Interactions of cosmic axions with Rydberg atoms in resonant cavities via the Primakoff process

Abstract

A quantum theoretical treatment of the interactions of cosmic axions with Rydberg atoms in resonant cavities via the Primakoff process is developed, by taking into account the finite temperature and the dissipation due to the finite damping time of the cavities. The time evolution of the number of the excited Rydberg atoms, evaluated numerically based on the theoretical formulations, enables us to obtain the detection efficiency of the axion-converted photons with a good signal-to-noise ratio. The optimum experimental setup to search for dark matter axions with Rydberg atoms is presented.PACS number͑s͒: 95.35.ϩd, 14.80.Mz, 32.80.Rm

The Rydberg-Atom-Cavity Axion Search

“…In the theoretical point of view, it is treated as a quantum system of interacting oscillators with dissipation which represent appropriately the axions, photons and atoms in the cavity. We have developed quantum theoretical calculations on the axion-photon-atom system in the resonant cavity in order to estimate precisely the detection sensitivity for dark matter axions [6]. These calculations are made by taking into account appropriately the actual experimental situations such as the motion and uniform distribution of Rydberg atoms in the incident beam as well as the spatial variation of the electric field in the cavity.…”

“…(See Ref. [6] for the details.) The signal and noise rates are calculated in terms of the atomic velocity v and the densities of the atoms in the upper state at the exit of cavityρ [a] b…”

“…The effective axion-photon coupling in the resonant cavity under the strong magnetic field is calculated from the original g aγγ coupling [6] as…”

“…We have proposed a quite efficient scheme for dark matter axion search, where Rydberg atoms are utilized to detect the axion-converted photons [6]. Then, based on this scheme we have developed ultra-sensitive Rydberg-atom-cavity detectors, CARRACK I and II (Cosmic Axion Research with Rydberg Atoms in resonant Cavities in Kyoto) [7].…”

Non-baryonic dark matter

“…The window where axions are viable DM candidates is progressively getting smaller, but still there is an acceptable range between around 10 −5 and 10 −2 eV where they pass all observational constraints and would not overclose the Universe. Fortunately, there are now two experiments [30,31] which have the experimental sensitivity of probing much of the remaining window within the next few years.…”