相关论文: Superluminality and Pair-Production
Gamma-ray bursts (GRBs) are believed to originate from ultra-relativistic winds/fireballs to avoid the "compactness problem". However, the most energetic photons in GRBs may still suffer from $\gamma-\gamma$ absorption leading to…
Recent cosmological observations indicate the existence of extra light species, i.e., dark radiation. In this paper we show that signatures of the dark radiation are imprinted in the spectrum of inflationary gravitational waves. If the dark…
Costache et al. have reported recently a new type of periodic patterns generated at femtosecond laser ablation of transparent dielectrics (Appl. Surf. Sci. 186, 352(2002)). They show features known from other pattern forming systems far…
We examine the phenomenon of electron-positron pair production from vacuum in a combination of two counterpropagating electromagnetic pulses having a duration of the order of the Compton time. We show that in this extreme short-time domain,…
The phenomenological implications of the eleven dimensional limit of $M$-theory (strongly coupled $E_8\times E_8$) are investigated. In particular we calculate the supersymmetric particle spectrum subject to constraints of correct…
Several binary systems consisting of a massive star and a compact object have been detected above 100 GeV in the Galaxy. In most of these sources, gamma-rays show a modulation associated to the orbital motion, which means that the emitter…
We estimate dark matter density for the Universe with a reheating temperature smaller than the mass of dark matter, assuming dark matter to be a weakly interacting massive particle. During the reheating process, an inflaton decays and…
We investigate the transient coherent transmission of light through an optically thick cold stron-tium gas. We observe a coherent superflash just after an abrupt probe extinction, with peak intensity more than three times the incident one.…
Spectral singularities appearing in parity-time (PT)-symmetric non-Hermitian optical systems have aroused a growing interest due to their new, exhilarating applications, such as bifurcation effects at exceptional points and the coexistence…
Quasar pairs are either physically distinct binary quasars or the result of gravitational lensing. The majority of known pairs are in fact lenses, with a few confirmed as binaries, leaving a population of objects that have not yet been…
Amplified spontaneous emission is a common noise source in active optical systems, it is generally seen as being an incoherent process. Here we excite an ensemble of rare earth ion dopants in a solid with a {\pi}-pulse, resulting in…
Transition radiation is a fundamental process of light emission and occurs whenever a charged particle moves across an inhomogeneous region. One feature of transition radiation is that it can create light emission at arbitrary frequency…
We show that the Coulomb barrier at the quark surface of a hot strange star may be a powerful source of $e^+e^-$ pairs which are created in an extremely strong electric field of the barrier and flow away from the star. The luminosity in the…
A semi-classical theory of coherent light scattering from an elongated sample of cold atoms exposed to an off-resonant laser beam is presented. The model, which is a direct extension of that of the collective atomic recoil laser (CARL),…
We study the gravitational production of super-Hubble-mass dark matter in the very early universe. We first review the simplest scenario where dark matter is produced mainly during slow roll inflation. Then we move on to consider the cases…
A phenomenological model is presented to explain the light curves of gamma-ray bursts. Gamma-rays are produced in a narrow beam which sweeps through space due to the precession of a slaved accretion disc. The light curve expected from such…
Stars are generally spherical, yet their gaseous envelopes often appear non-spherical when ejected near the end of their lives. This quirk is most notable during the planetary nebula phase when these envelopes become ionized. Interactions…
Radiation reaction is revisited, first in a new classical aproach, where the physical particle 4-momentum is redefined as the energy-momentum flux across the future light cone and is not parallel to the 4-velocity. Then in a semi-classical…
For many years it has been considered puzzling how pulsar radio emission, supposedly created by a circulating carousel of sub-beams, can produce the driftbands demonstrated by PSR J0815+09, and more recently PSR B1839-04, which…
Production of particle-antiparticle pairs by a high-energy probe photon propagating through a high-intensity laser field is considered in the nonperturbative interaction regime. The laser field consists of a strong low-frequency and a weak…