Related papers: Cosmological constraints on ultra-light axion fiel…
The existence of ultralight axion (ULA) with mass $\mathcal{O}( 10^{-26}\text{eV})$ is not favored by the CMB observations in the standard $\Lambda$CDM model. We show that the inclusion of early dark energy (EDE) will lift the CMB-lockdown…
New limits on the axion-nucleon coupling over the axion mass region $10^{-24} \leq m_a \leq 5 \times 10^{-21}$ eV are derived by reanalyzing data from laboratory measurements on Lorentz and $CPT$ violation. These results establish the first…
Ultralight dark matter refers to the lightest potential dark matter candidates. We will focus on the mass range that has been studied using astrophysical and cosmological observations, corresponding to a mass $10^{-24} \, \mathrm{eV}…
The observed properties of stars and especially the neutrino signal of the supernova 1987A provide an upper limit to the axion mass, while the age and expansion rate of the universe provide a lower limit. There remains a "window of…
We search for ultra-light axions as dark matter (DM) and dark energy particle candidates, for axion masses $10^{-32}\,\mathrm{eV} \leq m_\mathrm{a} \leq 10^{-24}\,\mathrm{eV}$, by a joint analysis of cosmic microwave background (CMB) and…
Dynamical mechanisms to generate an ultralight axion of mass $\sim 10^{-21}-10^{-22}$ eV in supergravity and strings are discussed. An ultralight particle of this mass provides a candidate for dark matter that may play a role for cosmology…
We consider the hypothesis that galactic dark matter is composed of ultra-light scalar particles and use internal properties of dwarf spheroidal galaxies to establish a preferred range for the mass m of these bosonic particles. We…
Ultralight-axion (ULA) dark matter is one of the possible solutions to resolve small-scale problems, especially the core-cusp problem. This is because ULA dark matter can create a central soliton core in all dark matter haloes stemmed from…
The Ultra-Light Axion (ULA) is a dark matter candidate with mass $\mathcal{O}(10^{-22})$eV and de Broglie wavelength of order kpc. Such an axion, also called the Fuzzy Dark Matter (FDM), thermalizes via the gravitational force and forms a…
Ultra-Light Axion-like Particle (ULAP) is motivated as one of the solutions to the small scale problems in astrophysics. When such a scalar particle oscillates with an $\mathcal{O}(1)$ amplitude in a potential shallower than quadratic, it…
Motivated by tension between the predictions of ordinary cold dark matter (CDM) and observations at galactic scales, ultralight axionlike particles (ULALPs) with mass of the order $10^{-22}~{\rm eV}$ have been proposed as an alternative CDM…
We present forecasts on the detectability of Ultra-light axion-like particles (ULAP) from future 21cm radio observations around the epoch of reionization (EoR). We show that the axion as the dominant dark matter component has a significant…
We evaluate recent and upcoming low-redshift neutral hydrogen (HI) surveys as a cosmological probe of small scale structure with a goal of determining the survey criteria necessary to test ultra-light axion (ULA) dark matter models.…
Ultralight axions and other bosons are dark matter candidates present in many high energy physics theories beyond the Standard Model. In particular, the string axiverse postulates the existence of up to $\mathcal{O}(100)$ light scalar…
We present updated constraints on the parameters of an axion dark energy model, for which we took into account the properties of its characteristic potential and its full cosmological evolution. We show that the values of the axion…
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…
In an undulant universe, cosmic expansion is characterized by alternating periods of acceleration and deceleration. We examine cosmologies in which the dark-energy equation of state varies periodically with the number of e-foldings of the…
Axion-like particles (ALPs) can decay into two photons with a rest-frame frequency given by half of the ALP mass. This implies that ultra-violet searches can be used to investigate ALPs in the multi-eV mass range. We use archival data from…
The recent robust and homogeneous analysis of the world's supernova distance-redshift data, together with cosmic microwave background and baryon acoustic oscillation data, provides a powerful tool for constraining cosmological models. Here…
Ultralight axions are hypothetical scalar particles that influence the evolution of large-scale structures of the Universe. Depending on their mass, they can potentially be part of the dark matter component of the Universe as candidates…