Time is one of the most basic physical units and probably the one we all have most experience within daily life. The most precise way of measuring time is by using so-called atomic clocks, which make use of extremely well determined quantum levels in the electron shell of atoms or ions to stabilize the “ticking”. These precision clocks have tremendous technological relevance; they constitute the backbone of our satellite-based navigation systems as well as our synchronized digital data traffic.

The Thorium nuclear clock project aims to implement a new type of clock – a nuclear clock. In contrast to electron shell levels used in atomic clocks, it uses quantum states within the atomic nucleus of Thorium-229 as a “ticking” reference. As the nucleus is a thousand times smaller than the electron shell, it reacts much less to perturbations caused by external fields or forces, so the nuclear clock is expected to be dramatically more robust than the current atomic clocks. Furthermore, the nuclear clock transition frequency is determined strongly by all fundamental forces acting inside the nucleus and hence can be used to probe these. A temporal or spatial variation of these forces could be a signature of the existence of dark matter, probably the universe’s greatest standing mystery.

Within the ERC synergy project, we will construct three complementary types of Thorium nuclear clocks and compare them amongst each other (and with conventional atomic clocks) to search for variations in the fundamental forces of nature.

Goodbye 2020

The first year of the the Thorium Nuclear Clock project has passed. And what a year it was. With the

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After a long journey, halfway across the globe, the tiny 1 mm3 Thorium doped calcium fluoride optically polished cubes have safely arrived in Japan.

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The TU Wien team cooperates with the Yoshimura group at Okayama U to excite the isomeric state of Thorium-229.

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Are you smarter than us? Please use our open data!

We have published the raw data online in the Zenodo repository, so you can check our analysis. Maybe you can do better than us?

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Phase Transition in the ‘Thorium-Isomer-Story’

Presented at the XXXVI Mazurian Lakes Conference on Physics, Piaski, Poland, September 1–7, 2019

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Ein Isomer als Uhrwerk

published in “Das Physik Journal” in June 2020

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