4,032 research outputs found
Aritmética topológica real
Análogamente al hecho de que a conjuntos coordinables se les asocia un número cardinal, y a conjuntos ordenados isomorfos un número ordinal, a espacios topológicos homeomorfos les asociamos un ente que podemos llamar número topológico . Al definir sobre estos números una ordenación y una aritmética aparecen analogías y diferencias con aritmética usual de los números naturales . En este trabajo se estudian estos hechos para ciertos números topológicos extraídos del espacio de los números reales
Supersymmetry and Polytopes
We make an imaginative comparison between the Minimal Supersymmetric Standard
Model and the 24-cell polytope in four dimensions, the Octacube.Comment: Presented to the Workshop on Geometry and Physics: Supersymmetry.
Bilbao, Spain. May 200
Gauge theory in dimension
We first review the notion of a -manifold, defined in terms of a
principal ("gauge") bundle over a -dimensional manifold, before
discussing their relation to supergravity. In a second thread, we focus on
associative submanifolds and present their deformation theory. In particular,
we elaborate on a deformation problem with coassociative boundary condition.
Its space of infinitesimal deformations can be identified with the solution
space of an elliptic equation whose index is given by a topological formula.Comment: 15 page
Seasonal Dependence in the Solar Neutrino Flux
MSW solutions of the solar neutrino problem predict a seasonal dependence of
the zenith angle distribution of the event rates, due to the non-zero latitude
at the Super-Kamiokande site. We calculate this seasonal dependence and compare
it with the expectations in the no-oscillation case as well as just-so
scenario, in the light of the latest Super-Kamiokande 708-day data. The
seasonal dependence can be sizeable in the large mixing angle MSW solution and
would be correlated with the day-night effect. This may be used to discriminate
between MSW and just-so scenarios and should be taken into account in refined
fits of the data.Comment: 4 pages, latex, RevTeX, two postscript figure
The Classification of Highly Supersymmetric Supergravity Solutions
The spinorial geometry method is an effective method for constructing
systematic classifications of supersymmetric supergravity solutions. Recent
work on analysing highly supersymmetric solutions in type IIB supergravity
using this method is reviewed [arXiv:hep-th/0606049, arXiv:0710.1829]. It is
shown that all supersymmetric solutions of IIB supergravity with more than 28
Killing spinors are locally maximally supersymmetric.Comment: 23 pages, latex. To appear in the proceedings of the Special Metrics
and Supersymmetry conference at Universidad del Pais Vasco, May 2008.
References correcte
A Multiwavelength Study of Young Massive Star-Forming Regions. III. Mid-Infrared Emission
We present mid-infrared (MIR) observations, made with the TIMMI2 camera on
the ESO 3.6 m telescope, toward 14 young massive star-forming regions. All
regions were imaged in the N band, and nine in the Q band, with an angular
resolution of ~ 1 arcsec. Typically, the regions exhibit a single or two
compact sources (with sizes in the range 0.008-0.18 pc) plus extended diffuse
emission. The Spitzer-Galactic Legacy Infrared Mid-Plane Survey Extraordinaire
images of these regions show much more extended emission than that seen by
TIMMI2, and this is attributed to polycyclic aromatic hydrocarbon (PAH) bands.
For the MIR sources associated with radio continuum radiation (Paper I) there
is a close morphological correspondence between the two emissions, suggesting
that the ionized gas (radio source) and hot dust (MIR source) coexist inside
the H II region. We found five MIR compact sources which are not associated
with radio continuum emission, and are thus prime candidates for hosting young
massive protostars. In particular, objects IRAS 14593-5852 II (only detected at
17.7 microns) and 17008-4040 I are likely to be genuine O-type protostellar
objects. We also present TIMMI2 N-band spectra of eight sources, all of which
are dominated by a prominent silicate absorption feature (~ 9.7 microns). From
these data we estimate column densities in the range (7-17)x10^22 cm^-2, in
good agreement with those derived from the 1.2 mm data (Paper II). Seven
sources show bright [Ne II] line emission, as expected from ionized gas
regions. Only IRAS 123830-6128 shows detectable PAH emission at 8.6 and 11.3
microns.Comment: Published in ApJ. 15 pages, 6 figures. Formatted with emulateapj; v2:
Minor language changes to match the published versio
Circular strings, wormholes and minimum size
The quantization of circular strings in an anti-de Sitter background
spacetime is performed, obtaining a discrete spectrum for the string mass. A
comparison with a four-dimensional homogeneous and isotropic spacetime coupled
to a conformal scalar field shows that the string radius and the scale factor
have the same classical solutions and that the quantum theories of these two
models are formally equivalent. However, the physically relevant observables of
these two systems have different spectra, although they are related to each
other by a specific one-to-one transformation. We finally obtain a discrete
spectrum for the spacetime size of both systems, which presents a nonvanishing
lower bound.Comment: 11 pages, LaTeX2e, minor change
Thermalization of particle detectors: The Unruh effect and its reverse
11 pags., 3 figs., app.We study the anti-Unruh effect in general stationary scenarios. We find that, for accelerated trajectories, a particle detector coupled to a Kubo-Martin-Schwinger (KMS) state of a quantum field can cool down (click less often) as the KMS temperature increases. Remarkably, this is so even when the detector is switched on adiabatically for infinitely long times. We also show that the anti-Unruh effect is characteristic of accelerated detectors and cannot appear for inertially moving detectors (e.g., in a thermal bath). © 2016 American Physical SocietyL. J. G. was partially supported by the Spanish MINECO
through Project No. FIS2014-54800-C2-2 (with FEDER
contribution). E. M.-M. acknowledges the funding of the
NSERC Discovery program.Peer Reviewe
- …