23,227 research outputs found

### Gravity from Entanglement and RG Flow in a Top-down Approach

The duality between a $d$-dimensional conformal field theory with relevant
deformation and a gravity theory on an asymptotically AdS$_{d+1}$ geometry, has
become a suitable tool in the investigation of the emergence of gravity from
quantum entanglement in field theory. Recently, we have tested the duality
between the mass-deformed ABJM theory and asymptotically AdS$_4$ gravity
theory, which is obtained from the KK reduction of the 11-dimensional
supergravity on the LLM geometry. In this paper, we extend the KK reduction
procedure beyond the linear order and establish non-trivial KK maps between
4-dimensional fields and 11-dimensional fluctuations. We rely on this
gauge/gravity duality to calculate the entanglement entropy by using the
Ryu-Takayanagi holographic formula and the path integral method developed by
Faulkner. We show that the entanglement entropies obtained using these two
methods agree when the asymptotically AdS$_4$ metric satisfies the linearized
Einstein equation with nonvanishing energy-momentum tensor for two scalar
fields. These scalar fields encode the information of the relevant deformation
of the ABJM theory. This confirms that the asymptotic limit of LLM geometry is
the emergent gravity of the quantum entanglement in the mass-deformed ABJM
theory with a small mass parameter. We also comment on the issue of the
relative entropy and the Fisher information in our setup.Comment: 42 pages, no figure, minor corrections, references adde

### Abelian Gauge Invariance of the WZ-type Coupling in ABJM Theory

We construct the interaction terms between the worldvolume fields of multiple
M2-branes and 3-form gauge field of 11-dimensional supergravity, in the context
of ABJM theory. The obtained Wess-Zumino-type coupling is simultaneously
invariant under the U$_{\textrm{L}}(N)\times$U$_{\textrm{R}}(N)$ non-Abelian
gauge transformation of the ABJM theory and the Abelian gauge transformation of
the 3-form field in 11-dimensional supergravity.Comment: 16 pages, minor corrections, published versio

### Exact Holography of the Mass-deformed M2-brane Theory

We test the holographic relation between the vacuum expectation values of
gauge invariant operators in ${\cal N} = 6$ ${\rm U}_k(N)\times {\rm
U}_{-k}(N)$ mass-deformed ABJM theory and the LLM geometries with
$\mathbb{Z}_k$ orbifold in 11-dimensional supergravity. To do that, we apply
the Kaluza-Klein reduction to construct a 4-dimensional gravity theory and
implement the holographic renormalization procedure. We obtain an exact
holographic relation for the vacuum expectation values of the chiral primary
operator with conformal dimension $\Delta = 1$, which is given by $\langle
{\cal O}^{(\Delta=1)}\rangle= N^{\frac32} \, f_{(\Delta=1)}$, for large $N$ and
$k=1$. Here factor $f_{(\Delta)}$ is independent of $N$. Our results involve
infinite number of exact dual relations for all possible supersymmetric Higgs
vacua and so provide a nontrivial test of gauge/gravity duality away from the
conformal fixed point. We also extend our results to the case of $k\ne 1$ for
LLM geometries represented by rectangular-shaped Young-diagrams.Comment: 6 pages, major corrections in section 3 and 4, references added,
title change

### Mass-deformed ABJM Theory and LLM Geometries: Exact Holography

We present a detailed account and extension of our claim in arXiv:1610.01490.
We test the gauge/gravity duality between the ${\cal N} = 6$ mass-deformed ABJM
theory with U$_k(N)\times$U$_{-k}(N)$ gauge symmetry and the 11-dimensional
supergravity on LLM geometries with SO(4)/${\mathbb Z}_k$
$\times$SO(4)/${\mathbb Z}_k$ isometry, in the large $N$ limit. Our analysis is
based on the evaluation of vacuum expectation values of chiral primary
operators from the supersymmetric vacua of mass-deformed ABJM theory and from
the implementation of Kaluza-Klein holography to the LLM geometries. We focus
on the chiral primary operator with conformal dimension $\Delta = 1$. We show
that $\langle {\cal O}^{(\Delta=1)}\rangle= N^{\frac32} \, f_{(\Delta=1)}$ for
all supersymmetric vacuum solutions and LLM geometries with $k=1$, where the
factor $f_{(\Delta)}$ is independent of $N$. We also confirm that the vacuum
expectation value of the the energy momentum tensor is vanishing as expected by
the supersymmetry. We extend our results to the case of $k\ne 1$ for LLM
geometries represented by rectangular-shaped Young-diagrams. In analogy with
the Coulomb branch of the ${\cal N} = 4$ super Yang-Mills theory, we argue that
the discrete Higgs vacua of the mABJM theory as well as the corresponding LLM
geometries are parametrized by the vevs of the chiral primary operators.Comment: 44 pages, 1 figure, major corrections in section 3 and 5, references
added, title change

