3,008 research outputs found
Spin induced multipole moments for the gravitational wave amplitude from binary inspirals to 2.5 Post-Newtonian order
Using the NRGR effective field theory formalism we calculate the remaining
source multipole moments necessary to obtain the spin contributions to the
gravitational wave amplitude to 2.5 Post-Newtonian (PN) order. We also
reproduce the tail contribution to the waveform linear in spin at 2.5PN arising
from the nonlinear interaction between the current quadrupole and the mass
monopole.Comment: 17 pages, 4 figures. v2 Minor changes, to appear in JCA
Constraints on a scale-dependent bias from galaxy clustering
We forecast the future constraints on scale-dependent parametrizations of
galaxy bias and their impact on the estimate of cosmological parameters from
the power spectrum of galaxies measured in a spectroscopic redshift survey. For
the latter we assume a wide survey at relatively large redshifts, similar to
the planned Euclid survey, as baseline for future experiments. To assess the
impact of the bias we perform a Fisher matrix analysis and we adopt two
different parametrizations of scale-dependent bias. The fiducial models for
galaxy bias are calibrated using a mock catalogs of H emitting galaxies
mimicking the expected properties of the objects that will be targeted by the
Euclid survey.
In our analysis we have obtained two main results. First of all, allowing for
a scale-dependent bias does not significantly increase the errors on the other
cosmological parameters apart from the rms amplitude of density fluctuations,
, and the growth index , whose uncertainties increase by a
factor up to two, depending on the bias model adopted. Second, we find that the
accuracy in the linear bias parameter can be estimated to within 1-2\%
at various redshifts regardless of the fiducial model. The non-linear bias
parameters have significantly large errors that depend on the model adopted.
Despite of this, in the more realistic scenarios departures from the simple
linear bias prescription can be detected with a significance at
each redshift explored.
Finally, we use the Fisher Matrix formalism to assess the impact of assuming
an incorrect bias model and found that the systematic errors induced on the
cosmological parameters are similar or even larger than the statistical ones.Comment: new section added; conclusions unchanged; accepted for publication in
PR
Turismo e artigianato del \u201cfalso d\u2019autore\u201d per lo sviluppo locale del comune di Centuripe
Strongly inhibited transport of a 1D Bose gas in a lattice
We report the observation of strongly damped dipole oscillations of a quantum
degenerate 1D atomic Bose gas in a combined harmonic and optical lattice
potential. Damping is significant for very shallow axial lattices (0.25 photon
recoil energies), and increases dramatically with increasing lattice depth,
such that the gas becomes nearly immobile for times an order of magnitude
longer than the single-particle tunneling time. Surprisingly, we see no
broadening of the atomic quasimomentum distribution after damped motion. Recent
theoretical work suggests that quantum fluctuations can strongly damp dipole
oscillations of 1D atomic Bose gas, providing a possible explanation for our
observations.Comment: 5 pages, 4 figure
Recent advancements in the use of aerosol-assisted atmospheric pressure plasma deposition
Atmospheric pressure plasma allows for the easy modification of materials' surfaces for a wide range of technological applications. Coupling the aerosol injection of precursors with atmospheric pressure plasma largely extends the versatility of this kind of process; in fact solid and, in general, scarcely volatile precursors can be delivered to the plasma, extending the variety of chemical pathways to surface modification. This review provides an overview of the state of the art of aerosol-assisted atmospheric pressure plasma deposition. Advantages (many), and drawbacks (few) will be illustrated, as well as hints as to the correct coupling of the atomization source with the plasma to obtain specific coatings. In particular, the deposition of different organic, hybrid inorganic-organic and bioactive nanocomposite coatings will be discussed. Finally, it will be shown that, in particular cases, unique core-shell nanocapsules can be obtained
Principles and applications of a new class of soil water matric potential sensors: the dihedral tensiometer.
Accumulation and thermalization of cold atoms in a finite-depth magnetic trap
We experimentally and theoretically study the continuous accumulation of cold
atoms from a magneto-optical trap (MOT) into a finite depth trap, consisting in
a magnetic quadrupole trap dressed by a radiofrequency (RF) field. Chromium
atoms (52 isotope) in a MOT are continuously optically pumped by the MOT lasers
to metastable dark states. In presence of a RF field, the temperature of the
metastable atoms that remain magnetically trapped can be as low as 25 microK,
with a density of 10^17 atoms.m-3, resulting in an increase of the phase-space
density, still limited to 7.10^-6 by inelastic collisions. To investigate the
thermalization issues in the truncated trap, we measure the free evaporation
rate in the RF-truncated magnetic trap, and deduce the average elastic cross
section for atoms in the 5D4 metastable states, equal to 7.0 10^-16m2.Comment: 9 pages, 10 Figure
Sensor de água no solo por reflexão de luz em partículas de vidro com granulometria controlada.
- …