Emergent modified gravity: Polarized Gowdy model on a torus

Abstract

New covariant theories of emergent modified gravity exist not only in spherically symmetric models, as previously found, but also in polarized Gowdy systems that have a local propagating degree of freedom. Several explicit versions are derived here, depending on various modification functions. These models do not have instabilities from higher time derivatives, and a large subset is compatible with gravitational waves and minimally coupled massless matter fields travelling at the same speed. Interpreted as models of loop quantum gravity, covariant Hamiltonian constraints derived from the covariance conditions found in polarized Gowdy systems are more restricted than those in spherical symmetry, requiring new forms of holonomy modifications with an anisotropy dependence that has not been considered before. Assuming homogeneous space, the models provide access to the full anisotropy parameters of modified Bianchi I dynamics, in which case different fates of the classical singularity are realized depending on the specific class of modifications.

55 pages, two figures

References in corpus (16)

• Multi-messenger Observations of a Binary Neutron Star Merger
• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source
• Spherically Symmetric Quantum Geometry: States and Basic Operators
• Hybrid Quantum Gowdy Cosmology: Combining Loop and Fock Quantizations
• Loop quantum cosmology and inhomogeneities
• A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a
• Inhomogeneous Loop Quantum Cosmology: Hybrid Quantization of the Gowdy Model
• Matter in inhomogeneous loop quantum cosmology: the Gowdy $T^3$ model
• Emergent modified gravity: Covariance regained
• Singularity resolution by holonomy corrections: Spherical charged black holes in cosmological backgrounds
• Loop quantization of the Gowdy model with local rotational symmetry
• Loop Quantization of Polarized Gowdy Model on $T^3$: Kinematical States and Constraint Operators
• Loop Quantization of Polarized Gowdy Model on $T^3$: Classical Theory
• Emergent Modified Gravity
• MONDified Gravity

Cited by in corpus (1)

• Lessons for loop quantum gravity from emergent modified gravity