Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks

Abstract

We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly improve the constraints on transient variations of the fine structure constant. For example, we constrain the variation to |δα/α| < 5 × 10−17 for transients of duration 103 s. This analysis also presents a possibility to search for dark matter, the mysterious substance hypothesised to explain galaxy dynamics and other astrophysical phenomena that is thought to dominate the matter density of the universe. At the current sensitivity level, we find no evidence for dark matter in the form of topological defects (or, more generally, any macroscopic objects), and we thus place constraints on certain potential couplings between the dark matter and standard model particles, substantially improving upon the existing constraints, particularly for large (≳104 km) objects.

Demonstration of the nearly continuous operation of an171Yb optical lattice clock for half a year

“…To obtain a large amount of temporally overlapped data from laboratories worldwide, it is highly desirable that the participating clocks are capable of running continuously for a long period. The continuous operation also makes it possible to search for dark matter interactions on long timescales that could not be studied in previous experiments [75,76].…”

Precision Measurement Noise Asymmetry and Its Annual Modulation as a Dark Matter Signature

“…Note that results from the experiments in Refs. [41,42,44,46] do not apply in the considered parameter range. Shown also is the projected sensitivity for 1 year of data from an optical Sr clock, assuming σ ∼ 10 −16 s at averaging time of τ 0 = 1 s. Such clocks have been used recently for DM searches, both for "clumpy" and oscillating DM models, in Refs.…”

“…Shown also is the projected sensitivity for 1 year of data from an optical Sr clock, assuming σ ∼ 10 −16 s at averaging time of τ 0 = 1 s. Such clocks have been used recently for DM searches, both for "clumpy" and oscillating DM models, in Refs. [44,46]; details of the clock performance are given in those works (see also discussion of clock servo loop and averaging times relevant to DM searches in Refs. [42,46]).…”

“…Following these ideas, one may perform DM searches that are many orders of magnitude more sensitive than the existing constraints for certain models, and have discovery reach inaccessible by other means. Our proposal is complimentary to other ultralight DM searches, e.g., [36,[38][39][40][41][42][43][44][45][46]. The technique proves particularly appealing for the parameter space of small clumps or high number density objects, where the expected encounter rate may be high.…”

Prospects and challenges for squeezing-enhanced optical atomic clocks

“…n recent years, atomic clocks based on optical transitions 1 have achieved unprecedented levels in accuracy and stability as frequency references [2][3][4][5] . Apart from a redefinition of the SI second, this also facilitates tests of physics beyond the Standard Model [6][7][8][9] and opens up the field of relativistic geodesy [10][11][12] . For these applications, high clock stability is vital in order to reach a given frequency uncertainty in the shortest possible time.…”