8,339 research outputs found
Comments on the four-dimensional effective theory for warped compactification
We derive four-dimensional effective theories for warped compactification of
the ten-dimensional IIB supergravity and the eleven-dimensional Horava-Witten
model. We show that these effective theories allow a much wider class of
solutions than the original higher-dimensional theories. In particular, the
effective theories have cosmological solutions in which the size of the
internal space decreases with the cosmic expansion in the Einstein frame. This
type of compactifying solutions are not allowed in the original
higher-dimensional theories. This result indicates that the effective
four-dimensional theories should be used with caution, if one regards the
higher-dimensional theories more fundamental.Comment: 21 pages, no figure. Minor errors are correcte
HBT Interferometry for Sonoluminescence Bubble
The two-photon correlation of the light pulse emitted from a sonoluminescence
bubble is discussed. It is shown that several important information about the
mechanism of light emission, such as the time-scale and the shape of the
emission region could be obtained from the HBT interferometry. We also argue
that such a measurement may serve to reject one of the two currently suggested
emission mechanisms, i.e., thermal process versus dynamical Casimir effect.Comment: 13 pages, RevTeX, 2 eps figures include
Field-Induced Effects of Anisotropic Magnetic Interactions in SrCu2(BO3)2
We observed a field-induced staggered magnetization in the 2D frustrated
dimer-singlet spin system SrCu2(BO3)2 by 11B NMR, from which the magnitudes of
the intradimer Dzyaloshinsky-Moriya interaction and the staggered g-tensor were
determined. These anisotropic interactions cause singlet-triplet mixing and
eliminate a quantum phase transition at the expected critical field Hc for gap
closing. They also provide a quantitative account for some puzzling phenomena
such as the onset of a uniform magnetization below the and the persistence of
the excitation gap above Hc. The gap was accurately determined from the
activation energy of the nuclear relaxation rate.Comment: 8 pages, 5 figures, published versio
Master field treatment of metric perturbations sourced by the trailing string
We present decoupled, separable forms of the linearized Einstein equations
sourced by a string trailing behind an external quark moving through a thermal
state of N=4 super-Yang-Mills theory. We solve these equations in the
approximations of large and small wave-numbers.Comment: 40 pages, 3 figure
Topological conformal field theory with a rational W potential and the dispersionless KP hierarchy
We present a new class of topological conformal field theories (TCFT)
characterized by a rational potential, which includes the minimal models of
A and D types as its subclasses. An explicit form of the potential is found
by solving the underlying dispersionless KP hierarchy in a particular small
phase space. We discuss also the dispersionless KP hierarchy in large phase
spaces by reformulating the hierarchy, and show that the potential takes a
universal form, which does not depend on a specific form of the solution in a
large space.Comment: 14 pages, plain TEX, KUL-TF-94/
New X-ray Clusters in the EMSS II: Optical Properties
We present optical images for 9 new clusters of galaxies we have found in a
reanalysis of the Einstein IPC images comprising the Extended Medium
Sensitivity Survey (EMSS). Based on the presence of a red sequence of galaxies
in a color-magnitude (CM) diagram, a redshift is estimated for each cluster.
Galaxy overdensities (cluster richnesses) are measured in each field using the
B_gc statistic which allows their plausible identification with the X-ray
emission. The nature of our X-ray detection algorithm suggests that most of
these clusters have low X-ray surface brightness (LSB) compared to the
previously known EMSS clusters. We compare the optical and X-ray observations
of these clusters with the well-studied Canadian Network for Observational
Cosmology (CNOC) subsample of the EMSS, and conclude that the new clusters
exhibit a similar range of optical richnesses, X-ray luminosities, and,
somewhat surprisingly, galaxy populations as the predominantly rich, relaxed
EMSS/CNOC clusters.Comment: Accepted to ApJ, 17 pages, 14 figures, uses emulateapj5.st
N-soliton solutions to the DKP equation and Weyl group actions
We study soliton solutions to the DKP equation which is defined by the Hirota
bilinear form, {\begin{array}{llll} (-4D_xD_t+D_x^4+3D_y^2)
\tau_n\cdot\tau_n=24\tau_{n-1}\tau_{n+1}, (2D_t+D_x^3\mp 3D_xD_y) \tau_{n\pm
1}\cdot\tau_n=0 \end{array} \quad n=1,2,.... where . The
-functions are given by the pfaffians of certain skew-symmetric
matrix. We identify one-soliton solution as an element of the Weyl group of
D-type, and discuss a general structure of the interaction patterns among the
solitons. Soliton solutions are characterized by skew-symmetric
constant matrix which we call the -matrices. We then find that one can have
-soliton solutions with being any number from to for some of
the -matrices having only nonzero entries in the upper
triangular part (the number of solitons obtained from those -matrices was
previously expected to be just ).Comment: 22 pages, 12 figure
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