Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2211.15873

Spin-2 dark matter from anisotropic Universe in bigravity

Yusuke Manita·Katsuki Aoki·Tomohiro Fujita·Shinji Mukohyama
View original source ↗Read source document ↗Export metadata ↓

Abstract

Bigravity is one of the natural extensions of general relativity and contains an additional massive spin-2 field which can be a good candidate for dark matter. To discuss the production of spin-2 dark matter, we study fixed point solutions of the background equations for axisymmetric Bianchi type-I Universes in two bigravity theories without Boulware-Deser ghost, i.e., Hassan-Rosen bigravity and Minimal Theory of Bigravity. We investigate the local and global stability of the fixed points and classify them. Based on the general analysis, we propose a new scenario where spin-2 dark matter is produced by the transition from an anisotropic fixed point solution to isotropic one. The produced spin-2 dark matter can account for all or a part of dark matter and can be directly detected by laser interferometers in the same way as gravitational waves.

Explore related subjects

gr-qcastro-ph.COhep-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Yusuke Manita, Katsuki Aoki, Tomohiro Fujita, Shinji Mukohyama. 2022-11-29. Spin-2 dark matter from anisotropic Universe in bigravity. https://doi.org/10.1103/physrevd.107.104007

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Quantum Correlations of Neutrinos in the Kerr-Newman Space-time

Quantum phases establish a connection between gravitation and quantum information, offering a novel avenue for exploring the properties of space-time. In this paper, we investigate the quantum correlations (QCs) of neutrinos in the Kerr--Newman space-time for both zero- and nonzero-angular-momentum propagation. The results show that, for zero-angular-momentum propagation, the oscillation periods of the survival probability and QCs progressively decrease with propagation distance in the inward direction. In the outward direction, increasing $M$ lengthens the oscillation periods of $P_{ν_e\rightarrowν_e}$, entanglement, and the monogamy of nonlocality, whereas increasing the angular momentum $a$ or charge $Q$ shortens them. For nonzero-angular-momentum propagation, the metric parameters also generate local profile modulations through additional two-path interference terms, rather than merely rescaling the oscillation period. Furthermore, we find that, despite differences in their ranges of variation, entanglement and coherence exhibit highly consistent oscillatory behavior in both propagation cases. These findings provide a comprehensive understanding of neutrino-based relativistic quantum information.

gr-qc↗
arXiv2026

Tidal Love numbers of wormholes as black-hole mimickers

We study the dynamical scalar tidal Love numbers of wormholes that provide viable mimickers for black holes, focusing on thin-shell Schwarzschild and Damour-Solodukhin geometries. Using a matched near- and far-zone expansion, we determine their tidal response in the low-frequency regime. The presence of a long throat introduces an additional characteristic scale and naturally separates the modes into two classes. Super-throat modes probe the global wormhole geometry and are sensitive to both asymptotic regions, whereas sub-throat modes probe only one side of the wormhole and effectively perceive the throat as a black-hole horizon. We derive the scalar tidal Love numbers analytically for both classes of modes and show that their dissipative parts exhibit distinct low-frequency behavior, reflecting whether one or both potential barriers participate in the scattering process. We further find that, as the wormhole approaches the black-hole limit, the super-throat contribution becomes progressively negligible, while the sub-throat response smoothly reduces to that of a Schwarzschild black hole. These results demonstrate that the tidal response of wormholes depends crucially on whether the perturbation probes the global structure of the throat.

gr-qc↗
arXiv2026

Effective Matter Conversion in Gravitational Collapse and the Dynamical Formation of Regular Black Holes

We study inverse source reconstruction in generalized Vaidya spacetimes. A prescribed density fixes the mass and tangential pressure, while a two-sector decomposition determines a dimensionless radial balance function. We distinguish this function from a time-directed conversion rate and identify the additional null-flux information required for a covariant exchange vector. Positivity restricts the allowed target pressures: a de Sitter core cannot be represented by nonnegative sectors with nonnegative tangential equations of state. An explicit finite-density profile admits a positive vacuum-like completion, finite curvature invariants, and inner and outer trapping horizons above a calculable threshold. Its total source satisfies the null, weak, and dominant energy conditions during monotonic accretion, while the timelike convergence condition fails in the core. We check polytropic, bag-model-inspired, and condensate-inspired profiles and the corresponding cosmological reconstruction. Finally, we compute the stationary endpoint's shadow and compare its exterior deformation with published Sagittarius A* measurements. The construction establishes local curvature regularity and marginal-sphere formation, without claiming a microscopic formation mechanism, perturbative stability, or geodesic completeness.

gr-qc↗