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Title: Non-minimal derivative couplings of the composite metric

Abstract

In the context of massive gravity, bi-gravity and multi-gravity non-minimal matter couplings via a specific composite effective metric were investigated recently. Even if these couplings generically reintroduce the Boulware-Deser ghost, this composite metric is unique in the sense that the ghost reemerges only beyond the decoupling limit and the matter quantum loop corrections do not detune the potential interactions. We consider non-minimal derivative couplings of the composite metric to matter fields for a specific subclass of Horndeski scalar-tensor interactions. We first explore these couplings in the mini-superspace and investigate in which scenario the ghost remains absent. We further study these non-minimal derivative couplings in the decoupling-limit of the theory and show that the equation of motion for the helicity-0 mode remains second order in derivatives. Finally, we discuss preliminary implications for cosmology.

Authors:
 [1];  [2]
  1. Nordita, KTH Royal Institute of Technology and Stockholm University,Roslagstullsbacken 23, 10691 Stockholm (Sweden)
  2. (Sweden)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22458402
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 11; Other Information: PUBLISHER-ID: JCAP11(2015)005; OAI: oai:repo.scoap3.org:12522; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CORRECTIONS; COSMOLOGY; COUPLINGS; DECOUPLING; EQUATIONS OF MOTION; GRAVITATION; HELICITY; INTERACTIONS; METRICS

Citation Formats

Heisenberg, Lavinia, and Department of Physics & The Oskar Klein Centre,AlbaNova University Centre, 10691 Stockholm. Non-minimal derivative couplings of the composite metric. United States: N. p., 2015. Web. doi:10.1088/1475-7516/2015/11/005.
Heisenberg, Lavinia, & Department of Physics & The Oskar Klein Centre,AlbaNova University Centre, 10691 Stockholm. Non-minimal derivative couplings of the composite metric. United States. doi:10.1088/1475-7516/2015/11/005.
Heisenberg, Lavinia, and Department of Physics & The Oskar Klein Centre,AlbaNova University Centre, 10691 Stockholm. 2015. "Non-minimal derivative couplings of the composite metric". United States. doi:10.1088/1475-7516/2015/11/005.
@article{osti_22458402,
title = {Non-minimal derivative couplings of the composite metric},
author = {Heisenberg, Lavinia and Department of Physics & The Oskar Klein Centre,AlbaNova University Centre, 10691 Stockholm},
abstractNote = {In the context of massive gravity, bi-gravity and multi-gravity non-minimal matter couplings via a specific composite effective metric were investigated recently. Even if these couplings generically reintroduce the Boulware-Deser ghost, this composite metric is unique in the sense that the ghost reemerges only beyond the decoupling limit and the matter quantum loop corrections do not detune the potential interactions. We consider non-minimal derivative couplings of the composite metric to matter fields for a specific subclass of Horndeski scalar-tensor interactions. We first explore these couplings in the mini-superspace and investigate in which scenario the ghost remains absent. We further study these non-minimal derivative couplings in the decoupling-limit of the theory and show that the equation of motion for the helicity-0 mode remains second order in derivatives. Finally, we discuss preliminary implications for cosmology.},
doi = {10.1088/1475-7516/2015/11/005},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 11,
volume = 2015,
place = {United States},
year = 2015,
month =
}
  • In the context of massive gravity, bi-gravity and multi-gravity non-minimal matter couplings via a specific composite effective metric were investigated recently. Even if these couplings generically reintroduce the Boulware-Deser ghost, this composite metric is unique in the sense that the ghost reemerges only beyond the decoupling limit and the matter quantum loop corrections do not detune the potential interactions. We consider non-minimal derivative couplings of the composite metric to matter fields for a specific subclass of Horndeski scalar-tensor interactions. We first explore these couplings in the mini-superspace and investigate in which scenario the ghost remains absent. We further study thesemore » non-minimal derivative couplings in the decoupling-limit of the theory and show that the equation of motion for the helicity-0 mode remains second order in derivatives. Finally, we discuss preliminary implications for cosmology.« less
  • We study the gravitational production of heavy X-particles of mass of the order of the inflaton mass, produced after the end of inflation. We find that, in the presence of a derivative coupling of the inflaton field or of the X-field to the Einstein tensor, the number of gravitationally produced particles is suppressed as the strength of the coupling is increased.
  • We perform a combined perturbation and observational investigation of the scenario of non-minimal derivative coupling between a scalar field and curvature. First we extract the necessary condition that ensures the absence of instabilities, which is fulfilled more sufficiently for smaller coupling values. Then using Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO), and Cosmic Microwave Background (CMB) observations, we show that, contrary to its significant effects on inflation, the non-minimal derivative coupling term has a negligible effect on the universe acceleration, since it is driven solely by the usual scalar-field potential. Therefore, the scenario can provide a unified picture ofmore » early and late time cosmology, with the non-minimal derivative coupling term responsible for inflation, and the usual potential responsible for late-time acceleration. Additionally, the fact that the necessary coupling term does not need to be large, improves the model behavior against instabilities.« less