772 research outputs found
Realization of Two-Dimensional Spin-orbit Coupling for Bose-Einstein Condensates
Cold atoms with laser-induced spin-orbit (SO) interactions provide intriguing
new platforms to explore novel quantum physics beyond natural conditions of
solids. Recent experiments demonstrated the one-dimensional (1D) SO coupling
for boson and fermion gases. However, realization of 2D SO interaction, a much
more important task, remains very challenging. Here we propose and
experimentally realize, for the first time, 2D SO coupling and topological band
with Rb degenerate gas through a minimal optical Raman lattice scheme,
without relying on phase locking or fine tuning of optical potentials. A
controllable crossover between 2D and 1D SO couplings is studied, and the SO
effects and nontrivial band topology are observed by measuring the atomic cloud
distribution and spin texture in the momentum space. Our realization of 2D SO
coupling with advantages of small heating and topological stability opens a
broad avenue in cold atoms to study exotic quantum phases, including the
highly-sought-after topological superfluid phases.Comment: 27 pages, 5 figure
Stability of Excited Dressed States with Spin-Orbit Coupling
We study the decay behaviors of ultracold atoms in metastable states with
spin-orbit coupling (SOC), and demonstrate that there are two SOC-induced decay
mechanisms. One arises from the trapping potential and the other is due to
interatomic collision. We present general schemes for calculating decay rates
from these two mechanisms, and illustrate how the decay rates can be controlled
by experimental parameters.We experimentally measure the decay rates over a
broad parameter region, and the results agree well with theoretical
calculations. This work provides an insight for both quantum simulation
involving metastable dressed states and studies on few-body problems with SO
coupling.Comment: 4.5 pages, 4 figures, the latest versio
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