分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The cosmological axions/axion-like particles can compose a significant part of dark matter, however the uncertainty of their mass is large. Here we propose to search the axions using a cylindrical capacitor, in which the static electric field converts dark matter axions into an oscillating magnetic field. Using a static electric field can greatly reduce the magnetic field background compared to using the $\vec B$ field in which the small fluctuations could be hard to annihilate. A cylindrical setup shields the electric field to the laboratory as well as encompasses the axion induced magnetic field within the capacitor, and results in an increased magnetic field strength. The induced oscillating magnetic field then can be picked up by a very sensitive magnetometer. In addition, adding a superconductor ring-coil system into the induced magnetic field region can further boost the sensitivity and maintain the axion dark matter inherent bandwidth. This proposed setup is capable of a wide mass range search.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The characteristic axion couplings could be generated via effective couplings between the Standard Model (SM) fermions to a pseudo-Goldstone from a high-scale $U(1)$ Peccei-Quinn (PQ) symmetry breaking. Assuming that the UV-induced effective operators generate necessary couplings before the PQ symmetry breaking, and any low-scale couplings to the SM are restricted to the Yukawa sector, three minimal natural scenarios can be formulated, which provides a connection between the QCD-axions and mediators at the GUT/string scales. We find that the PQ symmetry breaking scale could be about $10^{15}$ GeV, higher than the classical QCD dark matter axion window but possible if the anthropic window is considered. We also propose an experiment to probe such scenarios. If the dark matter axion is discovered, they might suggest that we live in an atypical Hubble volume.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We propose a dual-path interferometry amplification configuration in the cavity axion dark matter searches. We show quantum-mechanically that, in a low temperature cavity permeated by a magnetic field, the single axion-photon conversion rate is enhanced by the cavity quality factor $Q$, and quantitatively larger than the classical result by a factor $\pi/2$. Under modern cryogenic conditions, thermal photons in the cavity are negligible, thus the axion cavity can be considered as a quantum device emitting single-photons with temporal separations. This differs from the classical picture in which axions transition in batches and the converted energy accumulates in the electromagnetic field inside the cavity. It reveals a possibility for the axion cavity experiment to handle the signal sensitivity at the quantum level, e.g. cross-power and second order correlation measurements. The correlation of photon field quadratures in the amplification chain, within current technology, enhances the signal-to-noise ratio up to two orders of magnitude or one order of magnitude compared with single-path amplification scheme based on high electronic mobility transistor amplifier or Josephson Parametric Amplifiers (JPA), respectively. Especially, it is useful to combine the dual-path interferometry scheme with other techniques, e.g. JPAs, to overcome the inevitable microwave signals insertion loss (normally it is $\sim-3\,$dB) in the channels between the cavity and the quantum-limited amplifiers. This enhancement would greatly reduce the signal scanning time and improve the sensitivity of the axion-photon coupling. In addition, the second order correlation function measurement in the due path scheme can provide an additional verification that if the candidate signals are axion converted or other noises.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We propose a dual-path interferometry amplification configuration in the cavity axion dark matter searches. We show quantum-mechanically that, in a low temperature cavity permeated by a magnetic field, the single axion-photon conversion rate is enhanced by the cavity quality factor $Q$, and quantitatively larger than the classical result by a factor $\pi/2$. Under modern cryogenic conditions, thermal photons in the cavity are negligible, thus the axion cavity can be considered as a quantum device emitting single-photons with temporal separations. This differs from the classical picture in which axions transition in batches and the converted energy accumulates in the electromagnetic field inside the cavity. It reveals a possibility for the axion cavity experiment to handle the signal sensitivity at the quantum level, e.g. cross-power and second order correlation measurements. The correlation of photon field quadratures in the amplification chain, within current technology, enhances the signal-to-noise ratio up to two orders of magnitude or one order of magnitude compared with single-path amplification scheme based on high electronic mobility transistor amplifier or Josephson Parametric Amplifiers (JPA), respectively. Especially, it is useful to combine the dual-path interferometry scheme with other techniques, e.g. JPAs, to overcome the inevitable microwave signals insertion loss (normally it is $\sim-3\,$dB) in the channels between the cavity and the quantum-limited amplifiers. This enhancement would greatly reduce the signal scanning time and improve the sensitivity of the axion-photon coupling. In addition, the second order correlation function measurement in the due path scheme can provide an additional verification that if the candidate signals are axion converted or other noises.
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