Condensed Matter Physics Seminar

2 p.m., Thursday, Spetember 19, 2002
Room 1201, Physics Building

 Controlled Tunneling of Cold Atoms:
from Full Suppression to Strong Enhancement

Nimrod Moiseyev

(Department of Chemistry and Minerva Center for Non-linear Physics of Complex Systems, Technion, Haifa, Israel)

Abstract:  In the talk we will show how the periodically driven rotor Hamiltonian which is a common model for classical and quantum chaos is associated with the recent pioneering experiments of Phillips and Raizen and their groups. In these experiments they have observed tunneling in phase space of cold atoms interacting with standing electromagnetic waves.

Using the Floquet-Bloch formalism we will briefly describe the generation of one dimensional optical lattice and the forces which provide the driving. We will show that two different mechanisms are responsible for the oscillations observed in these two experiments. These mechanisms are relevant to other physical phenomena. For example, they are relevant also for the enhancement or suppression of the transmission of electrons from one quantum well to another in solid state devices and the transfer of light from one wave guide to another in optical switches.

As we will show, one can achieve a control of the tunneling period over a range of several orders of magnitude by changing the frequency difference of the standing waves in the cold atom experiments by about 10% only.

Host:  Richard Prange
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