Actions for The trace anomaly and massless scalar degrees of freedom [electronic resource].

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The trace anomaly and massless scalar degrees of freedom [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2008.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Additional Creators
Los Alamos National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. Considering first the axial anomaly and using QED as an example, we compute the full one-loop triangle amplitude of the fermionic stress tensor with two current vertices, {open_square}T{sup μν}J{sup α}J{sup β}, and exhibit the scalar pole in this amplitude associated with the trace anomaly, in the limit of zero electron mass m→0. To emphasize the infrared aspect of the anomaly, we use a dispersive approach and show that this amplitude and the existence of the massless scalar pole is determined completely by its ultraviolet finite terms, together with the requirements of Poincare invariance of the vacuum, Bose symmetry under interchange of J{sup α} and J{sup β}, and vector current and stress-tensor conservation. We derive a sum rule for the appropriate positive spectral function corresponding to the discontinuity of the triangle amplitude, showing that it becomes proportional to δ(k²) and therefore contains a massless scalar intermediate state in the conformal limit of zero electron mass. The effective action corresponding to the trace of the triangle amplitude can be expressed in local form by the introduction of two scalar auxiliary fields which satisfy massless wave equations. These massless scalar degrees of freedom couple to classical sources, contribute to gravitational scattering processes, and can have long range gravitational effects.
Report Numbers
E 1.99:la-ur-08-06329
E 1.99: la-ur-08-6329
la-ur-08-6329
la-ur-08-06329
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Note
Published through SciTech Connect.
01/01/2008.
"la-ur-08-06329"
" la-ur-08-6329"
Pjys. Review D ISSN 1550-7998; PRVDAQ FT
Mottola, Emil; Gianotti, Maurizio.
Funding Information
AC52-06NA25396
View MARC record | catkey: 13822584