115 research outputs found
Non-commutativity and Supersymmetry
We study the extent to which the gauge symmetry of abelian Yang-Mills can be
deformed under two conditions: first, that the deformation depend on a two-form
scale. Second, that the deformation preserve supersymmetry. We show that (up to
a single parameter) the only allowed deformation is the one determined by the
star product. We then consider the supersymmetry algebra satisfied by NCYM
expressed in commutative variables. The algebra is peculiar since the
supercharges are not gauge-invariant. However, the action, expressed in
commutative variables, appears to be quadratic in fermions to all orders in
theta.Comment: 21 pages, LaTeX; a reference adde
Structure in Supersymmetric Yang-Mills Theory
We show that requiring sixteen supersymmetries in quantum mechanical gauge
theory implies the existence of a web of constrained interactions. Contrary to
conventional wisdom, these constraints extend to arbitrary orders in the
momentum expansion.Comment: 22 pages, LaTe
Effective Dynamics of the Matrix Big Bang
We study the leading quantum effects in the recently introduced Matrix Big
Bang model. This amounts to a study of supersymmetric Yang-Mills theory
compactified on the Milne orbifold. We find a one-loop potential that is
attractive near the Big Bang. Surprisingly, the potential decays very rapidly
at late times, where it appears to be generated by D-brane effects. Usually,
general covariance constrains the form of any effective action generated by
renormalization group flow. However, the form of our one-loop potential seems
to violate these constraints in a manner that suggests a connection between the
cosmological singularity and long wavelength, late time physics.Comment: 22 pages, LaTeX; some minor changes; an improved discussion of the
potentia
Analyzing Multi-Field Tunneling With Exact Bounce Solutions
We study multi-field tunneling using exact solutions for additive potentials.
We introduce a binomial potential with non-integer powers that could be
considered a generalization of the Fubini instanton potential. Using
scaling arguments, we show that for multi-field potentials taller and wider
barriers may still lead to a smaller bounce action.Comment: 16 pages, 2 figures, 1 tabl
Duals of noncommutative supersymmetric U(1) gauge theory
Parent actions for component fields are utilized to derive the dual of
supersymmetric U(1) gauge theory in 4 dimensions. Generalization of the
Seiberg-Witten map to the component fields of noncommutative supersymmetric
U(1) gauge theory is analyzed. Through this transformation we proposed parent
actions for noncommutative supersymmetric U(1) gauge theory as generalization
of the ordinary case.Duals of noncommutative supersymmetric U(1) gauge theory
are obtained. Duality symmetry under the interchange of fields with duals
accompanied by the replacement of the noncommutativity parameter
\Theta_{\mu\nu} with \tilde{\Theta}_{\mu \nu} =
\epsilon_{\mu\nu\rho\sigma}\Theta^{\rho\sigma} of the non--supersymmetric case
is broken at the level of actions. We proposed a noncommutative parent action
for the component fields which generates actions possessing this duality
symmetry.Comment: Typos corrected. Version which will appear in JHE
Leptogenesis from Pseudo-Scalar Driven Inflation
We examine recent claims for a considerable amount of leptogenesis, in some
inflationary scenarios, through the gravitational anomaly in the lepton number
current. We find that when the short distances contributions are properly
included the amount of lepton number generated is actually much smaller.Comment: JHEP style, 11 pages. Corrected typ
Conformal Symmetry and A New Gauge in the Matrix Model
We generalize the background gauge in the Matrix model to propose a new gauge
which is useful for discussing the conformal symmetry. In this gauge, the
special conformal transformation (SCT) as the isometry of the near-horizon
geometry of the D-particle solution is directly reproduced with the correct
coefficient as the quantum correction to the SCT in the Matrix model. We also
present a general argument for the relation between the gauge choice and the
field redefinition in the Matrix model.Comment: 17 pages, LaTeX, no figures; v2: Introduction modified, references
added and typos corrected; v3: Introduction changed; v4: Eq.(12) corrected;
v5: final version to appear in Phys. Rev.
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