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Coherent backscattering of Bose-Einstein condensates in two-dimensional disorder potentials
Michael Hartung1, Thomas Wellens, Cord A Müller
1Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany.
Physical Review Letters
|September 4, 2008
Summary
Quantum transport in Bose-Einstein condensates shows a sharp scattering cone without interactions. Weak interactions turn this into a dip, revealing destructive interference in disordered potentials.
Area of Science:
- Quantum physics
- Condensed matter physics
- Atomic physics
Background:
- Bose-Einstein condensates (BECs) are quantum states of matter formed by cooling bosons to near absolute zero.
- Quantum transport describes how particles move through a medium under quantum mechanical rules.
- Disorder potentials introduce randomness, significantly affecting quantum phenomena like interference.
Purpose of the Study:
- To investigate quantum transport phenomena in interacting Bose-Einstein condensates within a 2D disorder potential.
- To understand the role of atom-atom interactions on coherent backscattering and interference patterns.
- To theoretically model the observed changes in scattering due to weak nonlinearity.
Main Methods:
- Numerical integration of the Gross-Pitaevskii equation to simulate condensate behavior.
- Development of a diagrammatic theory to analyze weak localization effects.
- Analysis of angle-resolved density of scattered matter waves to observe interference patterns.
Main Results:
- A sharp cone in the angle-resolved density was observed in the vanishing interaction limit, attributed to constructive interference.
- Weak atom-atom interactions transformed the constructive interference cone into a pronounced dip, indicating destructive interference.
- The diagrammatic theory successfully reproduced the numerical results, validating the model for nonlinear weak localization.
Conclusions:
- Atom-atom interactions fundamentally alter quantum interference in disordered Bose-Einstein condensates.
- The transition from constructive to destructive interference highlights the impact of nonlinearity on coherent backscattering.
- The study provides a theoretical framework for understanding quantum transport in interacting quantum systems.
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