71 research outputs found
A Note on UV/IR Mixing and Non-Commutative Instanton Calculus
We estimate the instanton-induced vacuum energy in non-commutative U(1)
Yang-Mills theory in four dimensions. In the dilute gas approximation, it is
found to be plagued by infrared divergences, as a result of UV/IR mixing.Comment: 17 pages, LaTeX2
Gauge Independence of IR singularities in Non-Commutative QFT - and Interpolating Gauges
IR divergences of a non-commutative U(1) Maxwell theory are discussed at the
one-loop level using an interpolating gauge to show that quadratic IR
divergences are independent not only from a covariant gauge fixing but also
independent from an axial gauge fixing.Comment: 11 pages, 2 figures, v1 minor correction
Seiberg-Witten map for noncommutative super Yang-Mills theory
In this letter we derive the Seiberg-Witten map for noncommutative super
Yang-Mills theory in Wess-Zumino gauge. Following (and using results of)
hep-th/0108045 we split the observer Lorentz transformations into a covariant
particle Lorentz transformation and a remainder which gives directly the
Seiberg-Witten differential equations. These differential equations lead to a
theta-expansion of the noncommutative super Yang-Mills action which is
invariant under commutative gauge transformations and commutative observer
Lorentz transformation, but not invariant under commutative supersymmetry
transformations: The theta-expansion of noncommutative supersymmetry leads to a
theta-dependent symmetry transformation. For this reason the Seiberg-Witten map
of super Yang-Mills theory cannot be expressed in terms of superfields.Comment: 9 page
Noncommutative Lorentz Symmetry and the Origin of the Seiberg-Witten Map
We show that the noncommutative Yang-Mills field forms an irreducible
representation of the (undeformed) Lie algebra of rigid translations, rotations
and dilatations. The noncommutative Yang-Mills action is invariant under
combined conformal transformations of the Yang-Mills field and of the
noncommutativity parameter \theta. The Seiberg-Witten differential equation
results from a covariant splitting of the combined conformal transformations
and can be computed as the missing piece to complete a covariant conformal
transformation to an invariance of the action.Comment: 20 pages, LaTeX. v2: Streamlined proofs and extended discussion of
Lorentz transformation
One Loop Renormalizability of Spontaneously Broken Gauge Theory with a Product of Gauge Groups on Noncommutative Spacetime: the U(1) x U(1) Case
A generalization of the standard electroweak model to noncommutative
spacetime would involve a product gauge group which is spontaneously broken.
Gauge interactions in terms of physical gauge bosons are canonical with respect
to massless gauge bosons as required by the exact gauge symmetry, but not so
with respect to massive ones; and furthermore they are generally asymmetric in
the two sets of gauge bosons. On noncommutative spacetime this already occurs
for the simplest model of U(1) x U(1). We examine whether the above feature in
gauge interactions can be perturbatively maintained in this model. We show by a
complete one loop analysis that all ultraviolet divergences are removable with
a few renormalization constants in a way consistent with the above structure.Comment: 24 pages, figures using axodraw; version 2: a new ref item [4] added
to cite efforts to all orders, typos fixed and minor rewordin
Perturbative Chern-Simons Theory on Noncommutative R^3
A U(N) Chern-Simons theory on noncommutative is constructed
as a \q-deformed field theory. The model is characterized by two symmetries:
the BRST-symmetry and the topological linear vector supersymmetry. It is shown
that the theory is finite and \q_{\m\n}-independent at the one loop level and
that the calculations respect the restriction of the topological supersymmetry.
Thus the topological \q-deformed Chern-Simons theory is an example of a model
which is non-singular in the limit \q \to 0.Comment: 10 pages, 3 figures. Added loop calculation, conclusions unchanged,
some references adde
Non-renormalizability of noncommutative SU(2) gauge theory
We analyze the divergent part of the one-loop effective action for the
noncommutative SU(2) gauge theory coupled to the fermions in the fundamental
representation. We show that the divergencies in the 2-point and the 3-point
functions in the -linear order can be renormalized, while the
divergence in the 4-point fermionic function cannot.Comment: 15 pages, results presented at ESI 2d dilaton gravity worksho
Non-commutative U(1) Super-Yang-Mills Theory: Perturbative Self-Energy Corrections
The quantization of the non-commutative N=1, U(1) super-Yang-Mills action is
performed in the superfield formalism. We calculate the one-loop corrections to
the self-energy of the vector superfield. Although the power-counting theorem
predicts quadratic ultraviolet and infrared divergences, there are actually
only logarithmic UV and IR divergences, which is a crucial feature of
non-commutative supersymmetric field theories.Comment: 18 pages, latex, uses feynmf package; references added, Wess-Zumino
gauge remove
On the energy-momentum tensor in non-commutative gauge theories
We study the properties of the energy-momentum tensor in non-commutative
gauge theories by coupling them to a weak external gravitational field. In
particular, we show that the stress tensor of such a theory coincides exactly
with that derived from a theory where a Seiberg-Witten map has been implemented
(namely, the procedure is commutative). Various other interesting features are
also discussed.Comment: 3 page
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