Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 57: Poster 3: Quantengase, Ultrakalte Atome, Ultrakalte Moleküle, Materiewellen Optik, Präzisionsmessungen, Metrologie
Q 57.1: Poster
Donnerstag, 17. März 2011, 16:30–19:30, P1
Weak Localisation with Short Loops — •Felix Eckert, Thomas Wellens, and Andreas Buchleitner — Physikalisches Institut, Albert-Ludwigs Universität, Freiburg, Germany
In multiply scattering weakly disordered media (i.e. the wavelength λ≪ mean free path ℓ), the average wave intensity is known to obey a diffusion equation. It is also well understood that interference effects lead to reduction of the diffusion, termed “weak localisation” and expressed by a decrease of the diffusion coefficient. These interference effects can be explained in terms of pairs of counterpropagating loops interfering constructively, thus enhancing the probability of return.
In the usual approach, these loops are calculated within the diffusion approximation, thus completely neglecting short loops, i.e. loops that consist of only a few scattering events. We present a calculation of the weak localisation corrections treating the propagation inside the loops exactly thus accounting also for the short loops. We find that the leading order correction to the diffusion coefficient scales linearly in λ/ℓ as opposed to the (λ/ℓ)2 predicted by the usual approach.