Unimodular Proca Theory: Breaking the U(1) gauge symmetry of unimodular gravity via a mass term

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Autori principali: Isichei, Raymond, Magueijo, João
Natura: Preprint
Pubblicazione: 2023
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author Isichei, Raymond
Magueijo, João
author_facet Isichei, Raymond
Magueijo, João
contents 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 four-volume time vector ${\cal T}^{i}\approx0$. 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 (gauge-invariant) zero-mode receives modified dynamics. The implications are investigated, with the phenomenology depending crucially on the target ``constant''.
format Preprint
id arxiv_https___arxiv_org_abs_2305_09380
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Unimodular Proca Theory: Breaking the U(1) gauge symmetry of unimodular gravity via a mass term
Isichei, Raymond
Magueijo, João
High Energy Physics - Theory
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
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 four-volume time vector ${\cal T}^{i}\approx0$. 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 (gauge-invariant) zero-mode receives modified dynamics. The implications are investigated, with the phenomenology depending crucially on the target ``constant''.
title Unimodular Proca Theory: Breaking the U(1) gauge symmetry of unimodular gravity via a mass term
topic High Energy Physics - Theory
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2305.09380