236 research outputs found
Spontaneous rotating vortex rings in a parametrically driven polariton fluid
We present the theoretical prediction of spontaneous rotating vortex rings in
a parametrically driven quantum fluid of polaritons -- coherent superpositions
of coupled quantum well excitons and microcavity photons. These rings arise not
only in the absence of any rotating drive, but also in the absence of a
trapping potential, in a model known to map quantitatively to experiments. We
begin by proposing a novel parametric pumping scheme for polaritons, with
circular symmetry and radial currents, and characterize the resulting
nonequilibrium condensate. We show that the system is unstable to spontaneous
breaking of circular symmetry via a modulational instability, following which a
vortex ring with large net angular momentum emerges, rotating in one of two
topologically distinct states. Such rings are robust and carry distinctive
experimental signatures, and so they could find applications in the new
generation of polaritonic devices.Comment: 6 pages, 4 figure
Dynamics of individual Brownian rods in a microchannel flow
We study the orientational dynamics of heavy silica microrods flowing through
a microfluidic channel. Comparing experiments and Brownian dynamics simulations
we identify different particle orbits, in particular in-plane tumbling
behavior, which cannot be explained by classical Jeffery theory, and we relate
this behavior to the rotational diffusion of the rods. By constructing the
full, three-dimensional, orientation distribution, we describe the rod
trajectories and quantify the persistence of Jeffery orbits using temporal
correlation functions of the Jeffery constant. We find that our colloidal rods
lose memory of their initial configuration in about a second, corresponding to
half a Jeffery period.Comment: 5 pages, 4 figure
Search for the Radiative Capture d+d->^4He+\gamma Reaction from the dd\mu Muonic Molecule State
A search for the muon catalyzed fusion reaction dd --> ^4He +\gamma in the
dd\mu muonic molecule was performed using the experimental \mu CF installation
TRITON and NaI(Tl) detectors for \gamma-quanta. The high pressure target filled
with deuterium at temperatures from 85 K to 800 K was exposed to the negative
muon beam of the JINR phasotron to detect \gamma-quanta with energy 23.8 MeV.
The first experimental estimation for the yield of the radiative deuteron
capture from the dd\mu state J=1 was obtained at the level n_{\gamma}\leq
2\times 10^{-5} per one fusion.Comment: 9 pages, 3 Postscript figures, submitted to Phys. At. Nuc
ASSESSMENT OF SURVIVAL OF ZYGOMATIC IMPLANTS AND ROOT DENTAL IMPLANTS
Currently, dental implantation has taken a leading position in the complex treatment of various dental diseases as the main and the most progressive method of restoring the quality of life of patients. Work is devoted to studying of implants survival at 29 patients of specialized unit of multi-speciality hospital. 68 zygomatic implants and 137 root dental implants were set up to these patients. Implants were set up to get stomatologic rehabilitation of patients with the acquired adentia of jaws. The comparative assessment of survival of zygomatic and dental implants was carried out, the period of observation was 36 months. The assessment of survival of root dental implants at all patients operated for the reporting period of time was carried also out
A Deeper Insight into (Lu,Y)AG:Pr Scintillator Crystals
Interior of Czochralski-grown (Lu,Y)AG:Pr crystals has been examined by means of
several techniques, such as X-Ray Photoelectron Spectroscopy, X-Ray Diffraction,
Time-of-Flight Secondary Ion Mass Spectrometry, and magnetic susceptibility measurements. Additionally, their luminescence has been monitored at various combinations of a double-beam (X-ray/IR) excitation
QCD-like Theories at Finite Baryon and Isospin Density
We use 2-color QCD as a model to study the effects of simultaneous presence
of chemical potentials for isospin charge, , and for baryon number,
. We determine the phase diagrams for 2 and 4 flavor theories using the
method of effective chiral Lagrangians at low densities and weak coupling
perturbation theory at high densities. We determine the values of various
condensates and densities as well as the spectrum of excitations as functions
of and . A similar analysis of QCD with quarks in the adjoint
representation is also presented. Our results can be of relevance for lattice
simulations of these theories. We predict a phase of inhomogeneous condensation
(Fulde-Ferrel-Larkin-Ovchinnikov phase) in the 2 colour 2 flavor theory, while
we do not expect it the 4 flavor case or in other realizations of QCD with a
positive measure.Comment: 17 pages, 14 figure
A deeper insight into (Lu,Y)AG : Pr scintillator crystals
Interior of Czochralski-grown (Lu,Y)AG:Pr crystals has been examined by means of
several techniques, such as X-Ray Photoelectron Spectroscopy, X-Ray Diffraction,
Time-of-Flight Secondary Ion Mass Spectrometry, and magnetic susceptibility measurements.
Additionally, their luminescence has been monitored at various combinations of a double-beam
(X-ray/IR) excitation
Goldstini
Supersymmetric phenomenology has been largely bound to the hypothesis that
supersymmetry breaking originates from a single source. In this paper, we relax
this underlying assumption and consider a multiplicity of sectors which
independently break supersymmetry, thus yielding a corresponding multiplicity
of goldstini. While one linear combination of goldstini is eaten via the
super-Higgs mechanism, the orthogonal combinations remain in the spectrum as
physical degrees of freedom. Interestingly, supergravity effects induce a
universal tree-level mass for the goldstini which is exactly twice the
gravitino mass. Since visible sector fields can couple dominantly to the
goldstini rather than the gravitino, this framework allows for substantial
departures from conventional supersymmetric phenomenology. In fact, this even
occurs when a conventional mediation scheme is augmented by additional
supersymmetry breaking sectors which are fully sequestered. We discuss a number
of striking collider signatures, including various novel decay modes for the
lightest observable-sector supersymmetric particle, gravitinoless
gauge-mediated spectra, and events with multiple displaced vertices. We also
describe goldstini cosmology and the possibility of goldstini dark matter.Comment: 14 pages, 7 figures; references adde
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