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O. Piguet

Publications and source records attributed to O. Piguet.

At least 19 recordsLinked to original sources
arXiv2017

No radiative generation of Chern-Simons-like term in Lorentz-violating QED: dealing with IR divergences

The issue intensively claimed in the literature on the generation of a CPT-odd and Lorentz violating Chern-Simons-like term by radiative corrections owing to a CPT violating interaction -- the axial coupling of fermions with a constant vector field $b_\m$ -- is mistaken. The presence of massless gauge field triggers IR divergences that might show up from the UV subtractions, therefore, so as to deal with the (actual physical) IR divergences, the Lowenstein-Zimmermann subtraction scheme, in the framework of BPHZL renormalization method, has to be adopted. The proof on the non generation of such a Chern-Simons-like term is done, independent of any kind of regularization scheme, at all orders in perturbation theory.

hep-th↗
arXiv2012

All orders renormalizability of a Lorentz and CPT violating quantum electrodynamics

Renormalizability of the (minimal) single-fermion QED extension is investigated at all orders of perturbation theory in the framework of algebraic renormalization, a regularization-independent method. Relative to the standard QED, new structures that could lead to gauge anomalies are identified. Nevertheless, even if the anomaly coefficients fail to vanish in the general case, they shall be absent provided we require invariance of the action under C and/or PT transformations. Stability is also verified in this case, hence full renormalizability is attained.

hep-th↗
arXiv2006

On 1+1 Dimensional Galilean Supersymmetry in Ultracold Quantum Gases

We discuss a 1+1 dimensional Galilean invariant model recently introduced in connection with ultracold quantum gases. After showing its relation to a nonrelativistic 2+1 Chern-Simons matter system, we identify the generators of the supersymmetry and its relation with the existence of self-dual equations

cond-mat.other↗
arXiv2004

Symmetries and observables in topological gravity

After a brief review of topological gravity, we present a superspace approach to this theory. This formulation allows us to recover in a natural manner various known results and to gain some insight into the precise relationship between different approaches to topological gravity. Though the main focus of our work is on the vielbein formalism, we also discuss the metric approach and its relationship with the former formalism.

gr-qc↗
arXiv2004

Observables in Topological Theories: A Superspace Formulation

Observables of topological Yang-Mills theory were defined by Witten as the classes of an equivariant cohomology. We propose to define them alternatively as the BRST cohomology classes of a superspace version of the theory, where BRST invariance is associated to super Yang-Mills invariance. We provide and discuss the general solution of this cohomology.

hep-th↗
arXiv2001

On the symmetries of BF models and their relation with gravity

The perturbative finiteness of various topological models (e.g. BF models) has its origin in an extra symmetry of the gauge-fixed action, the so-called vector supersymmetry. Since an invariance of this type also exists for gravity and since gravity is closely related to certain BF models, vector supersymmetry should also be useful for tackling various aspects of quantum gravity. With this motivation and goal in mind, we first extend vector supersymmetry of BF models to generic manifolds by incorporating it into the BRST symmetry within the Batalin-Vilkovisky framework. Thereafter, we address the relationship between gravity and BF models, in particular for three-dimensional space-time.

hep-th↗
arXiv1999

An algebraic proof on the finiteness of Yang-Mills-Chern-Simons theory in D=3

A rigorous algebraic proof of the full finiteness in all orders of perturbation theory is given for the Yang-Mills-Chern-Simons theory in a general three-dimensional Riemannian manifold. We show the validity of a trace identity, playing the role of a local form of the Callan-Symanzik equation, in all loop orders, which yields the vanishing of the beta-functions associated to the topological mass and gauge coupling constant as well as the anomalous dimensions of the fields.

math-ph↗
arXiv1995

Five-Dimensional BF Theory and Four-Dimensional Current Algebra

We consider the relation between the five-dimensional BF model and a four-dimensional local current algebra from the point of view of perturbative local quantum field theory. We use an axial gauge fixing procedure and show that it allows for a well defined theory which actually can be solved exactly.

hep-th↗
arXiv1994

A Renormalized Supersymmetry in the Topological Yang-Mills Field Theory

We reconsider the algebraic BRS renormalization of Witten's topological Yang-Mills field theory by making use of a vector supersymmetry Ward identity which improves the finiteness properties of the model. The vector supersymmetric structure is a common feature of several topological theories. The most general local counterterm is determined and is shown to be a trivial BRS-coboundary.

hep-th↗
arXiv1994

Symmetries of the Chern-Simons Theory in the Axial Gauge, Manifold with Boundary

The field equations of the Chern-Simons theory quantized in the axial gauge are shown to be completely determined by supersymmetry Ward identities which express the invariance of the theory under the topological supersymmetry of Delduc, Gieres and Sorella together with the usual Slavnov identity without requiring any action principle.

hep-th↗
arXiv1993

Symmetries of the Chern-Simons Theory in the Axial Gauge

The Green functions of the Chern-Simons theory quantized in the axial gauge are shown to be calculable as the unique, exact solution of the Ward identities which express the invariance of the theory under the topological supersymmetry of Delduc, Gieres and Sorella.

hep-th↗