1,254 research outputs found
Fundamental length in quantum theories with PT-symmetric Hamiltonians
The direct observability of coordinates x is often lost in PT-symmetric
quantum theories. A manifestly non-local Hilbert-space metric enters
the double-integral normalization of wave functions there. In the
context of scattering, the (necessary) return to the asymptotically fully local
metric has been shown feasible, for certain family of PT-symmetric toy
Hamiltonians H at least, in paper I (M. Znojil, Phys. Rev. D 78 (2008) 025026).
Now we show that in a confined-motion dynamical regime the same toy model
proves also suitable for an explicit control of the measure or width
of its non-locality. For this purpose each H is assigned here, constructively,
the complete menu of its hermitizing metrics
distinguished by their optional "fundamental lengths" .
The local metric of paper I recurs at while the most popular
CPT-symmetric hermitization proves long-ranged, with .Comment: 31 pp, 3 figure
Gegenbauer-solvable quantum chain model
In an innovative inverse-problem construction the measured, experimental
energies , , ... of a quantum bound-state system are assumed
fitted by an N-plet of zeros of a classical orthogonal polynomial . We
reconstruct the underlying Hamiltonian (in the most elementary
nearest-neighbor-interaction form) and the underlying Hilbert space
of states (the rich menu of non-equivalent inner products is offered). The
Gegenbauer's ultraspherical polynomials are chosen for
the detailed illustration of technicalities.Comment: 29 pp., 1 fi
A New Template Family For The Detection Of Gravitational Waves From Comparable Mass Black Hole Binaries
In order to improve the phasing of the comparable-mass waveform as we
approach the last stable orbit for a system, various re-summation methods have
been used to improve the standard post-Newtonian waveforms. In this work we
present a new family of templates for the detection of gravitational waves from
the inspiral of two comparable-mass black hole binaries. These new adiabatic
templates are based on re-expressing the derivative of the binding energy and
the gravitational wave flux functions in terms of shifted Chebyshev
polynomials. The Chebyshev polynomials are a useful tool in numerical methods
as they display the fastest convergence of any of the orthogonal polynomials.
In this case they are also particularly useful as they eliminate one of the
features that plagues the post-Newtonian expansion. The Chebyshev binding
energy now has information at all post-Newtonian orders, compared to the
post-Newtonian templates which only have information at full integer orders. In
this work, we compare both the post-Newtonian and Chebyshev templates against a
fiducially exact waveform. This waveform is constructed from a hybrid method of
using the test-mass results combined with the mass dependent parts of the
post-Newtonian expansions for the binding energy and flux functions. Our
results show that the Chebyshev templates achieve extremely high fitting
factors at all PN orders and provide excellent parameter extraction. We also
show that this new template family has a faster Cauchy convergence, gives a
better prediction of the position of the Last Stable Orbit and in general
recovers higher Signal-to-Noise ratios than the post-Newtonian templates.Comment: Final published version. Accepted for publication in Phys. Rev.
Sphinx measurements of the 2009 solar minimum x-ray emission
The SphinX X-ray spectrophotometer on the CORONAS-PHOTON spacecraft measured
soft X-ray emission in the 1-15 keV energy range during the deep solar minimum
of 2009 with a sensitivity much greater than GOES. Several intervals are
identified when the X-ray flux was exceptionally low, and the flux and solar
X-ray luminosity are estimated. Spectral fits to the emission at these times
give temperatures of 1.7-1.9 MK and emission measures between 4 x 10^47 cm^-3
and 1.1 x 10^48 cm^-3. Comparing SphinX emission with that from the Hinode
X-ray Telescope, we deduce that most of the emission is from general coronal
structures rather than confined features like bright points. For one of 27
intervals of exceptionally low activity identified in the SphinX data, the
Sun's X-ray luminosity in an energy range roughly extrapolated to that of ROSAT
(0.1-2.4 keV) was less than most nearby K and M dwarfs.Comment: Astrophysical Journal, in press. 14 pp, 3 figure
Coronal loop hydrodynamics. The solar flare observedon November 12 1980 revisited: the UV line emission
We revisit a well-studied solar flare whose X-ray emission originating from a
simple loop structure was observed by most of the instruments on board SMM on
November 12 1980. The X-ray emission of this flare, as observed with the XRP,
was successfully modeled previously. Here we include a detailed modeling of the
transition region and we compare the hydrodynamic results with the UVSP
observations in two EUV lines, measured in areas smaller than the XRP rasters,
covering only some portions of the flaring loop (the top and the foot-points).
