Unimodular proca theory: breaking the U(1) gauge symmetry of unimodular gravity via a mass term
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Published version
Author(s)
Isichei, Raymond
Magueijo, João
Type
Journal Article
Abstract
We study the Hamiltonian structure of
unimodular-like theories, where the cosmological constant
(or other supposed constants of nature) are demoted from
fixed parameters to classical constants of motion. No new
local degrees of freedom are present as a result of a U(1)
gauge invariance of the theory. Hamiltonian analysis of the
action reveals that the only possible gauge fixing that can
be enforced is setting the spatial components of the fourvolume time vector T i ≈ 0. As a consequence of this, the
gauge-fixed unimodular path integral is equivalent to the minisuperspace unimodular path integral. However, should we
break the U(1) gauge invariance, two things happen: a massless propagating degree of freedom appears, and the (gaugeinvariant) zero-mode receives modified dynamics. The implications are investigated, with the phenomenology depending
crucially on the target “constant”.
unimodular-like theories, where the cosmological constant
(or other supposed constants of nature) are demoted from
fixed parameters to classical constants of motion. No new
local degrees of freedom are present as a result of a U(1)
gauge invariance of the theory. Hamiltonian analysis of the
action reveals that the only possible gauge fixing that can
be enforced is setting the spatial components of the fourvolume time vector T i ≈ 0. As a consequence of this, the
gauge-fixed unimodular path integral is equivalent to the minisuperspace unimodular path integral. However, should we
break the U(1) gauge invariance, two things happen: a massless propagating degree of freedom appears, and the (gaugeinvariant) zero-mode receives modified dynamics. The implications are investigated, with the phenomenology depending
crucially on the target “constant”.
Date Issued
2024-04
Date Acceptance
2024-04-12
Citation
European Physical Journal C: Particles and Fields, 2024, 84 (4)
ISSN
1124-1861
Publisher
SpringerOpen
Journal / Book Title
European Physical Journal C: Particles and Fields
Volume
84
Issue
4
Copyright Statement
© The Author(s) 2024
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Identifier
http://dx.doi.org/10.1140/epjc/s10052-024-12803-9
Publication Status
Published
Article Number
436
Date Publish Online
2024-04-27