4,723 research outputs found
Detection of QED vacuum nonlinearities in Maxwell's equations by the use of waveguides
We present a novel method for detecting nonlinearities, due to quantum
electrodynamics through photon-photon scattering, in Maxwell's equation. The
photon-photon scattering gives rise to self-interaction terms, which are
similar to the nonlinearities due to the polarisation in nonlinear optics.
These self-interaction terms vanish in the limit of parallel propagating waves,
but if instead of parallel propagating waves the modes generated in wavesguides
are used, there will be a non-zero total effect. Based on this idea, we
calculate the nonlinear excitation of new modes and estimate the strength of
this effect. Furthermore, we suggest a principal experimental setup.Comment: 4 pages, REVTeX3. To appear in Phys. Rev. Let
Extending the Higgs sector: an extra singlet
An extension of the Standard Model with an additional Higgs singlet is
analyzed. Bounds on singlet admixture in 125 GeV h boson from electroweak
radiative corrections and data on h production and decays are obtained.
Possibility of double h production enhancement at 14 TeV LHC due to heavy higgs
contribution is considered.Comment: 18 pages, 7 figures. v2: one equation added; references received
after the publication of v1 are adde
Charmed penguin versus BAU
Since the Standard Model most probably cannot explain the large value of CP
asymmetries recently observed in D-meson decays we propose the fourth
quark-lepton generation explanation of it. As a byproduct weakly mixed leptons
of the fourth generation make it possible to save the baryon number of the
Universe from erasure by sphalerons. An impact of the 4th generation on BBN is
briefly discussed.Comment: 13 pages, 3 figures, version to be published in JETP Letter
New Physics at 1 TeV?
If decays of a heavy particle S are responsible for the diphoton excess with
invariant mass 750 GeV observed at the 13 TeV LHC run, it can be easily
accomodated in the Standard Model. Two scenarios are considered: production in
gluon fusion through a loop of heavy isosinglet quark(s) and production in
photon fusion through a loop of heavy isosinglet leptons. In the second case
many heavy leptons are needed or/and they should have large electric charges in
order to reproduce experimental data on .Comment: 7 pages, 4 figures, 1 tabl
Communication Society and Security: Current Threats and Legal Maintenance
Over many centuries, human societies across the globe have established progressively closer contacts. Recently, the pace of globalization has dramatically increased. Unprecedented changes in communications, transportation, and computer technology have given the process new impetus and made the world more interdependent than ever. Information resources and structures have become a tool for achieving a strategic advantage. The authenticity, credibility, and an adequate reflection of information realities represent the key challenges for the communication society. Our research aims to analyze the possibilities of establishing a profound system for countering legalization of proceeds from crime (money laundering) and creating efficient barriers against cybercrimes, such as hacking of personal data. The sphere of security of online communication processes has become an objective element of our life, and it couldn’t be ignored, especially due to further development of securing biometric personal data mechanisms
Short wavelength electromagnetic propagation in magnetized quantum plasmas
The quantum electrodynamical (QED) short wavelength correction on plasma wave
propagation for a non-relativistic quantum plasma is investigated. A general
dispersion relation for a thermal multi-component quantum plasma is derived. It
is found that the classical dispersion relation for any wave mode can be
modified to include quantum and short wavelength QED effects by simple
substitutions of the thermal velocity and the plasma frequency. Furthermore,
the dispersion relation has been modified to include QED effects of strong
magnetic fields. It is found that strong magnetic fields together with the
short wavelength QED correction will induce dispersion both in vacuum and in
otherwise non-dispersive plasma modes. Applications to laboratory and
astrophysical systems are discussed.Comment: 13 pages, 2 figure
Band structure and broadband compensation of absorption by amplification in layered optical metamaterials
The frequency dependence of the gain required to compensate for absorption is determined for a layered structure consisting of alternating absorbing and amplifying layers. It is shown that the fulfillment of the same conditions is required for the existence of a band structure consisting of alternating bands allowed and forbidden for optical radiation propagation in the frequency-wave vector parametric region. Conditions are found under which the gain required for compensation is smaller than thresholds for absolute (parasitic lasing) and convective (waveguide amplification of radiation) instabilities
Numerical LES models of Richtmyer-Meshkov and Rayleigh-Taylor instabilities
Experimental and numerical results on the advance of a mixing or non-mixing front occurring at a density interface due to gravitational acceleration are analyzed considering the fractal and spectral structure of the front. The experimental configuration consists on a unstable two layer system held by a removable plate in a box for the Rayleigh-Taylor fronts and a dropping box on rails and shock tube high Mach number impulse across a density interface air/SF6.
The evolution of the turbulent mixing layer and its complex configuration is studied taking into account the dependence on the initial modes at the early stages and its spectral, self-similar information. Most models of the turbulent mixing evolution generated by hydrodynamics instabilities do not include any dependence on initial conditions, but in many relevant physical problems this dependence is very important, for instance, in Inertial Confinement Fussion target implosion. We discuss simple initial conditions with the aid of a numerical model developed at FIAN Lebedev which was compared with results of many simulations. The analysis of Kelvin-Helmholtz, Rayleigh-Taylor, Richtmyer-Meshkov and of accelerated instabilities is presented locally, and seen to dominate the turbulent cascade mixing zone differently under different initial conditions. Simulations and multifractal and neuron network analysis of Turbulent Mixing under RT and RM instabilities are presented for the different experiments and numerical simulations. In another paper in this proceedings volume further analysis on the numerical model is presented using wavelet preprocessing of the simulation results and neuron network presentation of the data with Kohonen map techniques (Stepanov et al.2004).Postprint (author’s final draft
Phosphate Biomineralization of Cambrian Microorganisms
As part of a long term study of biological markers (biomarkers), we are documenting a variety of features which reflect the previous presence of living organisms. As we study meteorites and samples returned from Mars, our main clue to recognizing possible microbial material may be the presence of biomarkers rather than the organisms themselves. One class of biomarkers consists of biominerals which have either been precipitated directly by microorganisms, or whose precipitation has been influenced by the organisms. Such microbe-mediated mineral formation may include important clues to the size, shape, and environment of the microorganisms. The process of fossilization or mineralization can cause major changes in morphologies and textures of the original organisms. The study of fossilized terrestrial organisms can help provide insight into the interpretation of mineral biomarkers. This paper describes the results of investigations of microfossils in Cambrian phosphate-rich rocks (phosphorites) that were found in Khubsugul, Northern Mongolia
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