Frequency characteristics of nuclear spin oscillator with an artificial feedback toward search for ¹²⁹Xe atomic electric dipole moment

Abstract: A ¹²⁹Xe nuclearspin oscillator with an artificial feedback was constructed, and detailed studies wereconducted on its performance, focusing on the frequency stability. As a result, the majorsources of drift of the precession frequency in the present spin oscillator setup wereidentified to be drifts of a solenoid current and an environmental magnetic field. Byintroducing stabilization systems for the current and the environmental field, whichyielded improvements by one order of magnitude on the solenoid current and by a factor ofthree on the environmental field, a frequency precision of 7.9 nHz was obtained for aone-shot measurement of 3 ×10⁴s duration. We found, however, that the Allan deviationleveled off at around 30 μHz, indicating a strong need for the precisionmonitor of the experimental conditions represented by magnetometry. The frequencystability of the spin oscillator is discussed in relation to an experimental search for anelectric dipole moment of the ¹²⁹Xe atom. Graphical abstract: [Figure not available: see fulltext.]