6,286 research outputs found
New approach to nonlinear electrodynamics: dualities as symmetries of interaction
We elaborate on the duality-symmetric nonlinear electrodynamics in a new
formulation with auxiliary tensor fields. The Maxwell field strength appears
only in bilinear terms of the corresponding generic Lagrangian, while the
self-interaction is presented by a function E depending on the auxiliary
fields. Two types of dualities inherent in the nonlinear electrodynamics models
admit a simple off-shell characterization in terms of this function. In the
standard formulation, the continuous U(1) duality symmetry is nonlinearly
realized on the Maxwell field strength. In the new setting, the same symmetry
acts as linear U(1) transformations of the auxiliary field variables. The
nonlinear U(1) duality condition proves to be equivalent to the linear U(1)
invariance of the self-interaction E. The discrete self-duality (or
self-duality by Legendre transformation) amounts to a weaker reflection
symmetry of E. For a class of duality- symmetric Lagrangians we introduce an
alternative representation with the auxiliary scalar field and find new
explicit examples of such systems.Comment: Latex file, 21 page
Constitutive relations, off shell duality rotations and the hypergeometric form of Born-Infeld theory
We review equivalent formulations of nonlinear and higher derivatives
theories of electromagnetism exhibiting electric-magnetic duality rotations
symmetry. We study in particular on shell and off shell formulations of this
symmetry, at the level of action functionals as well as of equations of motion.
We prove the conjecture that the action functional leading to Born-Infeld
nonlinear electromagnetism, that is duality rotation invariant off shell and
that is known to be a root of an algebraic equation of fourth order, is a
hypergeometric function.Comment: 20 pages. Contribution to the proceedings of the conference BUDS2013,
Frascat
One-loop Regularization of Supergravity II: The Dilaton and the Superfield Formulation
The on-shell regularization of the one-loop divergences of supergravity
theories is generalized to include a dilaton of the type occurring in effective
field theories derived from superstring theory, and the superfield structure of
the one-loop corrections is given. Field theory anomalies and quantum
contributions to soft supersymmetry breaking are discussed. The latter are
sensitive to the precise choice of couplings that generate Pauli-Villars
masses, which in turn reflect the details of the underlying theory above the
scale of the effective cut-off. With a view to the implementation the
Green-Schwarz and other mechanisms for canceling field theory anomalies under a
U(1) gauge transformation and under the T-duality group of modular
transformations, we show that the K\"ahler potential renormalization for the
untwisted sector of orbifold compactification can be made invariant under these
groups.Comment: 46 pages, full postscript also available from
http://phyweb.lbl.gov/theorygroup/papers/43259.p
Generalization of Sharing in Behaviorally Handicapped Preschool Children
This study investigated the effects of a training package for increasing the sharing behavior of seven behaviorally handicapped preschool children in a freeplay setting and evaluated the generalization of training effects to a recess period. The 12-day training program in freeplay consisted of instructions, modeling, behavioral rehearsal, and in-session teacher prompts and praise regarding sharing skills
One-Loop Pauli-Villars Regularization of Supergravity I: Canonical Gauge Kinetic Energy
It is shown that the one-loop coefficients of on-shell operators of standard
supergravity with canonical gauge kinetic energy can be regulated by the
introduction of Pauli-Villars chiral and abelian gauge multiplets, subject to a
condition on the matter representations of the gauge group. Aspects of the
anomaly structure of these theories under global nonlinear symmetries and an
anomalous gauge symmetry are discussed.Comment: 46 pages, full postscript also available from
http://phyweb.lbl.gov/theorygroup/papers/preprints.html/41981.ps . Misprints
and errors in equations present in the original version have been correcte
Self-Duality in Nonlinear Electromagnetism
We discuss duality invariant interactions between electromagnetic fields and
matter. The case of scalar fields is treated in some detail.Comment: 10 pages, full postscript also available from
http://theor1.lbl.gov/www/theorygroup/papers/40770.p
The Holographic Dual of 2+1 Dimensional QFTs with N=1 SUSY and Massive Fundamental Flavours
The Maldacena Nastase solution is generalised to include massive fundamental
matter through the addition of a flavour profile. This gives a holographic dual
to N=1 SYM-CS with massive fundamental matter with a singularity free IR. We
study this solution in some detail confirming confinement and asymptotic
freedom. A recently proposed solution generating technique is then applied
which results in a new type-IIA supergravity solution. In a certain limit the
geometry of this solution is asymptotically AdS_4X Y, where Y is the metric at
the base of the Bryant-Salamon G_2 cone, which has topology S^3XS^3.Comment: 31 pages plus appendices, 6 figures. v3: Typos corrected, version to
appear in JHE
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