### Deceiving Google's Cloud Video Intelligence API Built for Summarizing Videos

Despite the rapid progress of the techniques for image classification, video
annotation has remained a challenging task. Automated video annotation would be
a breakthrough technology, enabling users to search within the videos.
Recently, Google introduced the Cloud Video Intelligence API for video
analysis. As per the website, the system can be used to "separate signal from
noise, by retrieving relevant information at the video, shot or per frame"
level. A demonstration website has been also launched, which allows anyone to
select a video for annotation. The API then detects the video labels (objects
within the video) as well as shot labels (description of the video events over
time). In this paper, we examine the usability of the Google's Cloud Video
Intelligence API in adversarial environments. In particular, we investigate
whether an adversary can subtly manipulate a video in such a way that the API
will return only the adversary-desired labels. For this, we select an image,
which is different from the video content, and insert it, periodically and at a
very low rate, into the video. We found that if we insert one image every two
seconds, the API is deceived into annotating the video as if it only contained
the inserted image. Note that the modification to the video is hardly
noticeable as, for instance, for a typical frame rate of 25, we insert only one
image per 50 video frames. We also found that, by inserting one image per
second, all the shot labels returned by the API are related to the inserted
image. We perform the experiments on the sample videos provided by the API
demonstration website and show that our attack is successful with different
videos and images

### Strong pinning of vortices by antiferromagnetic domain boundaries in CeCo(In$_{1-x}$Cd$_x$)$_5$

We have studied the isothermal magnetization $M(H)$ of
CeCo(In$_{1-x}$Cd$_x$)$_5$ with $x$ = 0.0075 and 0.01 down to 50 mK. Pronounced
field-history dependent phenomena occur in the coexistence regime of the
superconducting and antiferromagnetic phases. At low-fields, a phenomenological
model of magnetic-flux entry well explains $M(H)$ implying the dominance of
bulk pinning effect. However, unless crystallographic quenched disorder is
hysteretic, the asymmetric peak effect (ASPE) which appears at higher fields
cannot be explained by the pinning of vortices due to material defects. Also
the temperature dependence of the ASPE deviates from the conventional scenario
for the peak effect. Comparison of our thermodynamic phase diagrams with those
from previous neutron scattering and magnetoresistance experiments indicates
that the pinning of vortices takes place at the field-history dependent
antiferromagnetic domain boundaries.Comment: 13 pages,4 figures, to be published in New Journal of Physic

### Radiative Transfer on Perturbations in Protoplanetary Disks

We present a method for calculating the radiative tranfer on a protoplanetary
disk perturbed by a protoplanet. We apply this method to determine the effect
on the temperature structure within the photosphere of a passive circumstellar
disk in the vicinity of a small protoplanet of up to 20 Earth masses. The
gravitational potential of a protoplanet induces a compression of the disk
material near it, resulting in a decrement in the density at the disk's
surface. Thus, an isodensity contour at the height of the photosphere takes on
the shape of a well. When such a well is illuminated by stellar irradiation at
grazing incidence, it results in cooling in a shadowed region and heating in an
exposed region. For typical stellar and disk parameters relevant to the epoch
of planet formation, we find that the temperature variation due to a
protoplanet at 1 AU separation from its parent star is about 4% (5 K) for a
planet of 1 Earth mass, about 14% (19 K) for planet of 10 Earth masses, and
about 18% (25 K) for planet of 20 Earth masses, We conclude that even such
relatively small protoplanets can induce temperature variations in a passive
disk. Therefore, many of the processes involved in planet formation should not
be modeled with a locally isothermal equation of state.Comment: 23 pages, 8 figures (including 3 color figs). Submitted to Ap

### Pressure effects on the heavy-fermion antiferromagnet CeAuSb2

The f-electron compound CeAuSb2, which crystallizes in the ZrCuSi2-type
tetragonal structure, orders antiferromagnetically between 5 and 6.8 K, where
the antiferromagnetic transition temperature T_N depends on the occupancy of
the Au site. Here we report the electrical resistivity and heat capacity of a
high-quality crystal CeAuSb2 with T_N of 6.8 K, the highest for this compound.
The magnetic transition temperature is initially suppressed with pressure, but
is intercepted by a new magnetic state above 2.1 GPa. The new phase shows a
dome shape with pressure and coexists with another phase at pressures higher
than 4.7 GPa. The electrical resistivity shows a T^2 Fermi liquids behavior in
the complex magnetic state, and the residual resistivity and the T^2
resistivity coefficient increases with pressure, suggesting the possibility of
a magnetic quantum critical point at a higher pressure.Comment: 5 pages, 5 firure

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