1,475 research outputs found
Finite temperature dynamical properties of SU() fermionic Hubbard models in the spin-incoherent regime
We study strongly correlated Hubbard systems extended to symmetric
-component fermions. We focus on the intermediate-temperature regime between
magnetic superexchange and interaction energy, which is relevant to current
ultracold fermionic atom experiments. The -component fermions are
represented by slave particles, and, by using a diagrammatic technique based on
the atomic limit, spectral functions are analytically obtained as a function of
temperature, filling factor and the component number . We also apply this
analytical technique to the calculation of lattice modulation experiments. We
compute the production rate of double occupancy induced by modulation of an
optical lattice potential. Furthermore, we extend the analysis to take into
account the trapping potential by use of the local density approximation. We
find an excellent agreement with recent experiments on Yb atoms.Comment: 15 pages, 13 figures, published versio
Unconventional superfluidity in quasi-one-dimensional systems
We show that an unconventional superfluid triggered by spin-orbit coupling is
realized for repulsively interacting quasi-one-dimensional fermions. A
competition between spin-singlet and -triplet pairings occurs due to the
breaking of inversion symmetry. We show that both superfluid correlations decay
algebraically with the same exponent except for special coupling constants for
which a dominant superfluid is controlled by the spin-orbit coupling. We also
discuss a possible experiment to observe such phases with cold atoms.Comment: 5 pages, 2 figure
Doublon production rate in modulated optical lattices
We study theoretically lattice modulation experiments with ultracold fermions
in optical lattices. We focus on the regime relevant to current experiments
when interaction strength is larger than the bandwidth and temperature is
higher than magnetic superexchange energy. We obtain analytical expressions for
the rate of doublon production as a function of modulation frequency, filling
factor, and temperature. We use local density approximation to average over
inhomogeneous density for atoms in a parabolic trap and find excellent
agreement with experimentally measured values. Our results suggest that lattice
modulation experiments can be used for thermometry of strongly interacting
fermionic ensembles in optical lattices.Comment: 7 pages, 6 figures, final versio
Spectroscopy for cold atom gases in periodically phase-modulated optical lattices
The response of cold atom gases to small periodic phase modulation of an
optical lattice is discussed. For bosonic gases, the energy absorption rate is
given, within linear response theory, by imaginary part of the current
correlation function. For fermionic gases in a strong lattice potential, the
same correlation function can be probed via the production rate double
occupancy. The phase modulation gives thus direct access to the conductivity of
the system, as function of the modulation frequency. We give an example of
application in the case of one dimensional bosons at zero temperature and
discuss the link between the phase- and amplitude-modulation.Comment: 4 pages, 2 figures, final versio
Dynamics of one-dimensional Bose liquids: Andreev-like reflection at Y-junctions and absence of the Aharonov-Bohm effect
We study one dimensional Bose liquids of interacting ultracold atoms in the
Y-shaped potential when each branch is filled with atoms. We find that the
excitation packet incident on a single Y-junction should experience a negative
density reflection analogous to the Andreev reflection at normal-superconductor
interfaces, although the present system does not contain fermions. In a ring
interferometer type configuration, we find that the transport is completely
insensitive to the (effective) flux contained in the ring, in contrast to the
Aharonov-Bohm effect of a single particle in the same geometry.Comment: 4 pages, 2 figures, final versio
Calibration of Photomultiplier Tubes for the Fluorescence Detector of Telescope Array Experiment using a Rayleigh Scattered Laser Beam
We performed photometric calibration of the PhotoMultiplier Tube (PMT) and
readout electronics used for the new fluorescence detectors of the Telescope
Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen
laser beam. The experimental setup, measurement procedure, and results of
calibration are described. The total systematic uncertainty of the calibration
is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the
transport of the calibrated PMTs from the laboratory to the TA experimental
site.Comment: 43 pages, 15 figure
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