Tunable spin-orbit-coupled Bose-Einstein condensates in deep optical lattices
Binary mixtures of Bose-Einstein condensates (BECs) trapped in deep optical lattices and subjected to equal contributions of Rashba and Dresselhaus spin-orbit coupling (SOC) are investigated in the presence of a periodic time modulation of the Zeeman field. SOC tunability is explicitly demonstrate...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
American Physical Society.
2016
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/52192/ http://irep.iium.edu.my/52192/ http://irep.iium.edu.my/52192/ http://irep.iium.edu.my/52192/1/2016-PhysRevA.94.043602.pdf http://irep.iium.edu.my/52192/7/52192_Tunable%20spin-orbit-coupled%20Bose-Einstein%20condensates%20in%20deep%20optical%20lattices_Scopus.pdf |
| Summary: | Binary mixtures of Bose-Einstein condensates (BECs) trapped in deep optical lattices and subjected to equal
contributions of Rashba and Dresselhaus spin-orbit coupling (SOC) are investigated in the presence of a periodic
time modulation of the Zeeman field. SOC tunability is explicitly demonstrated by adopting a mean-field
tight-binding model for the BEC mixture and by performing an averaging approach in the strong modulation
limit. In this case, the system can be reduced to an unmodulated vector discrete nonlinear Schr¨odinger equation
with a rescaled SOC tuning parameter α, which depends only on the ratio between amplitude and frequency
of the applied Zeeman field. We consider the attractive interaction case and focus on the effect of the SOC
tuning on the localized ground states. The dependence of the spectrum of the linear system on α has been
analytically characterized. In particular, we show that extremal curves (ground and highest excited states) of
the linear spectrum are continuous piecewise functions (together with their derivatives) of α, which consist of a
finite number of decreasing band lobes joined by constant lines. This structure also remains in the presence of
inter- and intra-species interactions, the nonlinearity mainly introducing a number of localized states in the band
gaps. The stability of ground states in the presence of the modulating field has been demonstrated by real-time
evolutions of the original (unaveraged) system. Localization properties of the ground state induced by the SOC
tuning, and a parameter design for possible experimental observation, have also been discussed. |
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