相关论文: Axionic instabilities and new black hole solutions

Spinning black holes can transfer a significant fraction of their energy to ultralight bosonic fields via superradiance, condensing them in a co-rotating structure or "cloud". This mechanism turns black holes into powerful particle…

One of the most compelling candidates for Dark Matter (DM) are light pseudo-scalar particles (axions), motivated by the strong CP problem and axiverse scenario in string theory. Depending on their mass and type of self-interaction, these…

We consider an augmented Einstein-Maxwell-scalar model including an axionic-type coupling between the scalar and electromagnetic field. We study dyonic black hole solutions in this model. For the canonical axionic coupling emerging from…

Axions are among the most sought-after candidates for dark matter. In the ultralight regime, they could help alleviate puzzles in small scale cosmology. Searches for a halo of axion dark matter rely on the electromagnetic response to a…

The physics of black holes can suggest new ways to test the existence of axions. Much work has been done so far to analyse the phenomenon of superradiance associated with axions in the ergoregion surrounding rotating black holes. In this…

The nature of dark matter is one of the longest-standing puzzles in science. Axions or axion-like particles are a key possibility, and arise in mechanisms to solve the strong CP problem but also in low-energy limits of string theory.…

Nonlinearities in a realistic axion field potential may play an important role in the cosmological dynamics. In this paper we use the Boltzmann code CLASS to solve the background and linear perturbations evolution of an axion field and…

In this work we construct and analyse non-perturbative stationary and axially-symmetric black hole solutions in General Relativity coupled to an electromagnetic and an axion field. The axion field is coupled to the electromagnetic field,…

Axions are hypothetical pseudoscalar particles introduced initially as a solution to the Strong CP problem in Quantum Chromodynamics (QCD), and they also arise naturally in a broad class of low-energy compactifications of string theory.…

Ultralight bosons and axion-like particles appear naturally in different scenarios and could solve some long-standing puzzles. Their detection is challenging, and all direct methods hinge on unknown couplings to the Standard Model of…

The axion is a light pseudoscalar particle postulated to solve issues with the Standard Model, including the strong CP problem and the origin of dark matter. In recent years, there has been remarkable progress in the physics of axions in…

We study the superradiant instability in scalar-tensor theories of gravitation, where matter outside a black hole provides an effective mass to the scalar degree of freedom of the gravitational sector. We discuss this effect for arbitrarily…

Contemporary attempts to explain the existence of ultra-high energy cosmic rays using plasma-based wakefield acceleration deliberately avoid non-Standard Model particle physics. However, such proposals exploit some of the most extreme…

The axion, as a leading dark matter candidate, is the target of many ongoing and proposed experimental searches based on its coupling to photons. Ultralight axions that couple to photons can also cause polarization rotation of light, which…

Light bosonic fields may suffer an instability around a rotating compact object. This process, known as superradiance, leads to the exponential amplification of the field around a black hole or neutron star, while the spin of the central…

We investigate possible end-points of the superradiant instability for a charged black hole with a reflecting mirror. By considering a fully coupled system of gravity and a charged scalar field, hairy black hole solutions are obtained. The…

New particles coupled to the Standard Model can equilibrate in stellar cores if they are sufficiently heavy and strongly coupled. In this work, we investigate the astrophysical consequences of such a scenario for massive stars by…

We find neutral and charged black branes solutions with axion fields in the context of a conformally coupled gravitational theory in four dimensions. These solutions describe AdS black branes supported by axion fields that break…

A scalar field non-minimally coupled to certain geometric [or matter] invariants which are sourced by [electro]vacuum black holes (BHs) may spontaneously grow around the latter, due to a tachyonic instability. This process is expected to…

We study the stability of static as well as of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time which possess spherical horizon topology. We observe a non-linear instability related to the condensation of a…