23,426 research outputs found

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

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    The duality between a dd-dimensional conformal field theory with relevant deformation and a gravity theory on an asymptotically AdSd+1_{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 AdS4_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 AdS4_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

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    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 UL(N)×_{\textrm{L}}(N)\timesUR(N)_{\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

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    We test the holographic relation between the vacuum expectation values of gauge invariant operators in N=6{\cal N} = 6 Uk(N)×Uk(N){\rm U}_k(N)\times {\rm U}_{-k}(N) mass-deformed ABJM theory and the LLM geometries with Zk\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 Δ=1\Delta = 1, which is given by O(Δ=1)=N32f(Δ=1)\langle {\cal O}^{(\Delta=1)}\rangle= N^{\frac32} \, f_{(\Delta=1)}, for large NN and k=1k=1. Here factor f(Δ)f_{(\Delta)} is independent of NN. 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 k1k\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

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    We present a detailed account and extension of our claim in arXiv:1610.01490. We test the gauge/gravity duality between the N=6{\cal N} = 6 mass-deformed ABJM theory with Uk(N)×_k(N)\timesUk(N)_{-k}(N) gauge symmetry and the 11-dimensional supergravity on LLM geometries with SO(4)/Zk{\mathbb Z}_k ×\timesSO(4)/Zk{\mathbb Z}_k isometry, in the large NN 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 Δ=1\Delta = 1. We show that O(Δ=1)=N32f(Δ=1)\langle {\cal O}^{(\Delta=1)}\rangle= N^{\frac32} \, f_{(\Delta=1)} for all supersymmetric vacuum solutions and LLM geometries with k=1k=1, where the factor f(Δ)f_{(\Delta)} is independent of NN. 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 k1k\ne 1 for LLM geometries represented by rectangular-shaped Young-diagrams. In analogy with the Coulomb branch of the N=4{\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

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    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(In1x_{1-x}Cdx_x)5_5

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    We have studied the isothermal magnetization M(H)M(H) of CeCo(In1x_{1-x}Cdx_x)5_5 with xx = 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)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

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    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

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    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