4,856 research outputs found
One-loop conformal anomaly in an implicit momentum space regularization framework
In this paper we consider matter fields in a gravitational background in
order to compute the breaking of the conformal current at one-loop order.
Standard perturbative calculations of conformal symmetry breaking expressed by
the non-zero trace of the energy-momentum tensor have shown that some violating
terms are regularization dependent, which may suggest the existence of spurious
breaking terms in the anomaly. Therefore, we perform the calculation in a
momentum space regularization framework in which regularization dependent terms
are judiciously parametrized. We compare our results with those obtained in the
literature and conclude that there is an unavoidable arbitrariness in the
anomalous term .Comment: in European Physical Journal C, 201
Conductivity of Coulomb interacting massless Dirac particles in graphene: Regularization-dependent parameters and symmetry constraints
We compute the Coulomb correction to the a. c. conductivity of
interacting massless Dirac particles in graphene in the collisionless limit
using the polarization tensor approach in a regularization independent
framework. Arbitrary parameters stemming from differences between
logarithmically divergent integrals are fixed on physical grounds exploiting
only spatial rotational invariance of the model which amounts to
transversality of the polarization tensor. Consequently is
unequivocally determined to be within this effective model. We
compare our result with explicit regularizations and discuss the origin of
others results for found in the literature
Ultraviolet and Infrared Divergences in Implicit Regularization: a Consistent Approach
Implicit Regularization is a 4-dimensional regularization initially conceived
to treat ultraviolet divergences. It has been successfully tested in several
instances in the literature, more specifically in those where Dimensional
Regularization does not apply. In the present contribution we extend the method
to handle infrared divergences as well. We show that the essential steps which
rendered Implicit Regularization adequate in the case of ultraviolet
divergences have their counterpart for infrared ones. Moreover we show that a
new scale appears, typically an infrared scale which is completely independent
of the ultraviolet one. Examples are given.Comment: 9 pages, version to appear in Mod. Phys. Lett.
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