338 research outputs found
Quasi-Periodic Variations in X-ray Emission and Long-Term Radio Observations: Evidence for a Two-Component Jet in Sw J1644+57
The continued observations of Sw J1644+57 in X-ray and radio bands
accumulated a rich data set to study the relativistic jet launched in this
tidal disruption event. The X-ray light curve of Sw J1644+57 from 5-30 days
presents two kinds of quasi-periodic variations: a 200 second quasi-periodic
oscillation (QPO) and a 2.7-day quasi-periodic variation. The latter has been
interpreted by a precessing jet launched near the Bardeen-Petterson radius of a
warped disk. Here we suggest that the 200s QPO could be associated with
a second, narrower jet sweeping the observer line-of-sight periodically, which
is launched from a spinning black hole in the misaligned direction with respect
to the black hole's angular momentum. In addition, we show that this
two-component jet model can interpret the radio light curve of the event,
especially the re-brightening feature starting days after the
trigger. From the data we infer that inner jet may have a Lorentz factor of
and a kinetic energy of , while the outer jet may have a Lorentz factor of
and a kinetic energy of .Comment: 11 pages, 7 figures, accepted for publication in Ap
Vortex-Antivortex Lattices in a Holographic Superconductor
We employ the Einstein-Abelian-Higgs theory to investigate the structure of
vortex-antivortex lattices within a superconductor driven by spatial periodic
magnetic fields. By adjusting the parameters of the external magnetic field,
including the period () and the amplitude (), various
distinct vortex states emerge. These states encompass the Wigner
crystallization state, the vortex cluster state, and the suppressed state.
Additionally, we present a comprehensive phase diagram to demarcate the
specific regions where these structures emerge, contributing to our
understanding of superconductivity in complex magnetic environments
Giant vortex in a fast rotating holographic superfluid
In a holographic superfluid disk, when the rotational velocity is large
enough, we find a giant vortex will form in the center of the system by merging
several single charge vortices at some specific rotational velocity, with a
phase stratification phenomenon for the order parameter. The formation of a
giant vortex can be explained as there is not enough space for a standard
vortex lattice. Keep increasing the rotational velocity the giant vortex will
disappear and there will be an appearance of a superfluid ring. In the giant
vortex region, the number of vortices measured from winding number and
rotational velocity always satisfies the linear Feynman relation. However, when
the superfluid ring starts to appear, the number of vortices in the disk will
decrease though the rotational velocity is increasing, where most of the order
parameter is suppressed
Structural phase transition and its critical dynamics from holography
We introduce a gravitational lattice theory defined in an AdS black hole
background that provides a holographic dual description of the linear-to-zigzag
structural phase transition, characterized by the spontaneous breaking of
parity symmetry observed in, e.g., confined Coulomb crystals. The transition
from the high-symmetry linear phase to the broken-symmetry doubly-degenerate
zigzag phase can be driven by quenching the coupling between adjacent sites
through the critical point. An analysis of the equilibrium correlation length
and relaxation time reveals mean-field critical exponents. We explore the
nonequilibrium phase transition dynamics leading to kink formation. The kink
density obeys universal scaling laws in the limit of slow quenches, described
by the Kibble-Zurek mechanism (KZM), and at fast quenches, characterized by a
universal breakdown of the KZM.Comment: 10 pages, 11 figure
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