Related papers: Resonant Landau-Zener Conversion In Multi-Axion Sy…
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…
Axions and photons resonantly interconvert in regions where the plasma frequency approximately equals the axion mass. This process is directly analogous to an avoided level crossing in quantum mechanics, for which the celebrated…
We discuss axion dark matter detection via two mechanisms: spontaneous decays and resonant conversion in neutron star magnetospheres. For decays, we show that the brightness temperature signal, rather than flux, is a less ambiguous measure…
We investigate the prospect of an alternative laboratory-based search for the coupling of axions and axion-like particles to photons. Here, the collision of two laser beams resonantly produces axions, and a signal photon is detected after…
In the presence of an external magnetic field the axion and the photon mix. In particular, the dispersion relation of a longitudinal plasmon always crosses the dispersion relation of the axion (for small axion masses), thus leading to a…
In the strong magnetic field of a neutron star's magnetosphere, axions coupled to electromagnetism develop a nonzero probability to convert into photons. Past studies have revealed that the axion-photon conversion can be resonantly…
In the presence of a magnetic field, axions can convert into photons and vice versa. The phenomenology of the conversion is captured by a system of two coupled Klein-Gordon equations, which, assuming that the axion is relativistic, is…
The Landau-Zener transition is a fundamental concept for dynamical quantum systems and has been studied in numerous fields of physics. Here we present a classical mechanical model system exhibiting analogous behaviour using two inversely…
In particle physics, axions and axion-like particles are ubiquitous. Remarkably, ultra-light axions could constitute dark matter or dark energy. Therefore, it is important to detect axions experimentally. In the presence of a magnetic…
It was shown that the required high quality of the Peccei-Quinn (PQ) symmetry can be a natural outcome of the multiple QCD axions model. In the axiverse, a hypothetical mass mixing between the QCD axions and axion-like particles (ALPs) can…
We revisit the adiabatic conversion between the QCD axion and axion-like particle (ALP) at level crossing, which can occur in the early universe as a result of the existence of a hypothetical mass mixing. This is similar to the…
A generic low-energy prediction of string theory is the existence of a large collection of axions, commonly known as a string axiverse. Axions also have a natural cosmological production mechanism, vacuum misalignment, making them…
We introduce a novel level crossing phenomenon in the mass mixing between the QCD axions, one canonical QCD axion and one $Z_{\mathcal N}$ axion. The level crossing can take place at or slightly before the QCD phase transition critical…
Photon - axion conversions in the resonant cavity with the lowest mode are considered in detail by the Feynman diagram method. The differential cross sections are presented and numerical evaluations are given. It is shown that there is a…
Many present-day axion searches attempt to probe the mixing of axions and photons, which occurs in the presence of an external magnetic field. While this process is well-understood in a number of simple and idealized contexts, a strongly…
Axions are hypothetical particles that could address both the strong charge-parity problem in quantum chromodynamics and the enigmatic nature of dark matter. However, if axions exist, their mass remains unknown, and they are expected to…
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…
In this work, we present the refinement of axion double level crossings within the context of multi-axion mass mixing, specifically focusing on cases where the number of axions exceeds two. Our investigation reveals that double level…
We study Landau-Zener transitions between two states with the addition of a shared discretized continuum. The continuum allows for population decay from the initial state as well as indirect transitions between the two states. The…
Recently, two of the present authors showed that even when the axion momentum is much smaller than its mass, the axion can still behave like radiation if its energy density greatly exceeds the maximum potential energy set by the cosine-type…