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Title: Stability and tunneling dynamics of a dark-bright soliton pair in a harmonic trap

In this study, we consider a binary repulsive Bose-Einstein condensate in a harmonic trap in one spatial dimension and investigate particular solutions consisting of two dark-bright solitons. There are two different stationary solutions characterized by the phase difference in the bright component, in-phase and out-of-phase states. We show that above a critical particle number in the bright component, a symmetry-breaking bifurcation of the pitchfork type occurs that leads to a new asymmetric solution whereas the parental branch, i.e., the out-of-phase state, becomes unstable. These three different states support different small amplitude oscillations, characterized by an almost stationary density of the dark component and a tunneling of the bright component between the two dark solitons. Within a suitable effective double-well picture, these can be understood as the characteristic features of a bosonic Josephson junction (BJJ), and we show within a two-mode approach that all characteristic features of the BJJ phase space are recovered. For larger deviations from the stationary states, the simplifying double-well description breaks down due to the feedback of the bright component onto the dark one, causing the solitons to move. In this regime we observe intricate anharmonic and aperiodic dynamics, exhibiting remnants of the BJJ phase space.
Authors:
 [1] ;  [1] ;  [2] ;  [3]
  1. Univ. Hamburg, Hamburg (Germany)
  2. Univ. of Massachusetts, Amherst, MA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. Hamburg, Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Hamburg (Germany)
Publication Date:
OSTI Identifier:
1233190
Report Number(s):
LA--UR-14-28727
Journal ID: ISSN 1050-2947; PLRAAN; TRN: US1600427
Grant/Contract Number:
885/26-1; NSF-DMS-1312856; FA9550-12-1-0332; AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 91; Journal Issue: 4; Journal ID: ISSN 1050-2947
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 97 MATHEMATICS AND COMPUTING