158 research outputs found
A holographic proof of the strong subadditivity of entanglement entropy
When a quantum system is divided into subsystems, their entanglement
entropies are subject to an inequality known as "strong subadditivity". For a
field theory this inequality can be stated as follows: given any two regions of
space and , . Recently, a
method has been found for computing entanglement entropies in any field theory
for which there is a holographically dual gravity theory. In this note we give
a simple geometrical proof of strong subadditivity employing this holographic
prescription.Comment: 9 pages, 3 figure
The Jacobi orientation and the two-variable elliptic genus
We explain the relationship between the sigma orientation and Witten genus on
the one hand and the two-variable elliptic genus on the other. We show that if
E is an elliptic spectrum, then the Theorem of the Cube implies the existence
of canonical SU-orientation of the associated spectrum of Jacobi forms. In the
case of the elliptic spectrum associated to the Tate curve, this gives the
two-variable elliptic genus. We also show that the two-variable genus arises as
an instance of the circle-equivariant sigma orientation.Comment: Revised to better exhibit complex orientation of
MSU^(CP^\infty_{-infty}
Tensors Mesons in AdS/QCD
We explore tensor mesons in AdS/QCD focusing on f2 (1270), the lightest
spin-two resonance in QCD. We find that the f2 mass and the partial width for
f2 -> gamma gamma are in very good agreement with data. In fact, the
dimensionless ratio of these two quantities comes out within the current
experimental bound. The result for this ratio depends only on Nc and Nf, and
the quark and glueball content of the operator responsible for the f2; more
importantly, it does not depend on chiral symmetry breaking and so is both
independent of much of the arbitrariness of AdS/QCD and completely out of reach
of chiral perturbation theory. For comparison, we also explore f2 -> pi pi,
which because of its sensitivity to the UV corrections has much more
uncertainty. We also calculate the masses of the higher spin resonances on the
Regge trajectory of the f2, and find they compare favorably with experiment.Comment: 21 pages, 1 figure; Li's correcte
Predicting Audio Advertisement Quality
Online audio advertising is a particular form of advertising used abundantly
in online music streaming services. In these platforms, which tend to host tens
of thousands of unique audio advertisements (ads), providing high quality ads
ensures a better user experience and results in longer user engagement.
Therefore, the automatic assessment of these ads is an important step toward
audio ads ranking and better audio ads creation. In this paper we propose one
way to measure the quality of the audio ads using a proxy metric called Long
Click Rate (LCR), which is defined by the amount of time a user engages with
the follow-up display ad (that is shown while the audio ad is playing) divided
by the impressions. We later focus on predicting the audio ad quality using
only acoustic features such as harmony, rhythm, and timbre of the audio,
extracted from the raw waveform. We discuss how the characteristics of the
sound can be connected to concepts such as the clarity of the audio ad message,
its trustworthiness, etc. Finally, we propose a new deep learning model for
audio ad quality prediction, which outperforms the other discussed models
trained on hand-crafted features. To the best of our knowledge, this is the
first large-scale audio ad quality prediction study.Comment: WSDM '18 Proceedings of the Eleventh ACM International Conference on
Web Search and Data Mining, 9 page
Dynamics of First Order Transitions with Gravity Duals
A first order phase transition usually proceeds by nucleating bubbles of the
new phase which then rapidly expand. In confining gauge theories with a gravity
dual, the deconfined phase is often described by a black hole. If one starts in
this phase and lowers the temperature, the usual description of how the phase
transition proceeds violates the area theorem. We study the dynamics of this
phase transition using the insights from the dual gravitational description,
and resolve this apparent contradiction.Comment: 11 pages, 1 figure. v2: minor clarifications, reference adde
Echoes of a Hidden Valley at Hadron Colliders
We consider examples of ``hidden-valley'' models, in which a new confining
gauge group is added to the standard model. Such models often arise in string
constructions, and elsewhere. The resulting (electrically-neutral) bound states
can have low masses and long lifetimes, and could be observed at the LHC and
Tevatron. Production multiplicities are often large. Final states with heavy
flavor are common; lepton pairs, displaced vertices and/or missing energy are
possible. Accounting for LEP constraints, we find LHC production cross-sections
typically in the 1-100 fb range, though they can be larger. It is possible the
Higgs boson could be discovered at the Tevatron through rare decays to the new
particles.Comment: 5 pages, 5 figures (v2: minor improvements, one added reference, no
substantial changes
Patterns of Duality in N=1 SUSY Gauge Theories
We study the patterns in the duality of a wide class of N=1 supersymmetric
gauge theories in four dimensions. We present many new generalizations of the
classic duality models of Kutasov and Schwimmer, which have themselves been
generalized numerous times in works of Intriligator, Leigh and the present
authors. All of these models contain one or two fields in a two-index tensor
representation, along with fields in the defining representation. The
superpotential for the two-index tensor(s) resembles A_k or D_k singularity
forms, generalized from numbers to matrices. Looking at the ensemble of these
models, classifying them by superpotential, gauge group, and ``level'' -- for
terminology we appeal to the architecture of a typical European-style theatre
-- we identify emerging patterns and note numerous interesting puzzles.Comment: 34 pages, 4 figures, uses harvmac and table
Stability in Einstein-Scalar Gravity with a Logarithmic Branch
We investigate the non-perturbative stability of asymptotically anti-de
Sitter gravity coupled to tachyonic scalar fields with mass saturating the
Breitenlohner-Freedman bound. Such "designer gravity" theories admit a large
class of boundary conditions at asymptotic infinity. At this mass, the
asymptotic behavior of the scalar field develops a logarithmic branch, and
previous attempts at proving a minimum energy theorem failed due to a large
radius divergence in the spinor charge. In this paper, we finally resolve this
issue and derive a lower bound on the conserved energy. Just as for masses
slightly above the BF bound, a given scalar potential can admit two possible
branches of the corresponding superpotential, one analytic and one
non-analytic. The key point again is that existence of the non-analytic branch
is necessary for the energy bound to hold. We discuss several AdS/CFT
applications of this result, including the use of double-trace deformations to
induce spontaneous symmetry breaking.Comment: 31 pages, 7 figure
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