Axion detection with precision frequency metrology

Abstract

We investigate a new class of galactic halo axion detection techniques based on precision frequency and phase metrology. Employing equations of axion electrodynamics, it is demonstrated how a dual mode cavity exhibits linear mode-mode coupling mediated by the axion upconversion and axion downconversion processes. The approach demonstrates phase sensitivity with an ability to detect axion phase with respect to externally pumped signals. Axion signal to phase spectral density conversion is calculated for open and closed loop detection schemes. The fundamental limits of the proposed approach come from the precision of frequency and environment control electronics, rather than fundamental thermal fluctuations allowing for table-top experiments approaching state-of-the-art cryogenic axion searches in sensitivity. Practical realisations are considered, including a TE-TM mode pair in a cylindrical cavity resonator and two orthogonally polarised modes in a Fabry-Pérot cavity.

Axion dark matter detection by superconducting resonant frequency conversion

“…Axion detection by frequency conversion in a radio frequency cavity was also briefly considered in ref. [39], but the authors did not find the same parametric enhancement we demonstrate here. 8 Fixing the geometry and other factors, scaling up both approaches in volume would decrease the relative advantage of the SRF approach.…”

Microwave cavity searches for low-frequency axion dark matter

“…However, due to the m mismatch, these modes have C 01 ¼ 0. We can attain good overlap with e.g., the TE 011 =TM 020 mode pair, but the mode frequencies are only degenerate at d=R ≃ 0.79, where d is the height of the cylinder and R is its radius [14]. For more symmetrical cavities, such as a sphere, the overlaps for degenerate modes are always zero.…”

“…By taking ω 0 ≳ L −1 ≫ m a , the response excited by this effective current is no longer in the quasistatic regime, and the absorbed power is no longer suppressed. Since the signal excitation is at a much higher frequency than the axion field, this approach is referred to as "upconversion" [14]. The idea of using an oscillating background magnetic field in axion detection experiments was first proposed in [15], but they were mostly concerned with GHz-scale axion frequencies, and did not consider the parametric scaling at low axion masses.…”

“…SRF up-conversion experiments were first proposed in [15], but as stated above, they were mainly concerned with ∼GHz axion frequencies. Up-conversion experiments for low-mass axions were considered in [14], but their sensitivity estimates are affected by some calculational errors [21], and seem to violate theoretical bounds [9].…”

New results by low momentum approximation from relativistic quantum mechanics equations and suggestion of experiments

“…A kind of DM called axion was assumed [70][71][72][73][74][75], and the attempts of detection of it were made [76]. Experimental measurements were suggested [77][78][79][80]. At least in some energy ranges, the exclusion of some of the DM that researchers had envisaged, including the axion [81][82][83], were determined.…”