2024/11/09 by Aiichi Iwazaki, Iwazaki, Aiichi
Physics and Astronomy · #Atomic and Subatomic Physics Research #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.2411.06038
openalex publication_date 2024/11/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 plateau-plateau transition at low temperatures (below 100 mK) in a system with a large surface area (greater than 10-3\rm cm2) of two-dimensional electrons. By analyzing previous experiments that show saturation of the transition width ΔB as temperature and microwave frequency change, we provide evidence for the presence of axions. Notably, in most experiments without axion effects, the saturation frequency fs(T) is less than 1 GHz at temperatures of 100 mK or higher and for system sizes of 10-3\rm cm2 or smaller. Additionally, the frequency fs(T) decreases with decreasing temperature or increasing system size. However, there are experiments that show a saturation frequency fs(T)≃ 2.4GHz despite a low temperature of 35 mK and a large surface area of 6.6× 10-3\rm cm2 for the Hall bar. This identical frequency of approximately 2.4 GHz has also been observed in different plateau transitions and in Hall bars of varying sizes. These unexpected results are caused by axion microwaves. The saturation frequency fs=ma/2π of ≃ 2.4 GHz implies an axion mass of ≃ 10-5eV. By comparing the axion effect with thermal effect on the width ΔB, we have shown the dominance of the axion effect over thermal effect at low temperature less than 50mK. The dominance of the axion effect is attributed to significant absorption of axion energy, which is proportional to the square of the number of electrons involved.