25,065 research outputs found
Frozen ghosts in thermal gauge field theory
We review an alternative formulation of gauge field theories at finite
temperature where unphysical degrees of freedom of gauge fields and the
Faddeev-Popov ghosts are kept at zero temperature.Comment: 6 page
A Popov Stability Condition for Uncertain Linear Quantum Systems
This paper considers a Popov type approach to the problem of robust stability
for a class of uncertain linear quantum systems subject to unknown
perturbations in the system Hamiltonian. A general stability result is given
for a general class of perturbations to the system Hamiltonian. Then, the
special case of a nominal linear quantum system is considered with quadratic
perturbations to the system Hamiltonian. In this case, a robust stability
condition is given in terms of a frequency domain condition which is of the
same form as the standard Popov stability condition.Comment: A shortened version to appear in the proceedings of the 2013 American
Control Conferenc
Researching of properties of expanded clay concrete on cement-ash binder.
Ukraine is a state with a powerful industrial base,the waste of which is ash. The use of ash as a binder for the production of expanded clay concrete solves the problem of its disposal. Studies of expanded clay concrete on carbonates and and cement-ash binder were carried out.The research results showed that it is possible to manufacture building structures from this material, including load-bearing ones. Experiments have confirmed the effectiveness of using a cement-ash binder [Vilkov, 1984]. The article provides recommendations on the technology of production of expanded clay concrete mixture and determination of optimal composition. Were made and tested samples of expanded clay concrete on a cement-ash binder with varying degrees of reinforcement with dimensions of 100x150x1200mm. The bearing capacity, crack resistance and deformability of expanded clay concrete were determined by testing on hydraulic press. The compressive strength of the studied expanded clay concrete was tested by loading samples with dimensions of 10x10x10cm and 10x10x40cm. The perspectives of using expanded clay concrete on a cement- ash binder are analyzed.
Keywords: expanded clay concrete, industrial waste, binding material, ash, carbonate send, strength, deflection, deformation, building construction
Ab initio methods for finite temperature two-dimensional Bose gases
The stochastic Gross-Pitaevskii equation and modified Popov theory are shown
to provide an ab initio description of finite temperature, weakly-interacting
two-dimensional Bose gas experiments. Using modified Popov theory, a systematic
approach is developed in which the momentum cut-off inherent to classical field
methods is removed as a free parameter. This is shown to yield excellent
agreement with the recent experiment of Hung et al. [Nature, 470, 236 (2011)],
verifying that the stochastic Gross-Pitaevskii equation captures the observed
universality and scale-invariance.Comment: 5 pages, 4 figure
The influence of Gribov copies on the gluon and ghost propagator
The dependence of the gluon and ghost propagator in pure SU(3) gauge theory
on the choice of Gribov copies in Landau gauge is studied. Simulations were
performed on several lattice sizes at =5.8, 6.0 and 6.2. In the infrared
region the ghost propagator turns out to depend on the choice, while the impact
on the gluon propagator is not resolvable. Also the eigenvalue distribution of
the Faddeev-Popov operator is sensitive to Gribov copies.Comment: Talk presented at Quark Confinement and the Hadron Spectrum VI,
Villasimius, Sardinia, Italy, September 21-25, 2004, 3 pages, 2 figure
Global unitary fixing and matrix-valued correlations in matrix models
We consider the partition function for a matrix model with a global unitary
invariant energy function. We show that the averages over the partition
function of global unitary invariant trace polynomials of the matrix variables
are the same when calculated with any choice of a global unitary fixing, while
averages of such polynomials without a trace define matrix-valued correlation
functions, that depend on the choice of unitary fixing. The unitary fixing is
formulated within the standard Faddeev-Popov framework, in which the squared
Vandermonde determinant emerges as a factor of the complete Faddeev-Popov
determinant. We give the ghost representation for the FP determinant, and the
corresponding BRST invariance of the unitary-fixed partition function. The
formalism is relevant for deriving Ward identities obeyed by matrix-valued
correlation functions.Comment: Tex, 22 page
Study of narrow baryon resonance decaying into in -interactions at with SVD-2
The inclusive reaction was studied at IHEP accelerator
with proton beam using SVD-2 detector. Two different samples of
, statistically independent and belonging to different phase space
regions were used in the analyses and a narrow baryon resonance with the mass
was observed in both samples of the
dataComment: 3 pages, 6 figures, to be published in the Proceedings of the XXXIII
International Conference of High Energy Physics (ICHEP'06), Moscow, 200
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