Related papers: Cosmic Axion Bose-Einstein Condensation
A hypothetical particle known as the axion holds the potential to resolve both the cosmic dark matter riddle and particle physics' long-standing, strong CP dilemma. An unusually strong 21-cm absorption feature associated with the initial…
Theories on the bosonic nature of dark matter are a promising alternative to the cold dark matter model. Here we consider a dark matter halo in the state of a Bose-Einstein condensate, subject to the gravitation of a black hole. In the low…
A QCD axion with a decay constant below $ 10 ^{ 11} ~{\rm GeV} $ is a strongly-motivated extension to the Standard Model, though its relic abundance from the misalignment mechanism or decay of cosmic defects is insufficient to explain the…
We discuss current cosmological constraints on axions, as well as future sensitivities. Bounds on axion hot dark matter are discussed first, and subsequently we discuss both current and future sensitivity to models in which axions play the…
Within the model of self-gravitating Bose--Einstein condensate (BEC) dark matter (DM) it is argued that the axion-like self-interaction of ultralight bosons provides the existence of rarefied and dense phases, which are predicted earlier on…
The vorticity equation stemming from the modified Navier-Stokes equation gives a solution for a flat profile of the orbital speed of spiral galaxies. Solutions disclose existence of the Gaussian vortex clouds, the coherent vortices with…
The axion-like particles with ultralight mass ($\sim10^{-22}$eV) can be a possible candidate of dark matter, known as the fuzzy dark matter (FDM). These particles form Bose-Einstein condensate in the early Universe which can explain the…
If dark matter is mainly composed of axions, the density distribution can be nonuniformly distributed, being clumpy instead. By solving the Einstein-Klein-Gordon system of a scalar field with the potential energy density of an axionlike…
We demonstrate that dark matter axion production is enhanced through a natural and unavoidable mechanism: primordial temperature fluctuations periodically modulate the axion mass during the QCD phase transition, thereby triggering…
We show that Bose-Einstein condensate can be created in quasi-one-dimensional systems in a purely geometrical way, namely by bending or other suitable deformation of a tube.
Axion particles can form macroscopic condensates, whose size can be galactic in scale for models with very small axion masses $m\sim10^{-22}$ eV, and which are sometimes referred to under the name of Fuzzy Dark Matter. Many analyses of…
We studied the formation of compact bosonic objects through a dissipationless cooling mechanism. Implications of the existence of this mechanism are discussed, including the abundance of bosonic stars in the universe, and the possibility of…
We present a new mechanism to deplete the energy density of the QCD axion, making decay constants as high as $f_a \simeq 10^{17}\,\rm{GeV}$ viable for generic initial conditions. In our setup, the axion couples to a massless dark photon…
We show that if Dark Matter is made up of light bosons, they form a Bose-Einstein condensate in the early Universe. This in turn naturally induces a Dark Energy of approximately equal density and exerting negative pressure.This explains the…
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…
We investigate the level-crossing phenomenon in two-axion systems, where the mass eigenvalues intersect as the mass of one axion increases with the cooling of the universe. This phenomenon can significantly alter the abundance of axions in…
The EDGES Collaboration has reported an anomalously strong 21cm absorption feature corresponding to the era of first star formation, which may indirectly betray the influence of dark matter during this epoch. We demonstrate that, by virtue…
The problem of a condensate of a relativistic neutral vector boson gas constituted of particles bearing a magnetic moment is discussed. Such a vector boson system is expected to be formed either by parallel spin-pairing of neutrons in a…
We argue that the occurrence of late-time acceleration can conveniently be described by first-order general relativity covariantly coupled to fermions. Dark energy arises as a Bardeen-Cooper-Schrieffer condensate of fermions which forms in…
The Axion is a particle arising from the Peccei-Quinn solution to the strong CP problem. Peccei-Quinn symmetry breaking in the early universe could produce a large number of axions which would still be present today, making the axion a…