1,181 research outputs found
Étude du Chrome Comme Liaison Métallique Antidiffusante Entre Uranium et Aluminium. EUR 413. = Study of Chrome as an Antidiffusing Metal Bond between Uranium and Aluminum. EUR 413.
Higher Spin Black Holes in Three Dimensions: Comments on Asymptotics and Regularity
In the context of (2+1)--dimensional SL(N,R)\times SL(N,R) Chern-Simons theory we explore issues related to regularity and asymptotics on the solid torus, for stationary and circularly symmetric solutions. We display and solve all necessary conditions to ensure a regular metric and metric-like higher spin fields. We prove that holonomy conditions are necessary but not sufficient conditions to ensure regularity, and that Hawking conditions do not necessarily follow from them. Finally we give a general proof that once the chemical potentials are turn on -- as demanded by regularity -- the asymptotics cannot be that of Brown-Henneaux
Sistema sulco/camalhão para culturas em rotação ao arroz em áreas de várzeas do Rio Grande do Sul.
bitstream/item/30805/1/circular-54.pd
A Non-Relativistic Weyl Anomaly
We examine the Weyl anomaly for a four-dimensional z=3 Lifshitz scalar
coupled to Horava's theory of anisotropic gravity. We find a one-loop
break-down of scale-invariance at second order in the gravitational background.Comment: LaTeX, 23 pages, no figures, JHEP style; v2: typos fixed to match the
published versio
Second-Order Formalism for 3D Spin-3 Gravity
A second-order formalism for the theory of 3D spin-3 gravity is considered.
Such a formalism is obtained by solving the torsion-free condition for the spin
connection \omega^a_{\mu}, and substituting the result into the action
integral. In the first-order formalism of the spin-3 gravity defined in terms
of SL(3,R) X SL(3,R) Chern-Simons (CS) theory, however, the generalized
torsion-free condition cannot be easily solved for the spin connection, because
the vielbein e^a_{\mu} itself is not invertible. To circumvent this problem,
extra vielbein-like fields e^a_{\mu\nu} are introduced as a functional of
e^a_{\mu}. New set of affine-like connections \Gamma_{\mu M}^N are defined in
terms of the metric-like fields, and a generalization of the Riemann curvature
tensor is also presented. In terms of this generalized Riemann tensor the
action integral in the second-order formalism is expressed. The transformation
rules of the metric and the spin-3 gauge field under the generalized
diffeomorphims are obtained explicitly. As in Einstein gravity, the new
affine-like connections are related to the spin connection by a certain gauge
transformation, and a gravitational CS term expressed in terms of the new
connections is also presented.Comment: 40 pages, no figures. v2:references added, coefficients of eqs in
apppendix D corrected, minor typos also corrected, v3:Version accepted for
publication in Classical and Quantum Gravit
Violation of Energy Bounds in Designer Gravity
We continue our study of the stability of designer gravity theories, where
one considers anti-de Sitter gravity coupled to certain tachyonic scalars with
boundary conditions defined by a smooth function W. It has recently been argued
there is a lower bound on the conserved energy in terms of the global minimum
of W, if the scalar potential arises from a superpotential P and the scalar
reaches an extremum of P at infinity. We show, however, there are
superpotentials for which these bounds do not hold.Comment: 16 pages, 4 figures, v2: discussion of vacuum decay included, typos
corrected, reference adde
Fission half-lives of super-heavy nuclei in a microscopic approach
A systematic study of 160 heavy and super-heavy nuclei is performed in the
Hartree-Fock-Bogoliubov approach with the finite range and density dependent
Gogny force with the D1S parameter set. We show calculations in several
approximations: with axially symmetric and reflexion symmetric wave functions,
with axially symmetric and non-reflexion symmetric wave functions and finally
some representative examples with triaxial wave functions are also discussed.
Relevant properties of the ground state and along the fission path are
thoroughly analyzed. Fission barriers, Q-factors and lifetimes with
respect to fission and -decay as well as other observables are
discussed. Larger configuration spaces and more general HFB wave functions as
compared to previous studies provide a very good agreement with the
experimental data.Comment: 26 pages, 15 figure
High-spin structures of 136Cs
Odd-odd 136Cs nuclei have been produced in the 18O + 208Pb and 12C + 238U
fusion-fission reactions and their gamma rays studied with the Euroball array.
The high-spin level scheme has been built up to ~ 4.7 MeV excitation energy and
spin I ~ 16 hbar from the triple gamma-ray coincidence data. The configurations
of the three structures observed above ~ 2 MeV excitation energy are first
discussed by analogy with the proton excitations identified in the semi-magic
137Cs nucleus, which involve the three high-j orbits lying above the Z=50 gap,
pi g_{7/2}, pi d_{5/2} and pi h_{11/2}. This is confirmed by the results of
shell-model calculations performed in this work.Comment: 6 pages, 4 figures, 3 table
Diffeomorphisms and Holographic Anomalies
Using the relation between diffeomorphisms in the bulk and Weyl
transformations on the boundary we study the Weyl transformation properties of
the bulk metric on shell and of the boundary action. We obtain a universal
formula for one of the classes of trace anomalies in any even dimension in
terms of the parameters of the gravity action.Comment: 12 pages, harvma
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