Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'488'730
Articles rated: 2609

29 March 2024
 
  » arxiv » cond-mat/0610767

 Article overview


Universality in nonadiabatic behaviour of classical actions in nonlinear models with separatrix crossings
A.P. Itin ; S. Watanabe ;
Date 27 Oct 2006
Subject Other
AbstractWe discuss dynamics of approximate adiabatic invariants in several nonlinear models being related to physics of Bose-Einstein condensates (BEC). We show that nonadiabatic dynamics in Feschbach resonance passage, nonlinear Landau-Zener (NLZ) tunnelling, and BEC tunnelling oscillations in a double-well can be considered within a unifying approach based on the theory of separatrix crossings. The problems were considered previously within nonlinear two-state models, and there are regimes of motion that was not discussed so far in the context of nonadiabatic behaviour, that is when initial populations of either mode of a two-mode system are not zero or very small. Here we consider a two-mode model for coupled atom-molecular BEC, and a two-mode model for two coupled (atomic) BECs as examples. The former model is able to describe process of Feschbach resonance passage, while the latter is similar to NLZ model. Self-trapping phenomenon and the associated emph{geometric} jump in action can lead to nonzero adiabatic tunnelling in NLZ models and non-zero remnant population at adiabatic Feschbach resonance crossing. However, the most complicated issue is emph{dynamical} jumps in action at separatrix crossings which were investigated previously in some problems of classical mechanics, plasma physics and hydrodynamics, but have not got adequate treatment in BEC-related models yet. We derive explicit formulas for the change in the action in several models using a general method of classical adiabatic theory. Extensive numerical calculations support the general theory and demonstrate its universal character. We also discovered a qualitatively new nonlinear phenomenon in a NLZ model which we propose to call {em separated adiabatic tunnelling}.
Source arXiv, cond-mat/0610767
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica