341 research outputs found
Инновационные методы в области управления персоналом
Целью статьи является обоснование инновационных методов в области управления персоналом
Vacuum polarization by a global monopole with finite core
We investigate the effects of a -dimensional global monopole core on
the behavior of a quantum massive scalar field with general curvature coupling
parameter. In the general case of the spherically symmetric static core,
formulae are derived for the Wightman function, for the vacuum expectation
values of the field square and the energy-momentum tensor in the exterior
region. These expectation values are presented as the sum of point-like global
monopole part and the core induced one. The asymptotic behavior of the core
induced vacuum densities is investigated at large distances from the core, near
the core and for small values of the solid angle corresponding to strong
gravitational fields. In particular, in the latter case we show that the
behavior of the vacuum densities is drastically different for minimally and
non-minimally coupled fields. As an application of general results the
flower-pot model for the monopole's core is considered and the expectation
values inside the core are evaluated.Comment: 22 pages, 4 figures, misprint is corrected, discussion is added,
figures are change
Non-holomorphic multi-matrix gauge invariant operators based on Brauer algebra
We present an orthogonal basis of gauge invariant operators constructed from
some complex matrices for the free matrix field, where operators are expressed
with the help of Brauer algebra. This is a generalisation of our previous work
for a signle complex matrix. We also discuss the matrix quantum mechanics
relevant to N=4 SYM on S^{3} times R. A commuting set of conserved operators
whose eigenstates are given by the orthogonal basis is shown by using enhanced
symmetries at zero coupling.Comment: 29 pages, typos corrected, references adde
Single parameter scaling in 1-D localized absorbing systems
Numerical study of the scaling of transmission fluctuations in the 1-D
localization problem in the presence of absorption is carried out. Violations
of single parameter scaling for lossy systems are found and explained on the
basis of a new criterion for different types of scaling behavior derived by
Deych et al [Phys. Rev. Lett., {\bf 84}, 2678 (2000)].Comment: 7 pages, 6 figures, RevTex, submitted to Phys. Rev.
Wightman function and vacuum densities for a Z_2-symmetric thick brane in AdS spacetime
Positive frequency Wightman function, vacuum expectation values of the field
square and the energy-momentum tensor induced by a Z_{2}-symmetric brane with
finite thickness located on (D+1)- dimensional AdS background are evaluated for
a massive scalar field with general curvature coupling parameter. For the
general case of static plane symmetric interior structure the expectation
values in the region outside the brane are presented as the sum of free AdS and
brane induced parts. For a conformally coupled massless scalar the brane
induced part in the vacuum energy-momentum tensor vanishes. In the limit of
strong gravitational fields the brane induced parts are exponentially
suppressed for points not too close to the brane boundary. As an application of
general results a special model is considered in which the geometry inside the
brane is a slice of the Minkowski spacetime orbifolded along the direction
perpendicular to the brane. For this model the Wightman function, vacuum
expectation values of the field square and the energy-momentum tensor inside
the brane are evaluated as well and their behavior is discussed in various
asymptotic regions of the parameters. It is shown that for both minimally and
conformally coupled scalar fields the interior vacuum forces acting on the
brane boundaries tend to decrease the brane thickness.Comment: 25 pages, 6 figures, discussion adde
Upper critical field calculations for the high critical temperature superconductors considering inhomogeneities
We perform calculations to obtain the curve of high temperature
superconductors (HTSC). We consider explicitly the fact that the HTSC possess
intrinsic inhomogeneities by taking into account a non uniform charge density
. The transition to a coherent superconducting phase at a critical
temperature corresponds to a percolation threshold among different
superconducting regions, each one characterized by a given .
Within this model we calculate the upper critical field by means of an
average linearized Ginzburg-Landau (GL) equation to take into account the
distribution of local superconducting temperatures . This
approach explains some of the anomalies associated with and why
several properties like the Meissner and Nernst effects are detected at
temperatures much higher than .Comment: Latex text, add reference
Fluctuating Fuzzy Funnels
It is well known that a D-string ending on a D3, D5 or D7 brane is described
in terms of a non-commutative fuzzy funnel geometry. In this article, we give a
numerical study of the fluctuations about this leading geometry. This allows us
to investigate issues related to the stability and moduli space of these
solutions. We comment on the comparison to the linearized fluctuations in
supergravity.Comment: 24 pages, 3 figures; v2 references added and correcte
BPS Operators in N=4 SYM: Calogero Models and 2D Fermions
A connection between the gauge fixed dynamics of protected operators in
superconformal Yang-Mills theory in four dimensions and Calogero systems is
established. This connection generalizes the free Fermion description of the
chiral primary operators of the gauge theory formed out of a single complex
scalar to more general operators. In particular, a detailed analysis of
protected operators charged under an su(1|1)contained in psu(2,2|4) is carried
out and a class of operators is identified, whose dynamics is described by the
rational super-Calogero model. These results are generalized to arbitrary BPS
operators charged under an su(2|3) of the superconformal algebra. Analysis of
the non-local symmetries of the super-Calogero model is also carried out, and
it is shown that symmetry for a large class of protected operators is a
contraction of the corresponding Yangian algebra to a loop algebra.Comment: 29 pages, 3 figure
Repulsive Casimir-Polder forces from cosmic strings
We investigate the Casimir-Polder force acting on a polarizable microparticle
in the geometry of a straight cosmic string. In order to develop this analysis
we evaluate the electromagnetic field Green tensor on the imaginary frequency
axis. The expression for the Casimir-Polder force is derived in the general
case of anisotropic polarizability. In dependence of the eigenvalues for the
polarizability tensor and of the orientation of its principal axes, the
Casimir-Polder force can be either repulsive or attractive. Moreover, there are
situations where the force changes the sign with separation. We show that for
an isotropic polarizability tensor the force is always repulsive. At large
separations between the microparticle and the string, the force varies
inversely as the fifth power of the distance. In the non-retarded regime,
corresponding to separations smaller than the relevant transition wavelengths,
the force decays as the inverse fourth power of the distance. In the case of
anisotropic polarizability, the dependence of the Casimir-Polder potential on
the orientation of the polarizability tensor principal axes also leads to the
moment of force acting on the particle.Comment: 16 pages, 2 figure
Effects of type of physical exercise and leisure activities on the depression scores of obese Brazilian adolescent girls
- …