General Relativistic Magnetospheres of Slowly Rotating and Oscillating Magnetized Neutron Stars

We study the magnetosphere of a slowly rotating magnetized neutron star subject to toroidal oscillations in the relativistic regime. Under the assumption of a zero inclination angle between the magnetic moment and the angular momentum of the star, we analyze the Goldreich-Julian charge density and derive a second-order differential equation for the electrostatic potential. The analytical solution of this equation in the polar cap region of the magnetosphere shows the modification induced by stellar toroidal oscillations on the accelerating electric field and on the charge density. We also find that, after decomposing the oscillation velocity in terms of spherical harmonics, the first few modes with $m=0,1$ are responsible for energy losses that are almost linearly dependent on the amplitude of the oscillation and that, for the mode $(l,m)=(2,1)$, can be a factor $\sim8$ larger than the rotational energy losses, even for a velocity oscillation amplitude at the star surface as small as $\eta=0.05 \ \Omega \ R$. The results obtained in this paper clarify the extent to which stellar oscillations are reflected in the time variation of the physical properties at the surface of the rotating neutron star, mainly by showing the existence of a relation between $P\dot{P}$ and the oscillation amplitude. Finally, we propose a qualitative model for the explanation of the phenomenology of intermittent pulsars in terms of stellar oscillations that are periodically excited by star glitches.Comment: 13 pages, 4 figures, submitted to MNRA

Explaining the subpulse drift velocity of pulsar magnetosphere within the space-charge limited flow model

We try to explain the subpulse drift phenomena adopting the space-charge limited flow (SCLF) model and comparing the plasma drift velocity in the inner region of pulsar magnetospheres with the observed velocity of drifting subpulses. We apply the approach described in a recent paper of van Leeuwen & Timokhin (2012), where it was shown that the standard estimation of the subpulse drift velocity through the total value of the scalar potential drop in the inner gap gives inaccurate results, while the exact expression relating the drift velocity to the gradient of the scalar potential should be used instead. After considering a selected sample of sources taken from the catalog of Weltevrede, Edwards & Stappers (2006) with coherently drifting subpulses and reasonably known observing geometry, we show that their subpulse drift velocities would correspond to the drift of the plasma located very close or above the pair formation front. Moreover, a detailed analysis of PSR B0826-34 and PSR B0818-41 reveals that the variation of the subpulse separation with the pulse longitude can be successfully explained by the dependence of the plasma drift velocity on the angular coordinates.Comment: 14 pages, 6 figures, 2 table

Quantum Interference Effects in Slowly Rotating NUT Space-time

General relativistic quantum interference effects in the slowly rotating NUT space-time as the Sagnac effect and the phase shift effect of interfering particle in neutron interferometer are considered. It was found that in the case of the Sagnac effect the influence of NUT parameter is becoming important due to the fact that the angular velocity of the locally non rotating observer must be larger than one in the Kerr space-time. In the case of neutron interferometry it is found that due to the presence of NUT-parameter an additional term in the phase shift of interfering particle emerges. This term can be, in principle, detected by sensitive interferometer and derived results can be further used in experiments to detect the gravitomagnetic charge. Finally, as an example, we apply the obtained results to the calculation of the UCN (ultra-cold neutrons) energy level modification in the slowly rotating NUT space-time.Comment: 11 pages, 1 figure, accepted for publication in Int. J. Mod. Phys. D; added reference

Nonsingular electrodynamics of a rotating black hole moving in an asymptotically uniform magnetic test field

We extend the Wald solution to a black hole that is also moving at constant velocity. More specifically, we derive analytic solutions for the Maxwell equations for a rotating black hole moving at constant speed in an asymptotically uniform magnetic test field. By adopting Kerr-Schild coordinates we avoid singular behaviors at the horizon and obtain a complete description of the charge and current distributions in terms of the black-hole spin and velocity. Using this solution, we compute the energy losses expected when charged particles are accelerated along the magnetic field lines, improving previous estimates that had to cope with singular electromagnetic fields on the horizon. When used to approximate the emission from binary black holes in a uniform magnetic field, our estimates match reasonably well those from numerical-relativity calculations in the force-free approximation

General Relativistic Effect of Gravitomagnetic Charge on Pulsar Magnetosphere and Particle Acceleration in a Polar Cap

We study magnetospheric structure surrounding rotating magnetized neutron star with nonvanishing NUT (Newman-Tamburino-Unti) parameter. For the simplicity of calculations Goldreich-Julian charge density is analyzed for the aligned neutron star with zero inclination between magnetic field, gravitomagnetic field and rotation axis. From the system of Maxwell equations in spacetime of slowly rotating NUT star, second-order differential equation for electrostatic potential is derived. Analytical solution of this equation indicates the general relativistic modification of an accelerating electric field and charge density along the open field lines by the gravitomagnetic charge. The implication of this effect to the magnetospheric energy loss problem is underlined. In the second part of the paper we derive the equations of motion of test particles in magnetosphere of slowly rotating NUT star. Then we analyze particle motion in the polar cap and show that NUT parameter can significantly change conditions for particle acceleration.Comment: 21 pages, 6 figures, accepted for publication in Ap

The characteristics of foreign educational systems

Personnel training is the main aspect in providing stability and increasing competitiveness of organization according to the current requirements of external and internal environment. The article shows the importance of learning foreign experience in personnel training, which is considered in this article in terms of Great Britain and Japan

The characteristics of foreign educational systems

Personnel training is the main aspect in providing stability and increasing competitiveness of organization according to the current requirements of external and internal environment. The article shows the importance of learning foreign experience in personnel training, which is considered in this article in terms of Great Britain and Japan

Leprosy in wild chimpanzees

Humans are considered as the main host for Mycobacterium leprae1, the aetiological agent of leprosy, but spillover has occurred to other mammals that are now maintenance hosts, such as nine-banded armadillos and red squirrels2,3. Although naturally acquired leprosy has also been described in captive nonhuman primates4-7, the exact origins of infection remain unclear. Here we describe leprosy-like lesions in two wild populations of western chimpanzees (Pan troglodytes verus) in Cantanhez National Park, Guinea-Bissau and Taï National Park, Côte d'Ivoire, West Africa. Longitudinal monitoring of both populations revealed the progression of disease symptoms compatible with advanced leprosy. Screening of faecal and necropsy samples confirmed the presence of M. leprae as the causative agent at each site and phylogenomic comparisons with other strains from humans and other animals show that the chimpanzee strains belong to different and rare genotypes (4N/O and 2F). These findings suggest that M. leprae may be circulating in more wild animals than suspected, either as a result of exposure to humans or other unknown environmental sources

The χ2\chi^2 - divergence and Mixing times of quantum Markov processes

We introduce quantum versions of the $\chi^2$-divergence, provide a detailed analysis of their properties, and apply them in the investigation of mixing times of quantum Markov processes. An approach similar to the one presented in [1-3] for classical Markov chains is taken to bound the trace-distance from the steady state of a quantum processes. A strict spectral bound to the convergence rate can be given for time-discrete as well as for time-continuous quantum Markov processes. Furthermore the contractive behavior of the $\chi^2$-divergence under the action of a completely positive map is investigated and contrasted to the contraction of the trace norm. In this context we analyse different versions of quantum detailed balance and, finally, give a geometric conductance bound to the convergence rate for unital quantum Markov processes