Non-equilibrium coherence dynamics in one-dimensional Bose gases

24. Sep 2007  — "Nature" reports that scientists at the TU Vienna and University Heidelberg successfully investigated the quantum dynamics in a one dimensional system in detail and even obtained a quantum mechanical state of equilibrium in it.


Non-equilibrium coherence dynamics in one-dimensional Bose gases


Watching (de) Coherence in an Interacting Many Body System:
Quantum coherence and Quantum noise is one of the most puzzling and fascinating aspects of quantum mechanics.  Coherence can be observed in interference experiments.

In many-body systems  it reveals the non-local correlations and entanglement of underlying many-body state.  In experiments reported by Hofferberth et al in the 20th September issue of  the journal Nature, the group at the Atominstitut Österreichischer Unversitäten presents experiments on AtomChips studying the  interference of  one dimensional systems, which reveal how the coherence slowly dies under the influence of an interacting many body system.  

For two isolated 1d Bose gases the coherence  factor  exhibit a universal sub-exponential coherence decay in perfect agreement with Luttinger Liquid theory. For coupled 1d Bose gases the coherence  factor is observed to approach a non-zero equilibrium value, the matter wave equivalent of phase locking two lasers by injection.

The non-equilibrium dynamics of superfluids studieb by Hofferberth et al. plays an important role in a wide range of physical systems, such as superconductors, quantum-Hall systems, superfluid Helium, and spin systems. These experiments studying coherence dynamics show that 1d Bose gases are ideally suited for investigating this class of phenomena.

Literature:

Hofferberth et al.
Non-equilibrium coherence dynamics in one-dimensional Bose gases
nature 449, 324 (2007).

News and Views: E. Altman, E. Demmler:
Relaxation after a tight squeeze
nature 449,  296 (2007)

Folman, R., Krüger, P., Schmiedmayer, J., Denschlag, J. & Henkel, C.
Microscopic atom optics: From wires to an atom chip.
Adv. At. Mol. Opt. Phys. 48, 263–356 (2002).