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Related papers: On the trace anomaly for Weyl fermions

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We review recent discussions regarding the parity-odd contribution to the trace anomaly of a chiral fermion. We pay special attention to the perturbative approach in terms of Feynman diagrams, comparing in detail the results obtained using…

High Energy Physics - Theory · Physics 2023-04-19 S. Abdallah , S. A. Franchino-Viñas , M. Fröb

We study the trace anomaly of a Weyl fermion in an abelian gauge background. Although the presence of the chiral anomaly implies a breakdown of gauge invariance, we find that the trace anomaly can be cast in a gauge invariant form. In…

High Energy Physics - Theory · Physics 2019-05-08 Fiorenzo Bastianelli , Matteo Broccoli

We study the trace and chiral anomalies of Weyl fermions in a non-abelian gauge background in four dimensions. Using a Pauli-Villars regularization we identify the trace anomaly, proving that it can be cast in a gauge invariant form, even…

High Energy Physics - Theory · Physics 2020-01-08 Fiorenzo Bastianelli , Matteo Broccoli

We calculate the trace anomaly of a Weyl fermion coupled to gravity by using Fujikawa's method supplemented by the choice of a consistent regulator. The latter is constructed out of Pauli-Villars regulating fields. The motivation for…

High Energy Physics - Theory · Physics 2016-12-19 Fiorenzo Bastianelli , Riccardo Martelli

Anomalous parity violation in four dimensions would be significant for phenomenology (baryogenesis, gravitational waves) and mathematical physics. Over the past decade, there has been a controversy in the literature as to whether free Weyl…

High Energy Physics - Theory · Physics 2024-11-04 Rémy Larue , Jérémie Quevillon , Roman Zwicky

In this paper, we study the problem of trace anomaly for a chiral fermion. To find whether there exists a parity-odd term (Pontryagin term), we use a modified Breitenlohner-Maison-'t Hooft-Veltman regularization and Fujikawa's method by a…

High Energy Physics - Theory · Physics 2023-04-14 Chang-Yong Liu

We compute the trace, diffeomorphism and Lorentz anomalies of a free Weyl fermion in a gravitational background field by path integral methods. This is achieved by regularising the variation of the determinant of the Weyl operator building…

High Energy Physics - Theory · Physics 2024-04-23 Rémy Larue , Jérémie Quevillon , Roman Zwicky

This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the…

High Energy Physics - Theory · Physics 2017-09-13 L. Bonora , M. Cvitan , P. Dominis Prester , A. Duarte Pereira , S. Giaccari , T. Stemberga

We revisit the conformal anomaly for a Weyl fermion in four dimensions that has generated some debate recently. We employ a perturbative expansion for the metric around Minkowski space, dimensional regularization and a Breitenlohner--Maison…

High Energy Physics - Theory · Physics 2024-11-07 S. Abdallah , S. A Franchino-Viñas , M. B. Fröb

We compute the parity-odd part of the Weyl anomaly for chiral fermions in a background gravitational field. We start from a manifestly real form of the Lagrangian (that is, not only real up to a total derivative), and we regularize it by…

High Energy Physics - Theory · Physics 2026-02-27 Enrique Alvarez , Luis Alvarez-Gaume , Jesus Anero , Carmelo P Martin

We revisit the computation of the trace anomaly for Weyl fermions using dimensional regularization. For a consistent treatment of the chiral gamma matrix $\gamma_*$ in dimensional regularization, we work in $n$ dimensions from the very…

High Energy Physics - Theory · Physics 2021-09-28 S. Abdallah , S. A. Franchino-Viñas , M. B. Fröb

The "parity" anomaly -- more accurately described as an anomaly in time-reversal or reflection symmetry -- arises in certain theories of fermions coupled to gauge fields and/or gravity in a spacetime of odd dimension. This anomaly has…

High Energy Physics - Theory · Physics 2016-12-07 Edward Witten

We study the coupling of a 2+1 dimensional non-relativistic spin 1/2 fermion to a curved Newton-Cartan geometry, using null reduction from an extra-dimensional relativistic Dirac action in curved spacetime. We analyze Weyl invariance in…

High Energy Physics - Theory · Physics 2017-09-13 Roberto Auzzi , Stefano Baiguera , Giuseppe Nardelli

In an analogy to the odd-dimensional case we define the parity anomaly as the part of the one-loop effective action for fermions associated with spectral asymmetry of the Dirac operator. This quantity is computed directly on…

High Energy Physics - Theory · Physics 2017-07-19 M. Kurkov , D. Vassilevich

We define the notion of Weyl anomalies, measuring the violation of local scale invariance, in interacting quantum field theory on curved spacetimes in the framework of locally covariant field theory. We discuss some general properties of…

High Energy Physics - Theory · Physics 2025-11-13 Markus B. Fröb , Jochen Zahn

We investigate the trace anomaly of a chiral fermion in dimensional regularization, considering in detail the simplest case of coupling to an abelian gauge field. We apply the Breitenlohner-Maison/'t Hooft-Veltman prescription for dealing…

High Energy Physics - Theory · Physics 2022-08-17 Fiorenzo Bastianelli , Luca Chiese

It is well known that a quantized two-dimensional Weyl fermion coupled to gravity spoils general covariance and breaks the covariant conservation of the energy-momentum tensor. In this brief article, we point out that the quantum…

High Energy Physics - Theory · Physics 2019-05-20 Pau Beltrán-Palau , Jose Navarro-Salas , Silvia Pla

Starting from the Ginsparg-Wilson relation, a general construction of chiral gauge theories on the lattice is described. Local and global anomalies are easily discussed in this framework and a closed expression for the effective action can…

High Energy Physics - Lattice · Physics 2008-11-26 Martin Lüscher

Unconventional lattice fermions with high degeneracies beyond Weyl and Dirac fermions have attracted intensive attention in recent years. In this paper, attention is drawn to the pseudospin-1 Maxwell fermions and the $(2+1)$ dimensional…

Strongly Correlated Electrons · Physics 2020-08-26 Jiang Zhou , Xiaosi Qi , Yajie Wu , Su-Peng Kou

We show that Weyl semimetals exhibit a mixed axial-torsional anomaly in the presence of axial torsion, a concept exclusive of these materials with no known natural fundamental interpretation in terms of the geometry of spacetime. This…

Mesoscale and Nanoscale Physics · Physics 2019-02-13 Yago Ferreiros , Yaron Kedem , Emil J. Bergholtz , Jens H. Bardarson
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