold atoms in optical lattices Fractional calculus is an old branch of mathematics which deals with fractional order derivatives. Recently the Davidson's group (Weizmann) has recorded the spatial diffusion of cold atoms in optical lattices, fitting the results to the solution of a fractional diffusion equation. Within the semi classical theory of Sisyphus cooling we derive this fractional equation and discuss its meaning and its limitations [1,2]. An asymptotically weak friction force, induced by the laser field, is responsible for the large deviations from normal transport theory (and from Boltzmann-Gibbs equilibrium concepts [3]) at least below a critical value of the depth of the optical lattice. 1. E. Barkai, E. Aghion, and D. Kessler From the area under the Bessel excursion to anomalous diffusion of cold atoms Physical Review X 4, 021036 (2014) 2. D. A. Kessler, and E. Barkai Theory of fractional-Levy kinetics for cold atoms diffusing in optical lattices Phys. Rev. Lett. 108, 230602 (2012). 3. A. Dechant, D. A. Kessler and E. Barkai Deviations from Boltzmann-Gibbs equilibrium in confined optical lattices arXiv:1412.5402 [cond-mat.stat-mech] (2014). Room 301, Physics Bld. 202 המחלקה לפיזיקה physics.dept@mail.biu.ac.il Asia/Jerusalem public
Place
Room 301, Physics Bld. 202
Abstract

Fractional calculus is an old branch of mathematics which deals with fractional order derivatives. Recently the Davidson's group (Weizmann) has recorded the spatial diffusion of cold atoms in optical lattices, fitting the results to the solution of a fractional diffusion equation. Within the semi classical theory of Sisyphus cooling we derive this fractional equation and discuss its meaning and its limitations [1,2]. An asymptotically weak friction force, induced by the laser field, is responsible for the large deviations from normal transport theory (and from Boltzmann-Gibbs equilibrium concepts [3]) at least below a critical value of the depth of the optical lattice.

1. E. Barkai, E. Aghion, and D. Kessler From the area under the Bessel excursion to anomalous diffusion of cold atoms Physical Review X 4, 021036 (2014)
2. D. A. Kessler, and E. Barkai Theory of fractional-Levy kinetics for cold atoms diffusing in optical lattices Phys. Rev. Lett. 108, 230602 (2012).
3. A. Dechant, D. A. Kessler and E. Barkai Deviations from Boltzmann-Gibbs equilibrium in confined optical lattices arXiv:1412.5402 [cond-mat.stat-mech] (2014).

Attached file

תאריך עדכון אחרון : 04/01/2015