3,719 research outputs found
Five-dimensional Monopole Equation with Hedge-Hog Ansatz and Abel's Differential Equation
We review the generalized monopole in the five-dimensional Euclidean space. A
numerical solution with the Hedge-Hog ansatz is studied. The Bogomol'nyi
equation becomes a second order autonomous non-linear differential equation.
The equation can be translated into the Abel's differential equation of the
second kind and is an algebraic differential equation.Comment: 4 pages, 4 figures, typos correcte
Conformal Moduli and b-c Pictures for NSR Strings
We explore the geometry of the superconformal moduli of the NSR superstring
theory in order to construct the consistent sigma-model for the NSR strings,
free of picture-changing ambiguities. The sigma-model generating functional is
constructed by the integration over the bosonic and anticommuting moduli,
corresponding to insertions of the vertex operators in scattering amplitudes.
In particular, the integration over the bosonic moduli results in the
appearance of picture-changing operators for the b-c system. Important example
of the b-c pictures involves the unintegrated and integrated forms of the
vertex operators. We derive the BRST-invariant expressions for the b-c
picture-changing operators for open and closed strings and study some of their
properties. We also show that the superconformal moduli spaces of the NSR
superstring theory contain the global singularities, leading to the appearance
of non-perturbative solitonic D-brane creation operators.Comment: 22 pages, references adde
Non-Abelian Semilocal Strings in N=2 Supersymmetric QCD
We consider a benchmark bulk theory in four-dimensions: N=2 supersymmetric
QCD with the gauge group U(N) and N_f flavors of fundamental matter
hypermultiplets (quarks). The nature of the BPS strings in this benchmark
theory crucially depends on N_f. If N_f\geq N and all quark masses are equal,
it supports non-Abelian BPS strings which have internal (orientational) moduli.
If N_f>N these strings become semilocal, developing additional moduli \rho
related to (unlimited) variations of their transverse size.
Using the U(2) gauge group with N_f=3,4 as an example, we derive an effective
low-energy theory on the (two-dimensional) string world sheet. Our derivation
is field-theoretic, direct and explicit: we first analyze the Bogomol'nyi
equations for string-geometry solitons, suggest an ansatz and solve it at large
\rho. Then we use this solution to obtain the world-sheet theory.
In the semiclassical limit our result confirms the Hanany-Tong conjecture,
which rests on brane-based arguments, that the world-sheet theory is N=2
supersymmetric U(1) gauge theory with N positively and N_e=N_f-N negatively
charged matter multiplets and the Fayet-Iliopoulos term determined by the
four-dimensional coupling constant. We conclude that the Higgs branch of this
model is not lifted by quantum effects. As a result, such strings cannot
confine.
Our analysis of infrared effects, not seen in the Hanany-Tong consideration,
shows that, in fact, the derivative expansion can make sense only provided the
theory under consideration is regularized in the infrared, e.g. by the quark
mass differences. The world-sheet action discussed in this paper becomes a bona
fide low-energy effective action only if \Delta m_{AB}\neq 0.Comment: 36 pages, no figure
Magnetic strings in Lattice QCD as Nonabelian Vortices
Lattice studies indicate existence of magnetic strings in QCD vacuum. We
argue that recently found nonabelian strings with rich worldsheet dynamics
provide a proper pattern for the strings observed on the lattice. In
particular, within this pattern we explain the localization of the
monopole-antimonopole pairs on the magnetic string worldsheet and the negative
contribution of the magnetic strings into the vacuum energy and gluon
condensate. We suggest the D2 brane realization of the magnetic string which
explains the temperature dependence of its tension.Comment: 17 pages, 1 figur
On the issue of public-private partnership in housing construction in the Belgorod region
The article discusses the opportunities and prospects for the use of public-private partnership (PPP) tools for the implementation of investment projects in housing construction in the Belgorod region. The application of the PPP concept will allow to attract additional investment resources to the region, will provide an opportunity to strengthen its competitive advantages and unleash innovative potentia
Simplifying and Extending the AdS_5xS^5 Pure Spinor Formalism
Although the AdS_5xS^5 worldsheet action is not quadratic, some features of
the pure spinor formalism are simpler in an AdS_5xS^5 background than in a flat
background. The BRST operator acts geometrically, the left and right-moving
pure spinor ghosts can be treated as complex conjugates, the zero mode measure
factor is trivial, and the b ghost does not require non-minimal fields.
Furthermore, a topological version of the AdS_5xS^5 action with the same
worldsheet variables and BRST operator can be constructed by gauge-fixing a G/G
principal chiral model where G=PSU(2,2|4). This topological model is argued to
describe the zero radius limit that is dual to free N=4 super-Yang-Mills and
can also be interpreted as an "unbroken phase" of superstring theory.Comment: 39 pages harvma
Baxter Equation for the QCD Odderon
The Hamiltonian derived by Bartels, Kwiecinski and Praszalowicz for the study
of high-energy QCD in the generalized logarithmic approximation was found to
correspond to the Hamiltonian of an integrable spin chain. We study the
odderon Hamiltonian corresponding to three sites by means of the Bethe Ansatz
approach. We rewrite the Baxter equation, and consequently the Bethe Ansatz
equations, as a linear triangular system. We derive a new expression for the
eigenvectors and the eigenvalues, and discuss the quantization of the conserved
quantities.Comment: 14 pages, latex file, one figur
On the stability problem in the O(N) nonlinear sigma model
The stability problem for the O(N) nonlinear sigma model in the 2+\epsilon
dimensions is considered. We present the results of the 1/N^{2} order
calculations of the critical exponents (in the 2<d<4 dimensions) of the
composite operators relevant for this problem. The arguments in the favor of
the scenario with the conventional fixed point are given.Comment: 9 pages, revtex, 1 Postscript figur
Electromagnetic Interaction in the System of Multimonopoles and Vortex Rings
Behavior of static axially symmetric monopole-antimonopole and vortex ring
solutions of the SU(2) Yang-Mills-Higgs theory in an external uniform magnetic
field is considered. It is argued that the axially symmetric
monopole-antimonopole chains and vortex rings can be treated as a bounded
electromagnetic system of the magnetic charges and the electric current rings.
The magnitude of the external field is a parameter which may be used to test
the structure of the static potential of the effective electromagnetic
interaction between the monopoles with opposite orientation in the group space.
It is shown that for a non-BPS solutions there is a local minimum of this
potential.Comment: 10 pages, 12 figures, some minor corrections, version to appear in
Phys. Rev.
Compact QED3 with theta term and axionic confining strings
We discuss three dimensional compact QED with a theta term due to an axionic
field. The variational gauge invariant functional is considered and it is shown
that the ground state energy is independent of theta in a leading
approximation. The mass gap of the axionic field is found to be dependent upon
theta, the mass gap of the photon field and the scalar potential. The vacuum
expectation of the Wilson loop is shown to be independent of theta in a leading
approximation, to obey the area law and to lead to confinement. We also briefly
discuss the properties of axionic confining strings.Comment: 35 pages, LaTex, typing error correcte
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