Observations in astronomy recommend the presence of “dark matter,” accounting for over 80% of all matter. The structure of dark matter and any prospective unknown interactions with regular matter continue to be interesting puzzles.
Given that various shifts are delicate to possible modifications of the consistent to varying degrees, contrasts of atomic clocks can be used to search for ultralight dark matter. The resulting measurement information were investigated for oscillations, the signature of ultralight dark matter. Given that no significant oscillations were found, the dark matter remained “dark”, even under closer assessment.
Huge observations suggest that dark matter, consisting of over 80% of all matter, just engages gravitationally with noticeable matter. Scientists at PTB used sensitive atomic clocks to look for proof of ultralight dark matter affecting the fine-structure consistent, but found no considerable changes, refining our understanding of its potential interactions and the stability of the continuous with time.
Comparisons in between optical clocks at PTB boost the quest to find potential interactions between ultralight dark matter and photons.
Observations in astronomy recommend the existence of “dark matter,” accounting for over 80% of all matter. The composition of dark matter and any prospective unknown interactions with routine matter continue to be interesting puzzles.
An especially promising theoretical approach suggests that dark matter might consist of particles that are extremely light and act more like waves than private particles: so-called “ultralight” dark matter. In this case, formerly undiscovered, weak interactions of dark matter with photons would result in tiny oscillations of the fine-structure constant.
The fine-structure constant is the natural constant that describes the strength of the electro-magnetic interaction. It determines the atomic energy scales and therefore influences the transition frequencies that are used as recommendations in atomic clocks. Considering that different transitions are sensitive to possible changes of the consistent to differing degrees, comparisons of atomic clocks can be used to look for ultralight dark matter. For this function, scientists at PTB have actually now used an atomic clock that is particularly sensitive to possible modifications of the fine-structure continuous in such a search.
For this purpose, this sensitive atomic clock was compared to two other atomic clocks with lower level of sensitivities in months-long measurements. The resulting measurement data were investigated for oscillations, the signature of ultralight dark matter. Because no significant oscillations were found, the dark matter stayed “dark”, even under closer examination.
Detection of the mysterious dark matter was for that reason not achieved. The absence of a signal enabled the decision of brand-new speculative ceilings on the strength of a possible coupling of ultralight matter to photons. Previous limits were enhanced by more than one order of magnitude over a vast array.
At the same time, the scientists also studied whether the fine-structure continuous may change with time, for example by increasing or reducing really slowly. Such a variation was not detected in the data. Here, existing limits were also tightened up, showing that the continuous remains consistent even over extended periods of time.
In contrast to previous clock contrasts, where each atomic clock required its own experimental system, two of the 3 atomic clocks were realized in a single speculative setup in this work. For this function, 2 various transition frequencies of a single trapped ion were utilized: The ion was questioned at the same time on both optical transitions. This is an essential action towards making optical frequency comparisons even more robust and compact– for example, for a future look for dark matter in space.
Reference: “Improved Limits on the Coupling of Ultralight Bosonic Dark Matter to Photons from Optical Atomic Clock Comparisons” by M. Filzinger, S. Dörscher, R. Lange, J. Klose, M. Steinel, E. Benkler, E. Peik, C. Lisdat and N. Huntemann, 22 June 2023, Physical Review Letters.DOI: 10.1103/ PhysRevLett.130.253001.