4,663 research outputs found
The holographic supersymmetric Renyi entropy in five dimensions
We compute the supersymmetric Renyi entropy across an entangling three-sphere
for five-dimensional superconformal field theories using localization. For a
class of USp(2N) gauge theories we construct a holographic dual 1/2 BPS black
hole solution of Euclidean Romans F(4) supergravity. The large N limit of the
gauge theory results agree perfectly with the supergravity computations.Comment: 19 page
Localization on Three-Manifolds
We consider supersymmetric gauge theories on Riemannian three-manifolds with
the topology of a three-sphere. The three-manifold is always equipped with an
almost contact structure and an associated Reeb vector field. We show that the
partition function depends only on this vector field, giving an explicit
expression in terms of the double sine function. In the large N limit our
formula agrees with a recently discovered two-parameter family of dual
supergravity solutions. We also explain how our results may be applied to prove
vortex-antivortex factorization. Finally, we comment on the extension of our
results to three-manifolds with non-trivial fundamental group.Comment: 34 pages; v2: discussion of vortex factorization added; v3: minor
correction
Performance Bounds for Parameter Estimation under Misspecified Models: Fundamental findings and applications
Inferring information from a set of acquired data is the main objective of
any signal processing (SP) method. In particular, the common problem of
estimating the value of a vector of parameters from a set of noisy measurements
is at the core of a plethora of scientific and technological advances in the
last decades; for example, wireless communications, radar and sonar,
biomedicine, image processing, and seismology, just to name a few. Developing
an estimation algorithm often begins by assuming a statistical model for the
measured data, i.e. a probability density function (pdf) which if correct,
fully characterizes the behaviour of the collected data/measurements.
Experience with real data, however, often exposes the limitations of any
assumed data model since modelling errors at some level are always present.
Consequently, the true data model and the model assumed to derive the
estimation algorithm could differ. When this happens, the model is said to be
mismatched or misspecified. Therefore, understanding the possible performance
loss or regret that an estimation algorithm could experience under model
misspecification is of crucial importance for any SP practitioner. Further,
understanding the limits on the performance of any estimator subject to model
misspecification is of practical interest. Motivated by the widespread and
practical need to assess the performance of a mismatched estimator, the goal of
this paper is to help to bring attention to the main theoretical findings on
estimation theory, and in particular on lower bounds under model
misspecification, that have been published in the statistical and econometrical
literature in the last fifty years. Secondly, some applications are discussed
to illustrate the broad range of areas and problems to which this framework
extends, and consequently the numerous opportunities available for SP
researchers.Comment: To appear in the IEEE Signal Processing Magazin
Cost standards in Shoe manufacturing: A necessary guide to profit-making management
To take up now the first of the points that I wish to discuss today: I think the average manufacturer has laid too much stress on the use of costs as a basis for determining selling prices, when, as a matter of fact, costs should be used primarily to determine the base below which there is no profit
Herbert S. Klein, The American Finances of the Spanish Empire: Royal Income and Expenditures in Colonial Mexico, Peru, and Bolivia, 1680-1809
Supersymmetric solutions to Euclidean Romans supergravity
We study Euclidean Romans supergravity in six dimensions with a non-trivial
Abelian R-symmetry gauge field. We show that supersymmetric solutions are in
one-to-one correspondence with solutions to a set of differential constraints
on an SU(2) structure. As an application of our results we (i) show that this
structure reduces at a conformal boundary to the five-dimensional rigid
supersymmetric geometry previously studied by the authors, (ii) find a general
expression for the holographic dual of the VEV of a BPS Wilson loop, matching
an exact field theory computation, (iii) construct holographic duals to
squashed Sasaki-Einstein backgrounds, again matching to a field theory
computation, and (iv) find new analytic solutions.Comment: 31 pages; v2: published version (with reference added
Supersymmetric gauge theories on five-manifolds
We construct rigid supersymmetric gauge theories on Riemannian
five-manifolds. We follow a holographic approach, realizing the manifold as the
conformal boundary of a six-dimensional bulk supergravity solution. This leads
to a systematic classification of five-dimensional supersymmetric backgrounds
with gravity duals. We show that the background metric is furnished with a
conformal Killing vector, which generates a transversely holomorphic foliation
with a transverse Hermitian structure. Moreover, we prove that any such metric
defines a supersymmetric background. Finally, we construct supersymmetric
Lagrangians for gauge theories coupled to arbitrary matter on such backgrounds.Comment: 35 pages: v2: minor corrections and references added. Published
versio
Supersymmetric gauge theories on squashed five-spheres and their gravity duals
We construct the gravity duals of large N supersymmetric gauge theories
defined on squashed five-spheres with SU(3) x U(1) symmetry. These five-sphere
backgrounds are continuously connected to the round sphere, and we find a
one-parameter family of 3/4 BPS deformations and a two-parameter family of
(generically) 1/4 BPS deformations. The gravity duals are constructed in
Euclidean Romans F(4) gauged supergravity in six dimensions, and uplift to
massive type IIA supergravity. We holographically renormalize the Romans
theory, and use our general result to compute the renormalized on-shell actions
for the solutions. The results agree perfectly with the large N limit of the
dual gauge theory partition function, which we compute using large N matrix
model techniques. In addition we compute BPS Wilson loops in these backgrounds,
both in supergravity and in the large N matrix model, again finding precise
agreement. Finally, we conjecture a general formula for the partition function
on any five-sphere background, which for fixed gauge theory depends only on a
certain supersymmetric Killing vector.Comment: 63 pages, no figures; v2: minor corrections and reference adde
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