373 research outputs found

    Electromagnetic shape resonances of a dielectric sphere and radiation of portable telephones

    Get PDF
    The frequency band used by cellular telephones includes the eigenfrequencies of a dielectric sphere with physical characteristics close to those of a human head. Proceeding from the spatial features of the natural modes of such a sphere we propose an independent and clear evident accuracy test for the complicated numerical calculations which are conducted when estimating the potential hazard due to the use of cellular telephones, in particular, for the check of a proper handling of the electromagnetic shape resonances of a human head.Comment: 10 pages, 1 figure with 2 eps file

    Neutrino mass spectrum from gravitational waves generated by double neutrino spin-flip in supernovae

    Full text link
    The supernova (SN) neutronization phase produces mainly electron (νe\nu_e) neutrinos, the oscillations of which must take place within a few mean-free-paths of their resonance surface located nearby their neutrinosphere. The state-of-the-art on the SN dynamics suggests that a significant part of these νe\nu_e can convert into right-handed neutrinos in virtue of the interaction of the electrons and the protons flowing with the SN outgoing plasma, whenever the Dirac neutrino magnetic moment be of strength μν<1011μB\mu_\nu < 10^{-11} \mu_{\rm B}, with μB\mu_{\rm B} being the Bohr magneton. In the supernova envelope, part of these neutrinos can flip back to the left-handed flavors due to the interaction of the neutrino magnetic moment with the magnetic field in the SN expanding plasma (Kuznetsov & Mikheev 2007; Kuznetsov, Mikheev & Okrugin 2008), a region where the field strength is currently accepted to be B1013B \gtrsim 10^{13} ~G. This type of ν\nu oscillations were shown to generate powerful gravitational wave (GW) bursts (Mosquera Cuesta 2000, Mosquera Cuesta 2002, Mosquera Cuesta & Fiuza 2004, Loveridge 2004). If such double spin-flip mechanism does run into action inside the SN core, then the release of both the oscillation-produced νμ\nu_\mus, ντ\nu_\taus and the GW pulse generated by the coherent ν\nu spin-flips provides a unique emission offset ΔTGWemissionν=0\Delta T^{emission}_{\rm GW} \leftrightarrow \nu = 0 for measuring the ν\nu travel time to Earth. As massive ν\nus get noticeably delayed on its journey to Earth with respect to the Einstein GW they generated during the reconversion transient, then the accurate measurement of this time-of-flight delay by SNEWS + LIGO, VIRGO, BBO, DECIGO, etc., might readily assess the absolute ν\nu mass spectrum.Comment: 14 pages, 2 figures, ApJ aastex.cls style. In press by The Astrophysical Journa

    Neutrino Oscillations Induced by Gravitational Recoil Effects

    Get PDF
    Quantum gravitational fluctuations of the space-time background, described by virtual D branes, may induce neutrino oscillations if a tiny violation of the Lorentz invariance (or a violation of the equivalence principle) is imposed. In this framework, the oscillation length of massless neutrinos turns out to be proportional to M/E^2, where E is the neutrino energy and M is the mass scale characterizing the topological fluctuations in the vacuum. Such a functional dependence on the energy is the same obtained in the framework of loop quantum gravity.Comment: 5 pages, LaTex fil

    Noninvasive electrocardiographic imaging of dynamic atrioventricular delay programming in a patient with left bundle branch block

    Get PDF
    Introduction The response to cardiac resynchronization therapy (CRT) is determined by various factors, including left ventricular (LV) lead location, atrioventricular (AV) delay, and inter-/intraventricular delays. Advances in quadripolar lead technology and device algorithms have improved patient response, yet selection of optimal settings remains challenging. Studies have shown acute improvement in electrical synchrony with manual AV optimization by fusion optimized intervals1,2; automated device algorithms, for example AdaptivCRT (Medtronic, Minneapolis, MN),3 SmartDelay (Boston Scientific, Marlborough, MA),4 and SyncAVTM (Abbott, Sylmar, CA)5; and pacing from multiple LV lead electrodes with MultiPoint Pacing (MPP).6,7 The aim of this clinical case report was to evaluate the acute benefits of SyncAV Plus in the new-generation, Bluetooth-enabled GallantTM CRT device (Abbott, Sylmar, CA). SyncAV Plus continually programs the paced AV delay shorter than the intrinsic PR interval by a programmable offset (% of PR duration) to synchronize intrinsic and ventricular paced activation wavefronts. Twelve-lead electrocardiogram (ECG) and noninvasive electrocardiographic imaging (ECGi) epicardial mapping analyses were performed to characterize the impact of SyncAV Plus on electrical synchrony during a range of CRT programming strategies, including biventricular (BiV) pacing, MPP, LV-only pacing, and LV-only pacing with MPP

    On the influence of the magnetic field of the GSI experimental storage ring on the time-modulation of the EC-decay rates of the H-like mother ions

    Full text link
    We investigate the influence of the magnetic field of the Experimental storage ring (ESR) at GSI on the periodic time-dependence of the orbital K-shell electron capture decay (EC(EC) rates of the H--like heavy ions. We approximate the magnetic field of the ESR by a uniform magnetic field. Unlike the assertion by Lambiase et al., arXiv: 0811.2302 [nucl-th], we show that a motion of the H-like heavy ion in a uniform magnetic field cannot be the origin of the periodic time-dependence of the EC-decay rates of the H-like heavy ions.Comment: 3 pages, 1 figur

    Effects of CPT and Lorentz Invariance Violation on Pulsar Kicks

    Full text link
    The breakdown of Lorentz's and CPT invariance, as described by the Extension of the Standard Model, gives rise to a modification of the dispersion relation of particles. Consequences of such a modification are reviewed in the framework of pulsar kicks induced by neutrino oscillations (active-sterile conversion). A peculiar feature of the modified energy-momentum relations is the occurrence of terms of the form \delta {\bbox \Pi}\cdot {\bf {\hat p}}, where \delta {\bbox \Pi} accounts for the difference of spatial components of flavor depending coefficients which lead to the departure of the Lorentz symmetry, and p^=p/p{\bf {\hat p}}={\bf p}/p, being p{\bf p} the neutrino momentum. Owing to the relative orientation of p{\bf p} with respect to \delta {\bbox \Pi}, the {\it coupling} \delta {\bbox \Pi}\cdot {\bf {\hat p}} may induce the mechanism to generate the observed pulsar velocities. Topics related to the velocity distribution of pulsars are also discussed.Comment: 10 pages, 1 figur

    Radiation in Lorentz violating electrodynamics

    Full text link
    Synchrotron radiation is analyzed in the classical effective Lorentz invariance violating model of Myers-Pospelov. Within the full far-field approximation we compute the electric and magnetic fields, the angular distribution of the power spectrum and the total emitted power in the m-th harmonic, as well as the polarization. We find the appearance of rather unexpected and large amplifying factors, which go together with the otherwise negligible naive expansion parameter. This opens up the possibility of further exploring Lorentz invariance violations by synchrotron radiation measurements in astrophysical sources where these amplifying factors are important.Comment: Presented at the Second Mexican Meeting on Theoretical and Experimental Physics, El Colegio Nacional, Mexico City, 6-10 September 200

    Spin-gravity coupling and gravity-induced quantum phases

    Full text link
    External gravitational fields induce phase factors in the wave functions of particles. The phases are exact to first order in the background gravitational field, are manifestly covariant and gauge invariant and provide a useful tool for the study of spin-gravity coupling and of the optics of particles in gravitational or inertial fields. We discuss the role that spin-gravity coupling plays in particular problems.Comment: 18 pages, 1 figur
    corecore