521 research outputs found
On the "Universal" N=2 Supersymmetry of Classical Mechanics
In this paper we continue the study of the geometrical features of a
functional approach to classical mechanics proposed some time ago. In
particular we try to shed some light on a N=2 "universal" supersymmetry which
seems to have an interesting interplay with the concept of ergodicity of the
system. To study the geometry better we make this susy local and clarify
pedagogically several issues present in the literature. Secondly, in order to
prepare the ground for a better understanding of its relation to ergodicity, we
study the system on constant energy surfaces. We find that the procedure of
constraining the system on these surfaces injects in it some local grassmannian
invariances and reduces the N=2 global susy to an N=1.Comment: few misprints fixed with respect to Int.Jour.Mod.Phys.A vol 16, no15
(2001) 270
A Simple Algebraic Derivation of the Covariant Anomaly and Schwinger Term
An expression for the curvature of the "covariant" determinant line bundle is
given in even dimensional space-time. The usefulness is guaranteed by its
prediction of the covariant anomaly and Schwinger term. It allows a parallel
derivation of the consistent anomaly and Schwinger term, and their covariant
counterparts, which clarifies the similarities and differences between them. In
particular, it becomes clear that in contrary to the case for anomalies, the
difference between the consistent and covariant Schwinger term can not be
extended to a local form on the space of gauge potentials.Comment: 16 page
Gravitational Instantons from Gauge Theory
A gauge theory can be formulated on a noncommutative (NC) spacetime. This NC
gauge theory has an equivalent dual description through the so-called
Seiberg-Witten (SW) map in terms of an ordinary gauge theory on a commutative
spacetime. We show that all NC U(1) instantons of Nekrasov-Schwarz type are
mapped to ALE gravitational instantons by the exact SW map and that the NC
gauge theory of U(1) instantons is equivalent to the theory of hyper-Kaehler
geometries. It implies the remarkable consequence that ALE gravitational
instantons can emerge from local condensates of purely NC photons.Comment: 4 pages with two columns; comments and references added, to appear in
Phys. Rev. Let
Heterotic T-Duality and the Renormalization Group
We consider target space duality transformations for heterotic sigma models
and strings away from renormalization group fixed points. By imposing certain
consistency requirements between the T-duality symmetry and renormalization
group flows, the one loop gauge beta function is uniquely determined, without
any diagram calculations. Classical T-duality symmetry is a valid quantum
symmetry of the heterotic sigma model, severely constraining its
renormalization flows at this one loop order. The issue of heterotic anomalies
and their cancelation is addressed from this duality constraining viewpoint.Comment: 17 pages, Late
Path-Integral Quantization of the (2,2) String
A complete treatment of the (2,2) NSR string in flat (2+2) dimensional
space-time is given, from the formal path integral over N=2 super Riemann
surfaces to the computational recipe for amplitudes at any loop or gauge
instanton number. We perform in detail the superconformal gauge fixing, discuss
the spectral flow, and analyze the supermoduli space with emphasis on the gauge
moduli. Background gauge field configurations in all instanton sectors are
constructed. We develop chiral bosonization on punctured higher-genus surfaces
in the presence of gauge moduli and instantons. The BRST cohomology is
recapitulated, with a new space-time interpretation for picture-changing. We
point out two ways of combining left- and right-movers, which lead to different
three-point functions.Comment: 36 pages, LaTeX; published version (typos & eq.(7.12) corrected
Massive Hyper-Kahler Sigma Models and BPS Domain Walls
With the non-Abelian Hyper-Kahler quotient by U(M) and SU(M) gauge groups, we
give the massive Hyper-Kahler sigma models that are not toric in the N=1
superfield formalism. The U(M) quotient gives N!/[M! (N-M)!] (N is a number of
flavors) discrete vacua that may allow various types of domain walls, whereas
the SU(M) quotient gives no discrete vacua. We derive BPS domain wall solution
in the case of N=2 and M=1 in the U(M) quotient model.Comment: 16 pages, 1 figure, contribution to the Proceedings of the
International Conference on "Symmetry Methods in Physics (SYM-PHYS10)" held
at Yerevan, Armenia, 13-19 Aug. 200
A cosmotopological relation for a unified field theory
I present an argument, based on the topology of the universe, why there are
three generations of fermions. The argument implies a preferred unified gauge
group of SU(5), but with SO(10) representations of the fermions. The breaking
pattern is preferred over the
pattern . On the basis of the argument one expects
an asymmetry in the microwave data, which might have been detected already.Comment: 6 page
Non-linear Vacuum Phenomena in Non-commutative QED
We show that the classic results of Schwinger on the exact propagation of
particles in the background of constant field-strengths and plane waves can be
readily extended to the case of non-commutative QED. It is shown that
non-perturbative effects on constant backgrounds are the same as their
commutative counterparts, provided the on-shell gauge invariant dynamics is
referred to a non-perturbatively related space-time frame. For the case of the
plane wave background, we find evidence of the effective extended nature of
non-commutative particles, producing retarded and advanced effects in
scattering. Besides the known `dipolar' character of non-commutative neutral
particles, we find that charged particles are also effectively extended, but
they behave instead as `half-dipoles'.Comment: LaTeX, 23 p
Comments on Supersymmetric Vector and Matrix Models
Some results in random matrices are generalized to supermatrices, in
particular supermatrix integration is reduced to an integration over the
eigenvalues and the resulting volume element is shown to be equivalent to a one
dimensional Coulomb gas of both positive and negative charges.It is shown
that,for polynomial potentials, after removing the instability due to the
annihilation of opposite charges, supermatrix models are indistinguishable from
ordinary matrix models, in agreement with a recent result by Alvarez-Gaume and
Manes. It is pointed out however that this may not be true for more general
potentials such as for instance the supersymmetric generalization of the Penner
model.Comment: 6 page
Some Correlation Functions of Minimal Superconformal Models Coupled to Supergravity
We compute general three-point functions of minimal superconformal models
coupled to supergravity in the Neveu-Schwarz sector for spherical topology thus
extending to the superconformal case the results of Goulian and Li and of
Dotsenko.Comment: 15 page
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