2,139 research outputs found
Influence of the photon - neutrino processes on magnetar cooling
The photon-neutrino processes ,
and are investigated
in the presence of a strongly magnetized and dense electron-positron plasma.
The amplitudes of the reactions and
are obtained. In the case of a cold degenerate
plasma contributions of the considering processes to neutrino emissivity are
calculated. It is shown that contribution of the process to neutrino emissivity is supressed in comparision with the
contributions of the processes and
. The constraint on the magnetic field strength in the
magnetar outer crust is obtained.Comment: 8 pages, LaTeX, 2 PS figures, based on the talk presented by D.A.
Rumyantsev at the XV International Seminar Quarks'2008, Sergiev Posad, Moscow
Region, May 23-29, 2008, to appear in the Proceeding
Quantum coherence and interaction-free measurements
We investigate the extent to which ``interaction-free'' measurements perturb
the state of quantum systems. We show that the absence of energy exchange
during the measurement is not a sufficient criterion to preserve that state, as
the quantum system is subject to measurement dependent decoherence. While it is
possible in general to design interaction-free measurement schemes that do
preserve that state, the requirement of quantum coherence preservation rapidly
leads to a very low efficiency. Our results, which have a simple interpretation
in terms of ``which-way'' arguments, open up the way to novel quantum
non-demolition techniques.Comment: 4 pages incl. 2 PostScript figures (.eps), LaTeX using RevTeX,
submitted to Phys. Rev. A (Rapid Comm.
Copyright and Digital Sovereignty
Digital transformation affects all social spheres bringing to life interactive technologies and virtual reality. Since the virtual (digital) space depends on the digital and creative solutions that form its technological base, insofar the legal regime of copying creative solutions affects both the freedom of creativity necessary for sustainable development and public control which is significant for maintaining the manageability of sovereign states and integrational unions.Aim. Improving the legal regime for the protection of interactive works to create a universal and harmonious information space where the rights of authors and the economic interests of software developers are protected, as well as digital sovereignty is guaranteed.Tasks. The concept development for legal protection of interactive works and the political and legal modeling of the digital (information) space presuppose the implementation of international agreements in the field of intellectual rights, as well as solution of several tasks to formalize the results of the creative activity that are perceived through digital technologies.Methods. Political and legal modeling of the digital space is carried out by introducing terminological certainty and creating a system of the interactive works protection. Such legal construction should provide effective public control while preserving creative freedom in digital space.Results. The protection of the copyright and moral rights of the authors of interactive works differs significantly from the legal protection of audiovisual artworks and literature. While the form of objective expression in computer programs may be similar to a literary artwork, their perception by the target audience is fundamentally different in that it models a virtual (digital) space, which the state administration seeks to control in recent years.Conclusion. The state administration’s tendency to digital sovereignty makes sense only if the target audience demonstrates high demand for interactive artworks published under the state jurisdiction. Since the information space is universal, the digital sovereignty of the state is inextricably linked with participation in integration unions that ensure the p roper quality of the results of creative work and create the digital space that is necessary under digital transformation for the interactive art development and the prosperity of creative corporations
Results of a search for 2-decay of Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory
The experiment for the 2-decay of Xe search with two
high-pressure copper proportional counters has been held in Baksan neutrino
observatory. The search for the process is based on comparison of spectra
measured with natural and enriched xenon. No evidence has been found for
2(2)- and 2(0)-decay. The decay half lifetime limit
based on data measured during 8000 h is Tyr for
2-mode and Tyr for 0-mode (90%C.L.).Comment: 9 pages, 8 figures; talk at the NANP'05 Conference; submitted to
Phys. At. Nuc
Electrical and Noise Characteristics of Graphene Field-Effect Transistors: Ambient Effects and Noise Sources
We fabricated a large number of single and bilayer graphene transistors and
