Related papers: Revisiting axion dark matter with nonlinear transi…
We propose a new mechanism to produce axion dark matter from inflationary fluctuations. Quantum fluctuations during inflation are strengthened by a coupling of the axion kinetic term to the inflaton, which we parametrize as an effective…
In this note we look at the time evolution of signals in axion dark matter experiments from a quantum perspective. Our aim is not to contribute new results to the general discussion of the quantum/classical connection (which we do not) but…
The QCD axion or axion-like particles are candidates of dark matter of the universe. On the other hand, axion-like excitations exist in certain condensed matter systems, which implies that there can be interactions of dark matter particles…
Axion dark matter inevitably generates electromagnetic radiation in quantum Hall effect experiments that use strong magnetic fields. Although these emissions are very weak, we have shown using a QCD axion model that they influence the…
Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter…
Although the standard {\Lambda}CDM model describes the cosmic microwave background radiation and the large scale structure of the Universe with great success, it has some tensions with observations in the effective number of neutrino…
Existence of dark matter indicates the presence of unknown fundamental laws of nature. Ultralight axion-like particles are well-motivated dark matter candidates, emerging naturally from theories of physics at ultrahigh energies. We report…
In the scenario in which QCD axion dark matter is produced after inflation, the Universe is populated by large inhomogeneities on very small scales. Eventually, these fluctuations will collapse gravitationally to form dense axion…
Axions constitute a well-motivated dark matter candidate, and if PQ symmetry breaking occurred after inflation, it should be possible to make a clean prediction for the relation between the axion mass and the axion dark matter density. We…
The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for dark matter substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, axion perturbations…
The Peccei-Quinn mechanism presents a neat solution to the strong CP problem. As a by-product, it provides an ideal dark matter candidate, "the axion", albeit with a tiny mass. Axions therefore can act as dark radiation if excited with…
The axion is a highly motivated elementary particle which could address two fundamental questions in physics - the strong CP problem and the dark matter mystery. Experimental searches for this hypothetical particle have started to reach…
We study the stochastic axion dark matter scenario in the axion landscape, where one of the axions is light and stable and therefore explains dark matter. If the axion mass at the potential is a typical value of the curvature along the…
Axions are hypothetical particles that may explain the observed dark matter (DM) density and the non-observation of a neutron electric dipole moment. An increasing number of axion laboratory searches are underway worldwide, but these…
Cosmological moduli generically come to dominate the energy density of the early universe, and thereby trigger an early matter dominated era. Such non-standard cosmological histories are expected to have profound effects on the evolution…
Axions and axion-like particles (ALPs) are some of the most popular candidates for dark matter, with several viable production scenarios that make different predictions. In the scenario in which the axion is born after inflation, its field…
QCD axions can be a substantial part of dark matter if their mass $m_a\sim10^{-5}$eV. Since the axions were created by the misalignment mechanism, their local energy spectrum density is large. Consequently, the axion-induced atomic…
An analysis is given of interacting dark energy and dark matter where the dark energy is assumed to be an ultralight axionic field with a pseudo-Nambu-Goldstone Boson potential which is in general a superposition of $N$ number of cosine…
Axions and axion-like particles are compelling candidates for the missing dark matter of the universe. As they undergo gravitational collapse, they can form compact objects such as axion stars or even black holes. In this paper, we study…
We show that axion phenomenology may be significantly different than conventionally assumed in theories which exhibit late phase transitions (below the QCD scale). In such theories one can find multiple pseudoscalars with axion-like…