194,020 research outputs found

    Wind braking of magnetars: to understand magnetar's multiwave radiation properties

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    Magnetars are proposed to be peculiar neutron stars powered by their super strong magnetic field. Observationally, anomalous X-ray pulsars and soft gamma-ray repeaters are believed to be magnetar candidates. While more and more multiwave observations of magnetars are available, unfortunately, we see accumulating failed predictions of the traditional magnetar model. These challenges urge rethinking of magnetar. Wind braking of magnetars is one of the alternative modelings. The release of magnetic energy may generate a particle outflow (i.e., particle wind), that results in both an anomalous X-ray luminosity and significantly high spindown rate. In this wind braking scenario, only strong multipole field is necessary for a magnetar (a strong dipole field is no longer needed). Wind braking of magnetars may help us to understand their multiwave radiation properties, including (1) Non-detection of magnetars in Fermi-LAT observations, (2) The timing behaviors of low magnetic field magnetars, (3) The nature of anti-glitches, (4) The criterion for magnetar's radio emission, etc. In the wind braking model of magentars, timing events of magnetars should always be accompanied by radiative events. It is worth noting that the wind engine should be the central point in the research since other efforts with any reasonable energy mechanism may also reproduce the results.Comment: 6 pages, 1 figure, submitted to conference proceeding of SMFNS2013 (Strong electromagnetic field and neutron stars 2013

    The timing behavior of magnetar Swift J1822.3-1606: timing noise or a decreasing period derivative?

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    The different timing results of the magnetar Swift J1822.3-1606 is analyzed and understood theoretically. It is pointed that different timing solutions are caused not only by timing noise, but also that the period derivative is decreasing after outburst. Both the decreasing period derivative and the large timing noise may be originated from wind braking of the magnetar. Future timing of Swift J1822.3-1606 will help us make clear whether its period derivative is decreasing with time or not.Comment: 5 pages, 1 figure. Accepted by Research in Astronomy and Astrophysic

    New results of intersection numbers on moduli spaces of curves

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    We present a series of new results we obtained recently about the intersection numbers of tautological classes on moduli spaces of curves, including a simple formula of the n-point functions for Witten's τ\tau classes, an effective recursion formula to compute higher Weil-Petersson volumes, several new recursion formulae of intersection numbers and our proof of a conjecture of Itzykson and Zuber concerning denominators of intersection numbers. We also present Virasoro and KdV properties of generating functions of general mixed κ\kappa and ψ\psi intersections.Comment: 9 pages, a brief surve

    Loop Expansion in Light-Cone ϕ4\phi^4 Field Theory

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    A loop expansion is implemented based on the path integral quantization of the light-cone ϕ4\phi^4 field theory in 1+1 dimensions. The effective potential as a function of the zero-mode field ω\omega is calculated up to two loop order and its derivative with respect to ω\omega is used to determine the vacuum expectation value of the field ϕ\phi. The critical coupling constant at the spontaneous symmetry breakdown is consistent with that obtained in the ordinary instant-form field theory. The critical exponents which describe the behavior of the susceptibility and the vacuum expectation value of ϕ\phi near the critical point are evaluated from the effective potential. The one loop diagrams for the connected Green's function are calculated in momentum space. The relevant equal-time correlation function is shown to be closely related.Comment: 12 pages, plain Tex, 1 table, 3 figures available from [email protected] , accepted by Phys. Rev.