Bumblebee gravity enhances primordial black hole abundance through three mechanisms, but the model harbors a ghost instability and a tachyonic instability that make it cosmologically unviable.
Primordial gravitational waves from spontaneous Lorentz symmetry breaking
3 Pith papers cite this work. Polarity classification is still indexing.
3
Pith papers citing it
abstract
We study the effect of Spontaneous Lorentz Symmetry Breaking (SLSB) on Primordial Gravitational Waves (PGWs) generated during inflation. The SLSB is induced by a time-like Bumblebee vector field which is non-minimally coupled to the Ricci tensor in the Friedmann-Lema\^itre-Robertson-Walker background. The power spectrum and GW amplitude are computed to investigate how Lorentz violation leaves observable imprints. We calculate the GW strain amplitude over frequencies $(10^{-10}~\mathrm{Hz}, 10^4~\mathrm{Hz})$, for a range of the dimensionless Lorentz-violating parameter, $ -10^{-3} \leq l \leq 10^{-4} $, which essentially comes from a slight sensitivity to the equation of state for dark energy. For positive $ l $ values, the amplitude of GW shows a mild suppression compared to the standard cosmological scenario $( l = 0) $. This effect could be observable with detectors like SKA, $\mu$-Ares, and BBO. Conversely, negative $ l $ values amplify the GW amplitude, enhancing detectability by both SKA, $\mu$-Ares, and BBO, as well as by THEIA and DECIGO. Notably, the GW strain amplitude increases by an order of magnitude as $ l $ moves from 0 to $ -10^{-3} $, improving prospects for detection in high-sensitivity detectors like THEIA and DECIGO.
representative citing papers
Shear viscosity adds damping to primordial gravitational waves, producing an extra red tilt for constant viscosity-to-Hubble ratio and a k-dependent blue tilt from freeze-out in the electron-photon-baryon plasma with fractional difference of order 10^{-3}.
Bumblebee theory on an FLRW background yields a cosmological model whose single free parameter is fitted to supernovae observations, producing deceleration and dark energy behaviors that are compared to Lambda-CDM.
citing papers explorer
-
Primordial black hole in Lorentz-violating theories: Insights from Bumblebee gravity
Bumblebee gravity enhances primordial black hole abundance through three mechanisms, but the model harbors a ghost instability and a tachyonic instability that make it cosmologically unviable.
-
Freeze-out and spectral running of primordial gravitational waves in viscous cosmology
Shear viscosity adds damping to primordial gravitational waves, producing an extra red tilt for constant viscosity-to-Hubble ratio and a k-dependent blue tilt from freeze-out in the electron-photon-baryon plasma with fractional difference of order 10^{-3}.
-
Cosmological implications of Bumblebee theory on an FLRW background
Bumblebee theory on an FLRW background yields a cosmological model whose single free parameter is fitted to supernovae observations, producing deceleration and dark energy behaviors that are compared to Lambda-CDM.