Modified gravity without new degrees of freedom

Abstract

We show that the new type of "non-metric" gravity theories introduced independently by Bengtsson and Krasnov can in fact be reexpressed explicitely as a metrical theory coupled to an auxiliary field. We unravel why such theories possess only one propagating graviton by looking at the quadratic perturbation around a fixed solution. And we give a general construction principle with a new class of example of such modified gravity theories still possessing only two propagating degrees of freedom.

19 pages

References in corpus (7)

• Flipped spinfoam vertex and loop gravity
• Modified-Source Gravity and Cosmological Structure Formation
• Consistent Spin-Two Coupling and Quadratic Gravitation
• On deformations of Ashtekar's constraint algebra
• Renormalizable Non-Metric Quantum Gravity?
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Cited by in corpus (11)

• Modified Gravity and Cosmology
• Effective metric Lagrangians from an underlying theory with two propagating degrees of freedom
• $BF$ gravity
• Bi-metric theory of gravity from the non-chiral Plebanski action
• On the Relations between Gravity and BF Theories
• Towards effective actions for the continuum limit of spin foams
• Gravity-Yang-Mills-Higgs unification by enlarging the gauge group
• A note on the Plebanski action with cosmological constant and an Immirzi parameter
• Pauli-Fierz mass term in modified Plebanski gravity
• Spherically symmetric black holes in minimally modified self-dual gravity
• Hamiltonian consistency of the gravitational constraint algebra under deformations