1,569 research outputs found
Stabilization of the p-wave superfluid state in an optical lattice
It is hard to stabilize the p-wave superfluid state of cold atomic gas in
free space due to inelastic collisional losses. We consider the p-wave Feshbach
resonance in an optical lattice, and show that it is possible to have a stable
p-wave superfluid state where the multi-atom collisional loss is suppressed
through the quantum Zeno effect. We derive the effective Hamiltonian for this
system, and calculate its phase diagram in a one-dimensional optical lattice.
The results show rich phase transitions between the p-wave superfluid state and
different types of insulator states induced either by interaction or by
dissipation.Comment: 5 pages, 5 figure
Quantum Field Theory for the Three-Body Constrained Lattice Bose Gas -- Part I: Formal Developments
We develop a quantum field theoretical framework to analytically study the
three-body constrained Bose-Hubbard model beyond mean field and non-interacting
spin wave approximations. It is based on an exact mapping of the constrained
model to a theory with two coupled bosonic degrees of freedom with polynomial
interactions, which have a natural interpretation as single particles and
two-particle states. The procedure can be seen as a proper quantization of the
Gutzwiller mean field theory. The theory is conveniently evaluated in the
framework of the quantum effective action, for which the usual symmetry
principles are now supplemented with a ``constraint principle'' operative on
short distances. We test the theory via investigation of scattering properties
of few particles in the limit of vanishing density, and we address the
complementary problem in the limit of maximum filling, where the low lying
excitations are holes and di-holes on top of the constraint induced insulator.
This is the first of a sequence of two papers. The application of the formalism
to the many-body problem, which can be realized with atoms in optical lattices
with strong three-body loss, is performed in a related work [14].Comment: 21 pages, 5 figure
Practitioner review: pathways to care for ADHD - a systematic review of barriers and facilitators
Background. Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder starting in childhood that may persist into adulthood. It can be managed through carefully monitored medication and nonpharmacological interventions. Access to care for children at risk of ADHD varies both within and between countries. A systematic literature review was conducted to investigate the research evidence related to factors which influence children accessing services for ADHD
State-dependent, addressable subwavelength lattices with cold atoms
We discuss how adiabatic potentials can be used to create addressable
lattices on a subwavelength scale, which can be used as a tool for local
operations and readout within a lattice substructure, while taking advantage of
the faster timescales and higher energy and temperature scales determined by
the shorter lattice spacing. For alkaline-earth-like atoms with non-zero
nuclear spin, these potentials can be made state dependent, for which we give
specific examples with Yb atoms. We discuss in detail the limitations
in generating the lattice potentials, in particular non-adiabatic losses, and
show that the loss rates can always be made exponentially small by increasing
the laser power.Comment: replaced with the published version. 23 pages, 11 figure
Large Area Crop Inventory Experiment (LACIE). Intensive test site assessment report
There are no author-identified significant results in this report
Optimal time-dependent lattice models for nonequilibrium dynamics
Lattice models are abundant in theoretical and condensed-matter physics.
Generally, lattice models contain time-independent hopping and interaction
parameters that are derived from the Wannier functions of the noninteracting
problem. Here, we present a new concept based on time-dependent Wannier
functions and the variational principle that leads to optimal time-dependent
lattice models. As an application, we use the Bose-Hubbard model with
time-dependent Wannier functions to study a quench scenario involving higher
bands. We find a separation of times scales in the dynamics and show that under
some circumstances the multi-band nonequilibrium dynamics of a quantum system
can be obtained essentially at the cost of a single-band model.Comment: 14 pages, 3 figure
Two-point correlation properties of stochastic "cloud processes''
We study how the two-point density correlation properties of a point particle
distribution are modified when each particle is divided, by a stochastic
process, into an equal number of identical "daughter" particles. We consider
generically that there may be non-trivial correlations in the displacement
fields describing the positions of the different daughters of the same "mother"
particle, and then treat separately the cases in which there are, or are not,
correlations also between the displacements of daughters belonging to different
mothers. For both cases exact formulae are derived relating the structure
factor (power spectrum) of the daughter distribution to that of the mother.
These results can be considered as a generalization of the analogous equations
obtained in ref. [1] (cond-mat/0409594) for the case of stochastic displacement
fields applied to particle distributions. An application of the present results
is that they give explicit algorithms for generating, starting from regular
lattice arrays, stochastic particle distributions with an arbitrarily high
degree of large-scale uniformity.Comment: 14 pages, 3 figure
Atomic lattice excitons: from condensates to crystals
We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed
by fermionic atoms in two bands of an optical lattice. Such a system provides a
clean setup to study fundamental properties of excitons, ranging from
condensation to exciton crystals (which appear for a large effective mass ratio
between particles and holes). Using both mean-field treatments and 1D numerical
computation, we discuss the properities of ALEs under varying conditions, and
discuss in particular their preparation and measurement.Comment: 19 pages, 15 figures, changed formatting for journal submission,
corrected minor errors in reference list and tex
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