34,110 research outputs found
Streaks to Rings to Vortex Grids: Generic Patterns in Transient Convective Spin-Up
We observe the transient formation of a ringed pattern state during spin-up
of an evaporating fluid on a time scale of order a few Ekman spin-up times. The
ringed state is probed using infrared thermometry and particle image
velocimetry and it is demonstrated to be a consequence of the transient balance
between Coriolis and viscous forces which dominate inertia, each of which are
extracted from the measured velocity field. The breakdown of the ringed state
is quantified in terms of the antiphasing of these force components which
drives a Kelvin-Helmholtz instability and we show that the resulting vortex
grid spacing scales with the ring wavelength. This is the fundamental route to
quasi-two dimensional turbulent vortex flow and thus may have implications in
astrophysics and geophysics wherein rotating convection is ubiquitous. sics.Comment: 4 pages, 5 figure
Study of interacting electrons in graphene under the renormalized-ring-diagram approximation
Using the tight-binding model with long-range Coulomb interactions between
electrons, we study some of the electronic properties of graphene. The Coulomb
interactions are treated with the renormalized-ring-diagram approximation. By
self-consistently solving the integral equations for the Green function, we
calculate the spectral density. The obtained result is in agreement with
experimental observation. In addition, we also compute the density of states,
the distribution functions, and the ground-state energy. Within the present
approximation, we find that the imaginary part of the self-energy fixed at the
Fermi momentum varies as quadratic in energy close to the chemical potential,
regardless the system is doped or not. This result appears to indicate that the
electrons in graphene always behave like a moderately correlated Fermi liquid.Comment: 11 pages, 13 figure
Electronic structure induced reconstruction and magnetic ordering at the LaAlOSrTiO interface
Using local density approximation (LDA) calculations we predict
GdFeO-like rotation of TiO octahedra at the -type interface between
LaAlO and SrTiO. The narrowing of the Ti bandwidth which results
means that for very modest values of , LDA calculations predict charge
and spin ordering at the interface. Recent experimental evidence for magnetic
interface ordering may be understood in terms of the close proximity of an
antiferromagnetic insulating ground state to a ferromagnetic metallic excited
state
Beam energy dependence of Hanbury-Brown-Twiss radii from a blast-wave model
The beam energy dependence of correlation lengths (the Hanbury-Brown-Twiss
radii) is calculated by using a blast-wave model and the results are comparable
with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE
measurements. A set of parameter for the blast-wave model as a function of beam
energy under study are obtained by fit to the HBT radii at each energy point.
The transverse momentum dependence of HBT radii is presented with the extracted
parameters for Au + Au collision at 200 GeV and for Pb+Pb
collisions at 2.76 TeV. From our study one can learn that particle emission
duration can not be ignored while calculating the HBT radii with the same
parameters. And tuning kinetic freeze-out temperature in a range will result in
system lifetime changing in the reverse direction as it is found in RHIC-STAR
experiment measurements.Comment: 9 pages, 9 figure
Flavor Evolution of the Neutronization Neutrino Burst from an O-Ne-Mg Core-Collapse Supernova
We present results of 3-neutrino flavor evolution simulations for the
neutronization burst from an O-Ne-Mg core-collapse supernova. We find that
nonlinear neutrino self-coupling engineers a single spectral feature of
stepwise conversion in the inverted neutrino mass hierarchy case and in the
normal mass hierarchy case, a superposition of two such features corresponding
to the vacuum neutrino mass-squared differences associated with solar and
atmospheric neutrino oscillations. These neutrino spectral features offer a
unique potential probe of the conditions in the supernova environment and may
allow us to distinguish between O-Ne-Mg and Fe core-collapse supernovae.Comment: 4 pages, 2 figures. Version accepted by PR
Interactions in Quasicrystals
Although the effects of interactions in solid state systems still remains a
widely open subject, some limiting cases such as the three dimensional Fermi
liquid or the one-dimensional Luttinger liquid are by now well understood when
one is dealing with interacting electrons in {\it periodic} crystalline
structures. This problem is much more fascinating when periodicity is lacking
as it is the case in {\it quasicrystalline} structures. Here, we discuss the
influence of the interactions in quasicrystals and show, on a controlled
one-dimensional model, that they lead to anomalous transport properties,
intermediate between those of an interacting electron gas in a periodic and in
a disordered potential.Comment: Proceedings of the Many Body X conference (Seattle, Sept. 99); 9
pages; uses epsfi
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