carried out a systematic experimental study of their low-frequency noise
characteristics. A special attention was given to determining the dominant
noise sources in these devices and the effect of aging on the current-voltage
and noise characteristics. The analysis of the noise spectral density
dependence on the area of graphene channel showed that the dominant
contributions to the low-frequency electronic noise come from the graphene
layer itself rather than from the contacts. Aging of graphene transistors due
to exposure to ambient for over a month resulted in substantially increased
noise attributed to the decreasing mobility of graphene and increasing contact
resistance. The noise spectral density in both single and bilayer graphene
transistors either increased with deviation from the charge neutrality point or
depended weakly on the gate bias. This observation confirms that the
low-frequency noise characteristics of graphene transistors are qualitatively
different from those of conventional silicon metal-oxide-semiconductor
field-effect transistors.Comment: 26 pages with 8 figure
SANC integrator in the progress: QCD and EW contributions
Modules and packages for the one-loop calculations at partonic level
represent the first level of SANC output computer product. The next level
represents Monte Carlo integrator mcsanc, realizing fully differential hadron
level calculations (convolution with PDF) for the HEP processes at LHC. In this
paper we describe the implementation into the framework mcsanc first set of
processes: DY NC, DY CC, ff->HW(Z) and single top production. Both EW and QCD
NLO corrections are taken into account. A comparison of SANC results with those
existing in the world literature is given
Nuclear deformation and the two neutrino double-\beta decay in ^{124,126}Xe,^{128,130}Te, ^{130,132}Ba and ^{150}Nd isotopes
The two neutrino double beta decay of Xe,Te, Ba and Nd isotopes is studied in the Projected
Hartree-Fock-Bogoliubov (PHFB) model. Theoretical 2
half-lives of Te, and Nd isotopes, and 2, 2 and 2 for Xe and Ba nuclei are presented. Calculated quadrupolar
transition probabilities B(E2: ), static quadrupole moments and
factors in the parent and daughter nuclei reproduce the experimental
information, validating the reliability of the model wave functions. The
anticorrelation between nuclear deformation and the nuclear transition matrix
element is confirmed.Comment: 19 page
Formation of "Lightnings" in a Neutron Star Magnetosphere and the Nature of RRATs
The connection between the radio emission from "lightnings" produced by the
absorption of high-energy photons from the cosmic gamma-ray background in a
neutron star magnetosphere and radio bursts from rotating radio transients
(RRATs) is investigated. The lightning length reaches 1000 km; the lightning
radius is 100 m and is comparable to the polar cap radius. If a closed
magnetosphere is filled with a dense plasma, then lightnings are efficiently
formed only in the region of open magnetic field lines. For the radio emission
from a separate lightning to be observed, the polar cap of the neutron star
must be directed toward the observer and, at the same time, the lightning must
be formed. The maximum burst rate is related to the time of the plasma outflow
from the polar cap region. The typical interval between two consecutive bursts
is ~100 s. The width of a single radio burst can be determined both by the
width of the emission cone formed by the lightning emitting regions at some
height above the neutron star surface and by a finite lightning lifetime. The
width of the phase distribution for radio bursts from RRATs, along with the
integrated pulse width, is determined by the width of the bundle of open
magnetic field lines at the formation height of the radio emission. The results
obtained are consistent with the currently available data and are indicative of
a close connection between RRATs, intermittent pulsars, and extreme nullers.Comment: 24 pages, no figures, references update
Two neutrino positron double beta decay of Cd for transition
The two neutrino positron double beta decay of Cd for 0
0 transition has been studied in the Hartree-Fock-Bogoliubov model in
conjunction with the summation method. In the first step, the reliability of
the intrinsic wave functions of Cd and Pd nuclei has been
tested by comparing the theoretically calculated results for yrast spectra,
reduced : transition probabilities, quadrupole moments
and gyromagnetic factors with the available experimental
data. In the second step, the nuclear transition matrix element and
the half-life for 0 0 transition have been
calculated with these wave functions. Moreover, we have studied the effect of
deformation on nuclear transition matrix element MComment: 20 page
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