88 research outputs found
Thermodynamic Properties of Rashba Spin-Orbit-Coupled Fermi Gas
We investigate the thermodynamic properties of a superfluid Fermi gas subject
to Rashba spin-orbit coupling and effective Zeeman field. We adopt a T-matrix
scheme that takes beyond-mean-field effects, which are important for strongly
interacting systems, into account. We focus on the calculation of two important
quantities: the superfluid transition temperature and the isothermal
compressibility. Our calculation shows very distinct influences of the
out-of-plane and the in-plane Zeeman fields on the Fermi gas. We also confirm
that the in-plane Zeeman field induces a Fulde-Ferrell superfluid below the
critical temperature and an exotic finite-momentum pseudo-gap phase above the
critical temperature.Comment: 8 pages, 9 figure
Effective p-wave interaction and topological superfluids in s-wave quantum gases
P-wave interaction in cold atoms may give rise to exotic topological
superfluids. However, the realization of p-wave interaction in cold atom system
is experimentally challenging. Here we propose a simple scheme to synthesize
effective -wave interaction in conventional -wave interacting quantum
gases. The key idea is to load atoms into spin-dependent optical lattice
potential. Using two concrete examples involving spin-1/2 fermions, we show how
the original system can be mapped into a model describing spinless fermions
with nearest neighbor p-wave interaction, whose ground state can be a
topological superfluid that supports Majorana fermions under proper conditions.
Our proposal has the advantage that it does not require spin-orbit coupling or
loading atoms onto higher orbitals, which is the key in earlier proposals to
synthesize effective -wave interaction in -wave quantum gases, and may
provide a completely new route for realizing -wave topological superfluids.Comment: 5 pages, 4 figure
Bichromatic field generation from double-four-wave mixing in a double-electromagnetically induced transparency system
We demonstrate the double electromagnetically induced transparency
(double-EIT) and double four-wave mixing (double-FWM) based on a new scheme of
non-degenerate four-wave mixing (FWM) involving five levels of a cold 85Rb
atomic ensemble, in which the double-EIT windows are used to transmit the probe
field and enhance the third-order nonlinear susceptibility. The phase-matching
conditions for both four-wave mixings could be satisfied simultaneously. The
frequency of one component of the generated bichromatic field is less than the
other by the ground-state hyperfine splitting (3GHz). This specially designed
experimental scheme for simultaneously generating different nonlinear
wave-mixing processes is expected to find applications in quantum information
processing and cross phase modulation. Our results agree well with the
theoretical simulation.Comment: Accepted by NJ
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