4,249 research outputs found
On Companion-Induced Off-Center Supernova-Like Explosions
We suggest that a neutron star with a strong magnetic field, spiraling into
the envelope of a companion star, can generate a ``companion induced SN-like
off-center explosion". The strongly magnetized neutron star ("magnetar") is
born in a supernova explosion before entering into an expanding envelope of a
supergiant companion. If the neutron star collapses into a black hole via the
hypercritical accretion during the spiral-in phase, a rapidly rotating black
hole with a strong magnetic field at the horizon results. The Blandford-Znajek
power is sufficient to power a supernova-like event with the center of
explosion displaced from the companion core. The companion core, after
explosion, evolves into a C/O-white dwarf or a neutron star with a second
explosion. The detection of highly eccentric black-hole, C/O-white dwarf
binaries or the double explosion structures in the supernova remnants could be
an evidence of the proposed scenario.Comment: 5 page
Quasi-local charges and asymptotic symmetry generators
The quasi-local formulation of conserved charges through the off-shell
approach is extended to cover the asymptotic symmetry generators. By
introducing identically conserved currents which are appropriate for asymptotic
Killing vectors, we show that the asymptotic symmetry generators can be
understood as quasi-local charges. We also show that this construction is
completely consistent with the on-shell method.Comment: 19 pages; v2 typos fixe
Thermodynamic Volume and the Extended Smarr Relation
We continue to explore the scaling transformation in the reduced action
formalism of gravity models. As an extension of our construction, we consider
the extended forms of the Smarr relation for various black holes, adopting the
cosmological constant as the bulk pressure as in some literatures on black
holes. Firstly, by using the quasi-local formalism for charges, we show that,
in a general theory of gravity, the volume in the black hole thermodynamics
could be defined as the thermodynamic conjugate variable to the bulk pressure
in such a way that the first law can be extended consistently. This, so called,
thermodynamic volume can be expressed explicitly in terms of the metric and
field variables. Then, by using the scaling transformation allowed in the
reduced action formulation, we obtain the extended Smarr relation involving the
bulk pressure and the thermodynamic volume. In our approach, we do not resort
to Euler's homogeneous scaling of charges while incorporating the would-be
hairy contribution without any difficulty.Comment: 1+21 pages, plain LaTeX; v2 typo fixed and references adde
Nonmonotonic behavior of resistance in a superconductor-Luttinger liquid junction
Transport through a superconductor-Luttinger liquid junction is considered.
When the interaction in the Luttinger liquid is repulsive, the resistance of
the junction with a sufficiently clean interface shows nonmonotonic
temperature- or voltage-dependence due to the competition between the
superconductivity and the repulsive interaction. The result is discussed in
connection with recent experiments on single-wall carbon nanotubes in contact
with superconducting leads.Comment: Revtex4, 2 eps figure files, slightly revised from an earlier version
submitted to PRL on 2001.12.
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