55,773 research outputs found
Quasiparticle Berry curvature and Chern numbers in spin-orbit coupled bosonic Mott insulators
We study the ground-state topology and quasiparticle properties in bosonic
Mott insulators with two- dimensional spin-orbit couplings in cold atomic
optical lattices. We show that the many-body Chern and spin-Chern number can be
expressed as an integral of the quasihole Berry curvatures over the Brillouin
zone. Using a strong-coupling perturbation theory, for an experimentally
feasible spin-orbit coupling, we compute the Berry curvature and the spin Chern
number and find that these quantities can be generated purely by interactions.
We also compute the quasiparticle dispersions, spectral weights, and the
quasimomentum space distribution of particle and spin density, which can be
accessed in cold-atom experiments and used to deduce the Berry curvature and
Chern numbers
Electronic visualization of gas bearing behavior
Visualization technique produces a visual simulation of gas bearing operation by electronically combining the outputs from the clearance probes used to monitor bearing component motion. Computerized recordings of the probes output are processed, displayed on an oscilloscope screen and recorded with a high-speed motion picture camera
Synthesising and utilising complex evidence to inform policy in education and health.
Oslo, Norway, May 19 to 21, 200
AERODYNAMIC CHARACTERISTICS OF TWO RECTANGULAR-PLAN-FORM, ALLMOVABLE CONTROLS IN COMBINATION WITH A SLENDER BODY OF REVOLUTION AT MACH NUMBERS FROM 3.00 TO 6.25
Aerodynamic characteristics of rectangular planform, all-movable controls combined with slender body of revolution at mach 3 to 6.2
Spin-Seebeck effect in a strongly interacting Fermi gas
We study the spin-Seebeck effect in a strongly interacting, two-component
Fermi gas and propose an experiment to measure this effect by relatively
displacing spin up and spin down atomic clouds in a trap using spin-dependent
temperature gradients. We compute the spin-Seebeck coefficient and related
spin-heat transport coefficients as functions of temperature and interaction
strength. We find that when the inter-spin scattering length becomes larger
than the Fermi wavelength, the spin-Seebeck coefficient changes sign as a
function of temperature, and hence so does the direction of the
spin-separation. We compute this zero-crossing temperature as a function of
interaction strength and in particular in the unitary limit for the inter-spin
scattering
Spin-transfer mechanism for magnon-drag thermopower
We point out a relation between the dissipative spin-transfer-torque
parameter and the contribution of magnon drag to the thermoelectric
power in conducting ferromagnets. Using this result we estimate in iron
at low temperatures, where magnon drag is believed to be the dominant
contribution to the thermopower. Our results may be used to determine
from magnon-drag-thermopower experiments, or, conversely, to infer the strength
of magnon drag via experiments on spin transfer
Elliptic Flow from a Transversally Thermalized Fireball
The agreement of elliptic flow data at RHIC at central rapidity with the
hydrodynamic model has led to the conclusion of very rapid thermalization. This
conclusion is based on the intuitive argument that hydrodynamics, which assumes
instantaneous local thermalization, produces the largest possible elliptic flow
values and that the data seem to saturate this limit. We here investigate the
question whether incompletely thermalized viscous systems may actually produce
more elliptic flow than ideal hydrodynamics. Motivated by the extremely fast
primordial longitudinal expansion of the reaction zone, we investigate a toy
model which exhibits thermalization only in the transverse directions but
undergoes collisionless free-streaming expansion in the longitudinal direction.
For collisions at RHIC energies, elliptic flow results from the model are
compared with those from hydrodynamics. With the final particle yield and
\kt-distribution fixed, the transversally thermalized model is shown not to
be able to produce the measured amount of elliptic flow. This investigation
provides further support for very rapid local kinetic equilibration at RHIC. It
also yields interesting novel results for the elliptic flow of massless
particles such as direct photons.Comment: revtex4, 15 pages + 10 embedded EPS figure
Effect of a standardised dietary restriction protocol on multiple laboratory strains of Drosophila melanogaster
Background:
Outcomes of lifespan studies in model organisms are particularly susceptible to variations in technical procedures. This is especially true of dietary restriction, which is implemented in many different ways among laboratories.
Principal Findings:
In this study, we have examined the effect of laboratory stock maintenance, genotype differences and microbial infection on the ability of dietary restriction (DR) to extend life in the fruit fly Drosophila melanogaster. None of these factors block the DR effect.
Conclusions:
These data lend support to the idea that nutrient restriction genuinely extends lifespan in flies, and that any mechanistic discoveries made with this model are of potential relevance to the determinants of lifespan in other organisms
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