28,392 research outputs found
General Hubbard model for strongly interacting fermions in an optical lattice and its phase detection
Based on consideration of the system symmetry and its Hilbert space, we show
that strongly interacting fermions in an optical lattice or superlattice can be
generically described by a lattice resonance Hamiltonian. The latter can be
mapped to a general Hubbard model with particle assisted tunneling rates. We
investigate the model under population imbalance and show the attractive and
the repulsive models have the same complexity in phase diagram under the
particle-hole mapping. Using this mapping, we propose an experimental method to
detect possible exotic superfluid/magnetic phases for this system.Comment: 5 pages, 4 figure
Trapped ion quantum computation with transverse phonon modes
We propose a scheme to implement quantum gates on any pair of trapped ions
immersed in a large linear crystal, using interaction mediated by the
transverse phonon modes. Compared with the conventional approaches based on the
longitudinal phonon modes, this scheme is much less sensitive to ion heating
and thermal motion outside of the Lamb-Dicke limit thanks to the stronger
confinement in the transverse direction. The cost for such a gain is only a
moderate increase of the laser power to achieve the same gate speed. We also
show how to realize arbitrary-speed quantum gates with transverse phonon modes
based on simple shaping of the laser pulses.Comment: 5 page
States of fermionic atoms in an optical superlattice across a Feshbach resonance
We investigate states of fermionic atoms across a broad Feshbach resonance in
an optical superlattice which allows interaction only among a small number of
lattice sites. The states are in general described by superpositions of atomic
resonating valence bonds and dressed molecules. As one scans the magnetic
field, level crossing is found between states with different symmetry
properties, which may correspond to a quantum phase transition in the many-body
case.Comment: 10 pages, 11 figure
Test of Particle-Assisted Tunneling for Strongly Interacting Fermions in an Optical Superlattice
Fermions in an optical lattice near a wide Feshbach resonance are expected to
be described by an effective Hamiltonian of the general Hubbard model with
particle-assisted tunneling rates resulting from the strong atomic interaction
[Phys. Rev. Lett. 95, 243202 (2005)]. Here, we propose a scheme to
unambiguously test the predictions of this effective Hamiltonian through
manipulation of ultracold atoms in an inhomogeneous optical superlattice. The
structure of the low-energy Hilbert space as well as the particle assisted
tunneling rates can be inferred from measurements of the time-of-flight images.Comment: 4 pages, 4 figure
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