7,316 research outputs found
N=1 SYM Action and BRST Cohomology
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
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
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 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
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
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
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AdS_3 Partition Functions Reconstructed
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
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
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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