An experiment is measuring the amplitude of dark matter field at a certain location and at a certain time. Suppose no dark matter has been detected. Does this mean that there is no dark matter in the corresponding mass range? Not necessarily if the coherence time of the dark matter field is much longer than the duration of the experiment. It is possible, and in fact likely, that the amplitude is temporarily low due to chaotic nature of the oscillating dark matter field. This is analogous to the statistics of distribution of the amplitude of chaotic light [1].
Accounting for amplitude distribution (as opposed to assuming a fixed amplitude) shifts existing exclusion plots of the constraints on dark matter field coupling strengths [2]. This is important for correctly constraining these dark matter candidates, and should be considered for future experimental proposals and data analyses.
[1] Rodney Loudon , The Quantum Theory of Light, Oxford Science Publications (2000).
[2] arXiv:1905.13650 (2019).