Structures in multiple spin-2 interactions

We present the construction of a gravitational action including an infinite series of higher derivative terms. The outcome is a classically consistent completion of a well-studied quadratic curvature theory. The closed form for the full action is ghost-free bimetric theory, describing the interactions of a massive and a massless spin-2 field. At energies much smaller than the spin-2 mass scale, the theory reduces to general relativity. For energies comparable to the spin-2 mass, the higher derivative terms completing the Einstein-Hilbert action capture the effects of the additional massive spin-2 field. The theory is only ghost-free when the full series of higher derivatives is kept.

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“…It would also be interesting to study the case of multiple heavy spin-2 modes and thereby continue investigations started in Ref. [38].…”

Section: Discussionmentioning

confidence: 95%

Ghost-free infinite derivative gravity

Gording

Schmidt-May

2018

J. High Energ. Phys.

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“…[26] compares multimetric models in the metric and vierbein formalism, but does not look at cosmological solutions, while Ref. [69] examines maximally-symmetric solutions in multigravity.…”

Section: Introductionmentioning

confidence: 99%

Cosmology with three interacting spin-2 fields

et al. 2016

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Theories of massive gravity with one or two dynamical metrics generically lack stable and observationally-viable cosmological solutions that are distinguishable from ΛCDM. We consider an extension to trimetric gravity, with three interacting spin-2 fields which are not plagued by the Boulware-Deser ghost. We systematically explore every combination with two free parameters in search of background cosmologies that are competitive with ΛCDM. For each case we determine whether the expansion history satisfies viability criteria, and whether or not it contains beyond-ΛCDM phenomenology. Among the many models we consider, there are only three cases that seem to be both viable and distinguishable from standard cosmology. One of the models has only one free parameter and displays a crossing from above to below the phantom divide. The other two provide scaling behavior, although they contain future singularities that need to be studied in more detail. These models possess interesting features that make them compelling targets for a full comparison to observations of both cosmological expansion history and structure formation.

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“…In this model the accelerated expansion of the Universe is due to the interaction of the gravitons, there is no need of dark energy. A natural extension of [10] corresponds to multi-gravity models with more than one massive graviton, see [16][17][18][19] and references therein.…”

Section: Introductionmentioning

confidence: 99%

Reconciling absence of vDVZ discontinuity with absence of ghosts in nonlocal linearized gravity

Dalmazi

2023

Class. Quantum Grav.

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The modern massive gravity theories resolve a historical tension between the absenceof the so called vDVZ mass discontinuity and the absence of ghosts via a fine tunedgravitational potential and a sophisticated screening mechanism. Those theories haveoriginated the modern covariant bimetric models which are local, ghost free and cos mologically viable apparently, they contain a massive plus a massless graviton in thespectrum. It seems hard to solve the mentioned tension if we do insist in a model witha minimal number of degrees of freedom, with only one massive spin-2 particle in thespectrum, even if we allow nonlocal theories. Here we show that this problem can be cir cumvented in linearized nonlocal theories by the introduction of exponential terms withinfinite derivatives. The model admits non linear completions via nonlocal quadraticterms in curvatures. We also investigate the role of the exponential factors in linearizedmodels where the graviton remains massless and a mass scale is introduced via nonlocalterms, they are also ghost free and approach the Einstein-Hilbert theory as we go muchabove the introduced mass scale.

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Structures in multiple spin-2 interactions

Cited by 8 publications

References 101 publications

Ghost-free infinite derivative gravity

Ghost-free infinite derivative gravity

Cosmology with three interacting spin-2 fields

Reconciling absence of vDVZ discontinuity with absence of ghosts in nonlocal linearized gravity

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