M.Sc Thesis | |

M.Sc Student | Kushnir Maria |
---|---|

Subject | Transport and Weak Localization of Spin S Particles: Application to the Atom-Photon System |

Department | Department of Physics |

Supervisor | PROF. Eric Akkermans |

This thesis
deals with an investigation of the weak localization of spin *S*
particles. The weak localization corrections have been calculated and
experimentally observed in the case of electrons. Weak localization corrections
to the conductivity Δσ* *have been predicted and measured for spin
1/2 problem, giving rise to anti-localization regime. It is the main aim of
this thesis to extend the present status by describing weak localization of
spin 1 particles. We analyze the problem by presenting a new technique able to
evaluate weak localization of spin *S* particles - we introduce Hikami box
in the presence of particles with arbitrary spin. Applying that technique to
the spin 1/2 problem we calculate the weak localization correction to the
diffusion coefficient Δ*D*, and we recover the Einstein relation Δσ*
= se ^{2}ρ*Δ

Another case of interest is the multiple scattering of light by atoms with internal structure. For that problem, using the former technique, we find the averaged transmission coefficient and the weak localization correction to it as a function of polarization. In addition we obtain weak localization correction to the diffusion coefficient both for classical and degenerate atoms. Those results lead to three interesting conclusions: a) For the classical scatterers there is a possibility for weak localization. b) The internal degrees of freedom destroy this effect, so that there is no localization. c) There is no anti-localization for the light.