The single loop hydrodynamic model, which fits well the evolution of coronal
lines (those observed with the XRP and the \FeXXI 1354.1 \AA line observed with
the UVSP) fails to model the flux level and evolution of the \OV 1371.3 \AA
line.Comment: A&A, in press, 6 pages, 5 figure
Weak dipole moment of in collisions with longitudinally polarized electrons
It is pointed out that certain CP-odd momentum correlations in the production
and subsequent decay of tau pairs in collisions get enhanced when the
is longitudinally polarized. Analytic expressions for these correlations
are obtained for the single-pion decay mode of when have
a ``weak" dipole form factor (WDFF) coupling to . For collisions
at the peak, a sensitivity of about 1-5\mbox{ cm} for
the WDFF can be reached using a {\em single} decay
channel, with 's likely to be available at the SLC at Stanford with
polarization of 62\%-75\%.Comment: 9 pages, Latex, PRL-TH-93/17 (Revised
Newcastle Disease Virus Induces Profound Lymphoid Depletion with Different Patterns of Necroptosis, Necrosis, and Oxidative DNA Damage in Bursa, Spleen, and Other Lymphoid Tissues
This study delves into the pathogenesis of virulent genotype VII strains of the Newcastle disease virus (NDV), focusing on experimentally infected birds. Predominant and consistent lesions observed include bursal atrophy and extensive depletion of all lymphoid tissues. Immunohistochemistry (IHC) analysis, targeting apoptosis (Caspase-3), necroptosis (MLKL), and NDV markers, indicates that bursal atrophy is linked to a non-apoptotic programmed cell death pathway known as ânecroptosisâ. Repair assisted damage detection (RADD) of the bursa reveal oxidative DNA damage patterns consistent with programmed cell death, aligning with MLKL expression. Contrastingly, in the spleen, our findings suggest that necrosis (non-programmed cell death) predominantly contributes to lymphoid depletion. This conclusion is supported by evidence of karyorrhexis, fibrinous inflammation, RADD analyses, and IHC. Moreover, in addition to being pathogenic in its own right, NDV caused extensive and rapid lymphoid depletion that should be expected to contribute to profound immunosuppression. The elucidation of necroptosis in NDV-infected chickens provides a good rationale to investigate this mechanism in other paramyxoviral diseases such as human measles
Measurement of the electric dipole moment using longitudinal polarization of beams
Certain CP-odd momentum correlations in the production and subsequent decay
of pairs in collisions are enhanced significantly when the
and beams are longitudinally polarized. These may be used to probe
the real and imaginary parts of , the electric dipole moment of
the . Closed-form expressions for these ``vector correlations'' and the
standard deviation of the operators defining them due to standard model
interactions are presented for the two-body final states of decays. If
42\% average polarization of each beam is achieved, as proposed for the
tau-charm factories, with equal integrated luminosities for each sign of
polarization and a total yield of pairs, it is
possible to attain sensitivities for of , , cm respectively and for of , , cm respectively at the three operating center-of-mass energies of
3.67, 4.25 and 10.58 GeV. These bounds emerge when the effects of a posible
weak dipole form factor are negligible as is the case when it is of
the same order of magnitude as . Furthermore, in such a
polarization experiment where different polarizations are possible, a
model-independent disentangling of their individual effects is possible, and a
technique to achieve this is described. A strong longitudinal polarization
physics programme at the tau-charm factory appears warranted.Comment: 30 pages, latex, no figure
Self-Consistent MHD Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-Shaped Arcade Formation
We performed magnetohydrodynamic simulation of coronal mass ejections (CMEs)
and associated giant arcade formations, and the results suggested new
interpretations of observations of CMEs. We performed two cases of the
simulation: with and without heat conduction. Comparing between the results of
the two cases, we found that reconnection rate in the conductive case is a
little higher than that in the adiabatic case and the temperature of the loop
top is consistent with the theoretical value predicted by the Yokoyama-Shibata
scaling law. The dynamical properties such as velocity and magnetic fields are
similar in the two cases, whereas thermal properties such as temperature and
density are very different.In both cases, slow shocks associated with magnetic
reconnectionpropagate from the reconnection region along the magnetic field
lines around the flux rope, and the shock fronts form spiral patterns. Just
outside the slow shocks, the plasma density decreased a great deal. The soft
X-ray images synthesized from the numerical results are compared with the soft
X-ray images of a giant arcade observed with the Soft X-ray Telescope aboard
{\it Yohkoh}, it is confirmed that the effect of heat conduction is significant
for the detailed comparison between simulation and observation. The comparison
between synthesized and observed soft X-ray images provides new interpretations
of various features associated with CMEs and giant arcades.Comment: 39 pages, 18 figures. Accepted for publication in the Astrophysical
Journal. The PDF file with high resplution figures can be downloaded from
http://www.kwasan.kyoto-u.ac.jp/~shiota/study/ApJ62426.preprint.pdf
Director configuration of planar solitons in nematic liquid crystals
The director configuration of disclination lines in nematic liquid crystals
in the presence of an external magnetic field is evaluated. Our method is a
combination of a polynomial expansion for the director and of further
analytical approximations which are tested against a numerical shooting method.
The results are particularly simple when the elastic constants are equal, but
we discuss the general case of elastic anisotropy. The director field is
continuous everywhere apart from a straight line segment whose length depends
on the value of the magnetic field. This indicates the possibility of an
elongated defect core for disclination lines in nematics due to an external
magnetic field.Comment: 12 pages, Revtex, 8 postscript figure
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