7,316 research outputs found

    N=1 SYM Action and BRST Cohomology

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    The relation between BRST cohomology and the N=1 supersymmetric Yang-Mills action in 4 dimensions is discussed. In particular, it is shown that both off and on shell N=1 SYM actions are related to a lower dimensional field polynomial by solving the descent equations, which is obtained from the cohomological analysis of linearized Slavnov-Taylor operator \B, in the framework of Algebraic Renormalization. Furthermore we show that off and on shell solutions differ only by a \B- exact term, which is a consequence of the fact that the cohomology of both cases are same.Comment: 14 Pages, LaTex. Revised version. To be published in MPL

    Softly broken supersymmetric Yang-Mills theories: Renormalization and non-renormalization theorems

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    We present a minimal version for the renormalization of softly broken Super-Yang-Mills theories using the extended model with a local gauge coupling. It is shown that the non-renormalization theorems of the case with unbroken supersymmetry are valid without modifications and that the renormalization of soft-breaking parameters is completely governed by the renormalization of the supersymmetric parameters. The symmetry identities in the present context are peculiar, since the extended model contains two anomalies: the Adler-Bardeen anomaly of the axial current and an anomaly of supersymmetry in the presence of the local gauge coupling. From the anomalous symmetries we derive the exact all-order expressions for the beta functions of the gauge coupling and of the soft-breaking parameters. They generalize earlier results to arbitrary normalization conditions and imply the NSVZ expressions for a specific normalization condition on the coupling.Comment: 24 pages, LaTeX, v2: one reference adde

    F-GAMMA: Multi-frequency radio monitoring of Fermi blazars. The 2.64 to 43 GHz Effelsberg light curves from 2007-2015

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    The advent of the Fermi-GST with its unprecedented capability to monitor the entire 4 pi sky within less than 2-3 hours, introduced new standard in time domain gamma-ray astronomy. To explore this new avenue of extragalactic physics the F-GAMMA programme undertook the task of conducting nearly monthly, broadband radio monitoring of selected blazars from January 2007 to January 2015. In this work we release all the light curves at 2.64, 4.85, 8.35, 10.45, 14.6, 23.05, 32, and 43 GHz and present first order derivative data products after all necessary post-measurement corrections and quality checks; that is flux density moments and spectral indices. The release includes 155 sources. The effective cadence after the quality flagging is around one radio SED every 1.3 months. The coherence of each radio SED is around 40 minutes. The released dataset includes more than 4×1044\times10^4 measurements. The median fractional error at the lowest frequencies (2.64-10.45 GHz) is below 2%. At the highest frequencies (14.6-43 GHz) with limiting factor of the atmospheric conditions, the errors range from 3% to 9%, respectively.Comment: Accepted for publication in Section: Catalogs and data of Astronomy & Astrophysic

    Study of the conditions of fracture at explosive compaction of powders

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    Joint theoretical and experimental investigations have allowed to realize an approach with use of mathematical and physical modeling of processes of a shock wave loading of powder materials.In order to gain a better insight into the effect of loading conditions and, in particular, to study the effect of detonation velocity, explosive thickness, and explosion pressure on the properties of the final sample, we numerically solved the problem about powder compaction in the axisymmetric case.The performed analysis shows that an increase in the decay time of the pressure applied to the sample due to an increase of the explosive thickness or the external loading causes no shrinkage of the destructed region at a fixed propagation velocity of the detonation wave. Simultaneously, a decrease in the propagation velocity of the detonation wave results in an appreciable shrinkage of this region

    Quantum Channels with Memory

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    We present a general model for quantum channels with memory, and show that it is sufficiently general to encompass all causal automata: any quantum process in which outputs up to some time t do not depend on inputs at times t' > t can be decomposed into a concatenated memory channel. We then examine and present different physical setups in which channels with memory may be operated for the transfer of (private) classical and quantum information. These include setups in which either the receiver or a malicious third party have control of the initializing memory. We introduce classical and quantum channel capacities for these settings, and give several examples to show that they may or may not coincide. Entropic upper bounds on the various channel capacities are given. For forgetful quantum channels, in which the effect of the initializing memory dies out as time increases, coding theorems are presented to show that these bounds may be saturated. Forgetful quantum channels are shown to be open and dense in the set of quantum memory channels.Comment: 21 pages with 5 EPS figures. V2: Presentation clarified, references adde

    AdS_3 Partition Functions Reconstructed

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    For pure gravity in AdS_3, Witten has given a recipe for the construction of holomorphically factorizable partition functions of pure gravity theories with central charge c=24k. The partition function was found to be a polynomial in the modular invariant j-function. We show that the partition function can be obtained instead as a modular sum which has a more physical interpretation as a sum over geometries. We express both the j-function and its derivative in terms of such a sum.Comment: 9 page

    Bilayer Membrane in Confined Geometry: Interlayer Slide and Steric Repulsion

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    We derived free energy functional of a bilayer lipid membrane from the first principles of elasticity theory. The model explicitly includes position-dependent mutual slide of monolayers and bending deformation. Our free energy functional of liquid-crystalline membrane allows for incompressibility of the membrane and vanishing of the in-plane shear modulus and obeys reflectional and rotational symmetries of the flat bilayer. Interlayer slide at the mid-plane of the membrane results in local difference of surface densities of the monolayers. The slide amplitude directly enters free energy via the strain tensor. For small bending deformations the ratio between bending modulus and area compression coefficient, Kb/KA, is proportional to the square of monolayer thickness, h. Using the functional we performed self-consistent calculation of steric potential acting on bilayer between parallel confining walls separated by distance 2d. We found that temperature-dependent curvature at the minimum of confining potential is enhanced four times for a bilayer with slide as compared with a unit bilayer. We also calculate viscous modes of bilayer membrane between confining walls. Pure bending of the membrane is investigated, which is decoupled from area dilation at small amplitudes. Three sources of viscous dissipation are considered: water and membrane viscosities and interlayer drag. Dispersion has two branches. Confinement between the walls modifies the bending mode with respect to membrane in bulk solution. Simultaneously, inter-layer slipping mode, damped by viscous drag, remains unchanged by confinement.Comment: 23 pages,3 figures, pd

    Holographic Coulomb branch vevs

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    We compute holographically the vevs of all chiral primary operators for supergravity solutions corresponding to the Coulomb branch of N=4 SYM and find exact agreement with the corresponding field theory computation. Using the dictionary between 10d geometries and field theory developed to extract these vevs, we propose a gravity dual of a half supersymmetric deformation of N=4 SYM by certain irrelevant operators.Comment: 16 pages, v2 corrections in appendi
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