5,800 research outputs found
Fast radio bursts and their gamma-ray or radio afterglows as Kerr-Newman black hole binaries
Fast radio bursts (FRBs) are radio transients lasting only about a few
milliseconds. They seem to occur at cosmological distances. We propose that
these events can be originated in the collapse of the magnetosphere of
Kerr-Newman black holes (KNBHs). We show that the closed orbits of charged
particles in the magnetosphere of these objects are unstable. After examining
the dependencies on the specific charge of the particle and the spin and charge
of the KNBH, we conclude that the resulting timescale and radiation mechanism
fit well with the extant observations of FRBs. Furthermore, we argue that the
merger of a KNBH binary is one of the plausible central engines for potential
gamma-ray or radio afterglow following a certain FRBs, and can also account for
gravitational wave (GW) events like GW 150914. Our model leads to predictions
that can be tested by combined multi-wavelength electromagnetic and GW
observations.Comment: 6 pages, 4 figures, accepted for publication in Ap
Generation of Two-Flavor Vortex Atom Laser from a Five-State Medium
Two-flavor atom laser in a vortex state is obtained and analyzed via
electromagnetically induced transparency (EIT) technique in a five-level
type system by using two probe lights with -directional orbital angular
momentum , respectively. Together with the original transfer
technique of quantum states from light to matter waves, the present result can
be extended to generate continuous two-flavor vortex atom laser with
non-classical atoms.Comment: 5 pages, 1 figure; The previous version (v2) is a wrong one; this is
the published versio
Dynamics of Domain Wall in a Biaxial Ferromagnet With Spin-torque
The dynamics of the domain wall (DW) in a biaxial ferromagnet interacting
with a spin-polarized current are described by sine-gordon (SG) equation
coupled with Gilbert damping term in this paper. Within our frame-work of this
model, we obtain a threshold of the current in the motion of a single DW with
the perturbation theory on kink soliton solution to the corresponding
ferromagnetic system, and the threshold is shown to be dependent on the Gilbert
damping term. Also, the motion properties of the DW are discussed for the zero-
and nonzero-damping cases, which shows that our theory to describe the dynamics
of the DW are self-consistent.Comment: 7pages, 3figure
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