2,042 research outputs found
Energy-Momentum Complex in M\o ller's Tetrad Theory of Gravitation
M\o ller's Tetrad Theory of Gravitation is examined with regard to the
energy-momentum complex. The energy-momentum complex as well as the
superpotential associated with M\o ller's theory are derived. M\o ller's field
equations are solved in the case of spherical symmetry. Two different
solutions, giving rise to the same metric, are obtained. The energy associated
with one solution is found to be twice the energy associated with the other.
Some suggestions to get out of this inconsistency are discussed at the end of
the paper.Comment: LaTeX2e with AMS-LaTeX 1.2, 13 page
Kerr-Schild type initial data for black holes with angular momenta
Generalizing previous work we propose how to superpose spinning black holes
in a Kerr-Schild initial slice. This superposition satisfies several physically
meaningful limits, including the close and the far ones. Further we consider
the close limit of two black holes with opposite angular momenta and explicitly
solve the constraint equations in this case. Evolving the resulting initial
data with a linear code, we compute the radiated energy as a function of the
masses and the angular momenta of the black holes.Comment: 13 pages, 3 figures. Revised version. To appear in Classical and
Quantum Gravit
Ab initio and Effective field Study of V doped TiO2
Using the effective field theory (EFT), the Curie temperature of V- doped rutile TiO2 has been determined. The exchange coupling used in the calculation has been deduced from first principal calculation based on the density functional theory with the local spin density approximation (LSDA). We also showed that V- doped rutile TiO2 is half metallic and the hybridization is between the V 3d states and the nearest-neighbouring O 2p states. The results from ab initio calculation showed that for weak holes concentrations the ferromagnetism is due to the double exchange, while, for higher hole concentration it comes from the RKKY exchange interaction. In addition, we show via effective field theory calculations that the transition from the nonmagnetic (NM) to the ferromagnetic (FM) phase is marked by the magnetic percolation. Magnetization as a function of the temperature for different values of the hole concentration, nc, is also given
Gravitational Smearing of Minimal Supersymmetric Unification Predictions
A short and mean paper.Comment: 10 pages total + 1 postscript figure (included), revised: all lines
are TRULY < 70 characters long (try it!); LBL-32905, UCB-PTH-92/3
Characterization of Live-Attenuated Powassan Virus Vaccine Candidates Identifies an Efficacious Prime-Boost Strategy for Mitigating Powassan Virus Disease in a Murine Model
Powassan virus (POWV) is an emerging tick-borne virus and cause of lethal encephalitis in humans. The lack of treatment or prevention strategies for POWV disease underscores the need for an effective POWV vaccine. Here, we took two independent approaches to develop vaccine candidates. First, we recoded the POWV genome to increase the dinucleotide frequencies of CpG and UpA to potentially attenuate the virus by raising its susceptibility to host innate immune factors, such as the zinc-finger antiviral protein (ZAP). Secondly, we took advantage of the live-attenuated yellow fever virus vaccine 17D strain (YFV-17D) as a vector to express the structural genes pre-membrane (prM) and envelope (E) of POWV. The chimeric YFV-17D-POWV vaccine candidate was further attenuated for in vivo application by removing an N-linked glycosylation site within the nonstructural protein (NS)1 of YFV-17D. This live-attenuated chimeric vaccine candidate significantly protected mice from POWV disease, conferring a 70% survival rate after lethal challenge when administered in a homologous two-dose regimen. Importantly, when given in a heterologous prime-boost vaccination scheme, in which vaccination with the initial chimeric virus was followed by a protein boost with the envelope protein domain III (EDIII), 100% of the mice were protected without showing any signs of morbidity. Combinations of this live-attenuated chimeric YFV-17D-POWV vaccine candidate with an EDIII protein boost warrant further studies for the development of an effective vaccine strategy for the prevention of POWV disease
Free field realization of superstring theory on AdS3
The Coulomb gas representation of expectation values in SU(2) conformal field
theory developed by Dotsenko is extended to the SL(2,R) WZW model and applied
to bosonic string theory on AdS3 and to Type II superstrings on AdS3 x N. The
spectral flow symmetry is included in the free field realization of vertex
operators creating superstring states of both Ramond and Neveu-Schwarz sectors.
Conjugate representations for these operators are constructed and a background
charge prescription is designed to compute correlation functions. Two and three
point functions of bosonic and fermionic string states in arbitrary winding
sectors are calculated. Scattering amplitudes that violate winding number
conservation are also discussed.Comment: 40 pages, typos corrected, references added, minor changes in
presentation and details completed in the calculation of the R sector 2-point
function. Version to appear in JHE
A hyperbolic slicing condition adapted to Killing fields and densitized lapses
We study the properties of a modified version of the Bona-Masso family of
hyperbolic slicing conditions. This modified slicing condition has two very
important features: In the first place, it guarantees that if a spacetime is
static or stationary, and one starts the evolution in a coordinate system in
which the metric coefficients are already time independent, then they will
remain time independent during the subsequent evolution, {\em i.e.} the lapse
will not evolve and will therefore not drive the time lines away from the
Killing direction. Second, the modified condition is naturally adapted to the
use of a densitized lapse as a fundamental variable, which in turn makes it a
good candidate for a dynamic slicing condition that can be used in conjunction
with some recently proposed hyperbolic reformulations of the Einstein evolution
equations.Comment: 11 page
Effective theories of scattering with an attractive inverse-square potential and the three-body problem
A distorted-wave version of the renormalisation group is applied to
scattering by an inverse-square potential and to three-body systems. In
attractive three-body systems, the short-distance wave function satisfies a
Schroedinger equation with an attractive inverse-square potential, as shown by
Efimov. The resulting oscillatory behaviour controls the renormalisation of the
three-body interactions, with the renormalisation-group flow tending to a limit
cycle as the cut-off is lowered. The approach used here leads to single-valued
potentials with discontinuities as the bound states are cut off. The
perturbations around the cycle start with a marginal term whose effect is
simply to change the phase of the short-distance oscillations, or the
self-adjoint extension of the singular Hamiltonian. The full power counting in
terms of the energy and two-body scattering length is constructed for
short-range three-body forces.Comment: 19 pages (RevTeX), 2 figure
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