1,003 research outputs found
Observation of interspecies Feshbach resonances in an ultracold Rb-Cs mixture
We report on the observation of interspecies Feshbach resonances in an
ultracold, optically trapped mixture of Rb and Cs atoms. In a magnetic field
range up to 300 G we find 23 interspecies Feshbach resonances in the lowest
spin channel and 2 resonances in a higher channel of the mixture. The
extraordinarily rich Feshbach spectrum suggests the importance of different
partial waves in both the open and closed channels of the scattering problem
along with higher-order coupling mechanisms. Our results provide, on one hand,
fundamental experimental input to characterize the Rb-Cs scattering properties
and, on the other hand, identify possible starting points for the association
of ultracold heteronuclear RbCs molecules.Comment: 7 pages, 3 figures, 1 tabl
Supersymmetric Charged Clouds in AdS_5
We consider supersymmetric holographic flows that involve background gauge
fields dual to chemical potentials in the boundary field theory. We use a
consistent truncation of gauged N=8 supergravity in five dimensions and we give
a complete analysis of the supersymmetry conditions for a large family of
flows. We examine how the well-known supersymmetric flow between two fixed
points is modified by the presence of the chemical potentials and this yields a
new, completely smooth, solution that interpolates between two global AdS
spaces of different radii and with different values of the chemical potential.
We also examine some black-hole-like singular flows and a new
non-supersymmetric black hole solution. We comment on the interpretation of our
new solutions in terms of giant gravitons and discuss the implications of our
work for finding black-hole solutions in AdS geometries.Comment: 31 pages, 6 figures; minor corrections, updated reference
Arbitrary Spin Representations in de Sitter from dS/CFT with Applications to dS Supergravity
We present a simple group representation analysis of massive, and
particularly ``partially massless'', fields of arbitrary spin in de Sitter
spaces of any dimension. The method uses bulk to boundary propagators to relate
these fields to Euclidean conformal ones at one dimension lower. These results
are then used to revisit an old question: can a consistent de Sitter
supergravity be constructed, at least within its intrinsic horizon?Comment: 19 pages LaTex, references added, version to appear Nucl. Phys.
Excellent Rings with Singleton Formal Fibers
In this paper we construct a non complete excellent local ring A such that the natural map Spec Ă â Spec A is bijective
Experimental Evidence for Efimov Quantum States
Three interacting particles form a system which is well known for its complex
physical behavior. A landmark theoretical result in few-body quantum physics is
Efimov's prediction of a universal set of weakly bound trimer states appearing
for three identical bosons with a resonant two-body interaction. Surprisingly,
these states even exist in the absence of a corresponding two-body bound state
and their precise nature is largely independent of the particular type of the
two-body interaction potential. Efimov's scenario has attracted great interest
in many areas of physics; an experimental test however has not been achieved.
We report the observation of an Efimov resonance in an ultracold thermal gas of
cesium atoms. The resonance occurs in the range of large negative two-body
scattering lengths and arises from the coupling of three free atoms to an
Efimov trimer. We observe its signature as a giant three-body recombination
loss when the strength of the two-body interaction is varied near a Feshbach
resonance. This resonance develops into a continuum resonance at non-zero
collision energies, and we observe a shift of the resonance position as a
function of temperature. We also report on a minimum in the recombination loss
for positive scattering lengths, indicating destructive interference of decay
pathways. Our results confirm central theoretical predictions of Efimov physics
and represent a starting point from which to explore the universal properties
of resonantly interacting few-body systems.Comment: 8 pages, 4 figures, Proceedings of ICAP-2006 (Innsbruck
Supergravity Instabilities of Non-Supersymmetric Quantum Critical Points
Motivated by the recent use of certain consistent truncations of M-theory to
study condensed matter physics using holographic techniques, we study the
SU(3)-invariant sector of four-dimensional, N=8 gauged supergravity and compute
the complete scalar spectrum at each of the five non-trivial critical points.
We demonstrate that the smaller SU(4)^- sector is equivalent to a consistent
truncation studied recently by various authors and find that the critical point
in this sector, which has been proposed as the ground state of a holographic
superconductor, is unstable due to a family of scalars that violate the
Breitenlohner-Freedman bound. We also derive the origin of this instability in
eleven dimensions and comment on the generalization to other embeddings of this
critical point which involve arbitrary Sasaki-Einstein seven manifolds. In the
spirit of a resurging interest in consistent truncations, we present a formal
treatment of the SU(3)-invariant sector as a U(1)xU(1) gauged N=2 supergravity
theory coupled to one hypermultiplet.Comment: 46 page
Holographic RG Flows and Universal Structures on the Coulomb Branch of N=2 Supersymmetric Large n Gauge Theory
We report on our results of D3-brane probing a large class of generalised
type IIB supergravity solutions presented very recently in the literature. The
structure of the solutions is controlled by a single non-linear differential
equation. These solutions correspond to renormalisation group flows from pure
N=4 supersymmetric gauge theory to an N=2 gauge theory with a massive adjoint
scalar. The gauge group is SU(n) with n large. After presenting the general
result, we focus on one of the new solutions, solving for the specific
coordinates needed to display the explicit metric on the moduli space. We
obtain an appropriately holomorphic result for the coupling. We look for the
singular locus, and interestingly, the final result again manifests itself in
terms of a square root branch cut on the complex plane, as previously found for
a set of solutions for which the details are very different. This, together
with the existence of the single simple non-linear differential equation, is
further evidence in support of an earlier suggestion that there is a very
simple model --perhaps a matrix model with relation to the Calogero-Moser
integrable system-- underlying this gauge theory physics.Comment: 14 pages, LaTeX, 1 figur
N=1 de Sitter Supersymmetry Algebra
Recalling the universal covering group of de Sitter, the transformation
properties of the spinor fields and , in the ambient
space notation, are presented in this paper. The charge conjugation symmetry of
the de Sitter spinor field is then discussed in the above notation. Using this
spinor field and charge conjugation, de Sitter supersymmetry algebra in the
ambient space notation has been established. It is shown that a novel
dS-superalgebra can be attained by the use of spinor field and charge
conjugation in the ambient space notation.Comment: 8 pages, LaTeX, some details adde
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