A no-go theorem shows that negative effective mass squared for the vector field in vector-tensor gravity always accompanies ghost or gradient instabilities, blocking spontaneous vectorization in stationary axisymmetric black holes.
Cosmology in generalized Proca theories
8 Pith papers cite this work. Polarity classification is still indexing.
abstract
We consider a massive vector field with derivative interactions that propagates only the 3 desired polarizations (besides two tensor polarizations from gravity) with second-order equations of motion in curved space-time. The cosmological implications of such generalized Proca theories are investigated for both the background and the linear perturbation by taking into account the Lagrangian up to quintic order. In the presence of a matter fluid with a temporal component of the vector field, we derive the background equations of motion and show the existence of de Sitter solutions relevant to the late-time cosmic acceleration. We also obtain conditions for the absence of ghosts and Laplacian instabilities of tensor, vector, and scalar perturbations in the small-scale limit. Our results are applied to concrete examples of the general functions in the theory, which encompass vector Galileons as a specific case. In such examples, we show that the de Sitter fixed point is always a stable attractor and study viable parameter spaces in which the no-ghost and stability conditions are satisfied during the cosmic expansion history.
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Field equation analysis near infinity in massive Hellings-Nordtvedt theory restricts the model to two single-coupling sectors; the A²R sector yields asymptotically flat Schwarzschild black holes with radial vector fields and neutron stars with measurable deviations from GR while satisfying weak-fiel
Spacetime symmetries generate stealth Proca vector fields on arbitrary backgrounds, enabling exact Proca-haired rotating black holes in all dimensions.
In scalar-vector-tensor gravity, the vector-curvature coupling alters neutron star mass-radius curves and radial oscillation frequencies while preserving the coincidence of maximum mass with the onset of radial instability.
Quasinormal frequencies for massless fields in Proca-hairy de Sitter black holes show scalar ℓ=0 modes most sensitive to hair parameter Q, with damping weakening near the three-horizon regime.
Extended Proca-Nuevo gravity modifies the background expansion via a vector field algebraic constraint but leaves the matter growth equation identical to general relativity.
Applies sixth-order WKB to compute grey-body factors for test fields on generalized Proca black holes with effective de Sitter scale, finding that scalar mass and couplings raise barriers, suppress low-frequency transmission, and affect thermodynamics.
A review thesis covering Mukhanov parametrization, general scalar-tensor theories, and new slow-roll techniques for canonical and noncanonical inflation observables.
citing papers explorer
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No-go theorem for spontaneous vectorization
A no-go theorem shows that negative effective mass squared for the vector field in vector-tensor gravity always accompanies ghost or gradient instabilities, blocking spontaneous vectorization in stationary axisymmetric black holes.
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Black holes and neutron stars in massive Hellings-Nordtvedt theory
Field equation analysis near infinity in massive Hellings-Nordtvedt theory restricts the model to two single-coupling sectors; the A²R sector yields asymptotically flat Schwarzschild black holes with radial vector fields and neutron stars with measurable deviations from GR while satisfying weak-fiel
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Proca-type Hair of Rotating Black Holes in Higher Dimensions
Spacetime symmetries generate stealth Proca vector fields on arbitrary backgrounds, enabling exact Proca-haired rotating black holes in all dimensions.
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Radial Oscillations of Neutron Stars with Vector-Induced Scalar Hair
In scalar-vector-tensor gravity, the vector-curvature coupling alters neutron star mass-radius curves and radial oscillation frequencies while preserving the coincidence of maximum mass with the onset of radial instability.
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Quasinormal Spectra of Fields of Various Spin in Asymptotically de Sitter Black Holes within Generalized Proca Theory
Quasinormal frequencies for massless fields in Proca-hairy de Sitter black holes show scalar ℓ=0 modes most sensitive to hair parameter Q, with damping weakening near the three-horizon regime.
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Perturbation Dynamics and Structure Formation in Extended Proca-Nuevo Gravity
Extended Proca-Nuevo gravity modifies the background expansion via a vector field algebraic constraint but leaves the matter growth equation identical to general relativity.
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Grey-Body Factors and Thermodynamics of Asymptotically de Sitter Black Holes in Generalized Proca Theory
Applies sixth-order WKB to compute grey-body factors for test fields on generalized Proca black holes with effective de Sitter scale, finding that scalar mass and couplings raise barriers, suppress low-frequency transmission, and affect thermodynamics.
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Noncanonical Approaches To Inflation
A review thesis covering Mukhanov parametrization, general scalar-tensor theories, and new slow-roll techniques for canonical and noncanonical inflation observables.