43 research outputs found
A reparametrization invariant surface ordering
We introduce a notion of a non-Abelian loop gauge field defined on points in
loop space. For this purpose we first find an infinite-dimensional tensor
product representation of the Lie algebra which is particularly suited for
fields on loop space. We define the non-Abelian Wilson surface as a `time'
ordered exponential in terms of this loop gauge field and show that it is
reparametrization invariant.Comment: 11 pages, clarifications and added ref
Інтродукція мандрагори туркменської в умовах ботанічного саду АН Республіки Узбекистан
Bioecological peculiarities of Mandragora turcomanica O.F. Mizgir have been studied; optimal term of seeding has been determined, phenological and generative phases of development have been found out.Вивчено біоекологічні особливості мандрагори туркменської, визначено оптимальний термін сівби, виявлено фенологічні та генеративні фази розвитку
Comparative study of loop contributions in AdS and dS
The generic feature of non-conformal fields in Poincare patch of de Sitter
space is the presence of large IR loop corrections even for massive fields.
Moreover, in global de Sitter there are loop IR divergences for the massive
fields. Naive analytic continuation from de Sitter to Anti-de-Sitter might lead
one to conclude that something similar should happen in the latter space as
well. However, we show that there are no large IR effects in the one-loop
two-point functions in the Poincare patch of Anti-de-Sitter space even for the
zero mass minimally coupled scalar fields. As well there are neither large IR
effects nor IR divergences in global Anti-de-Sitter space even for the zero
mass.Comment: 12 pages. Minor changes, misprints are correcte
Born--Oppenheimer corrections to the effective zero-mode Hamiltonian in SYM theory
We calculate the subleading terms in the Born--Oppenheimer expansion for the
effective zero-mode Hamiltonian of N = 1, d=4 supersymmetric Yang--Mills theory
with any gauge group. The Hamiltonian depends on 3r abelian gauge potentials
A_i, lying in the Cartan subalgebra, and their superpartners (r being the rank
of the group). The Hamiltonian belongs to the class of N = 2 supersymmetric QM
Hamiltonia constructed earlier by Ivanov and I. Its bosonic part describes the
motion over the 3r--dimensional manifold with a special metric. The corrections
explode when the root forms \alpha_j(A_i) vanish and the Born--Oppenheimer
approximation breaks down.Comment: typos correcte
D-brane annihilation, renormalization-group flow and non-linear -model for the ADHM construction
In this note - and anti--brane annihilation in type I string theory
is probed by a -brane. We consider the covariant Green-Schwarz or twistor
formulation of the probe theory. We expect the theory to be -invariant
after the annihilation is completed. Conditions of the -invariance of
the theory impose constraints on the background tachyon field. Solutions to the
constraints define tachyon values which correspond to type I -branes as
remnants of the annihilation. As a byproduct we get a theory which lies in the
same universality class as the non-linear -model for the
Atiyah-Drinfeld-Hitchin-Manin construction.Comment: 11pages, Latex, Language of the text is considerably improve
"Charged" Particle's Tunneling from Rotating Black Holes
The behavior of a scalar field theory near the event horizon in a rotating
black hole background can be effectively described by a two dimensional field
theory in a gauge field background. Based on this fact, we proposal that the
quantum tunneling from rotating black hole can be treated as "charged"
particle' s tunneling process in its effectively two dimensional metric. Using
this viewpoint and considering the corresponding "gauge charge" conservation,
we calculate the non-thermal tunneling rate of Kerr black hole and Myers-Perry
black hole, and results are consistent with Parikh-Wilczek's original result
for spherically symmetric black holes. Especially for Myers-Perry black hole
which has multi-rotation parameters, our calculation fills in the gap existing
in the literature applying Parikh-Wilczek's tunneling method to various types
black holes. Our derivation further illuminates the essential role of effective
gauge symmetry in Hawking radiation from rotating black holes.Comment: 15 pages, no figure; any comments are welcome
The Boundary State Formalism and Conformal Invariance in Off-shell String Theory
We present a generalization of the boundary state formalism for the bosonic
string that allows us to calculate the overlap of the boundary state with
arbitrary closed string states. We show that this generalization exactly
reproduces world-sheet sigma model calculations, thus giving the correct
overlap with both on- and off-shell string states, and that this new boundary
state automatically satisfies the requirement for integrated vertex operators
in the case of non-conformally invariant boundary interactions.Comment: 19 pages, 0 figure
Towards the String representation of the dual Abelian Higgs model beyond the London limit
We perform a path-integral analysis of the string representation of the dual
Abelian Higgs (DAH) model beyond the London limit, where the string describing
the vortex of a flux tube has a finite thickness. We show that besides an
additional vortex core contribution to the string tension, a modified Yukawa
interaction appears as a boundary contribution in the type-II dual
superconducting vacuum. In the London limit, the modified Yukawa interaction is
reduced to the Yukawa one.Comment: 13 pages, JHEP3.cls is used, no figures. The version accepted for
publication in JHE
One-loop Beta Functions for the Orientable Non-commutative Gross-Neveu Model
We compute at the one-loop order the beta-functions for a renormalisable
non-commutative analog of the Gross Neveu model defined on the Moyal plane. The
calculation is performed within the so called x-space formalism. We find that
this non-commutative field theory exhibits asymptotic freedom for any number of
colors. The beta-function for the non-commutative counterpart of the Thirring
model is found to be non vanishing.Comment: 16 pages, 9 figure
Breakdown of Semiclassical Methods in de Sitter Space
Massless interacting scalar fields in de Sitter space have long been known to
experience large fluctuations over length scales larger than Hubble distances.
A similar situation arises in condensed matter physics in the vicinity of a
critical point, and in this better-understood situation these large
fluctuations indicate the failure in this regime of mean-field methods. We
argue that for non-Goldstone scalars in de Sitter space, these fluctuations can
also be interpreted as signaling the complete breakdown of the semi-classical
methods widely used throughout cosmology. By power-counting the infrared
properties of Feynman graphs in de Sitter space we find that for a massive
scalar interacting through a \lambda \phi^4$ interaction, control over the loop
approximation is lost for masses smaller than m \simeq \sqrt \lambda H/2\pi,
where H is the Hubble scale. We briefly discuss some potential implications for
inflationary cosmology.Comment: 24 pages, 7 figures, v2; added references, clarified the resummation
discussio