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Thorium nuclear clocks for fundamental tests of physics

Project description

The first thorium nuclear clock is a tick closer

The EU-funded ThoriumNuclearClock project will pioneer the development of the first nuclear clock, based on an energy transition in the nucleus of the thorium isotope Thorium-229. This promises to exceed the precision of today’s best atomic clocks (which make use of changes in the energy levels of atomic shell electrons) by up to an order of magnitude. The project will develop three prototype nuclear Thorium clocks using complementary approaches in trapped ions and solids and develop vacuum ultraviolet lasers to excite the thorium isotope. Comparing these clocks amongst each other and with state-of-the-art optical clocks will allow to benchmark the new frequency standard before ultimately applying it to test fundamental physics.

Objective

Th-229 has an exceptionally low-energy excited nuclear isomer state with an excitation energy of only a few electron volts, making it accessible to laser manipulation. With a predicted relative radiative linewidth of 1e-19, constructing a Thorium nuclear clock becomes possible that could rival todays most advanced optical atomic clocks.
The few-eV transition emerges from a fortunate near-degeneracy of the two lowest nuclear energy levels. However, the Coulomb and strong-force contributions to these level energies differ on the MeV level. This makes the Th-229 nuclear level structure uniquely sensitive to variations of fundamental constants and ultralight dark matter.
Very recently, the applicants have proven the long-sought existence of the low-energy isomer, determined the lifetime in different electronic environments, quantified the nuclear moments and charge radius based on the hyperfine splitting, and constrained the isomer energy. However, knowledge on the electronic and nuclear properties is still insufficient to exploit the Th-229 system for fundamental tests.
This project aims to close this gap and realize three prototype nuclear Thorium clocks using complementary approaches in trapped ions and solids. We will develop customized VUV laser systems and perform precision spectroscopy of the Th-229 nuclear transition. Comparing these clocks among each other and with state-of-the-art optical clocks will allow us to benchmark the new frequency standard before ultimately applying it to test fundamental physics.
This project requires a unique combination of experimental and theoretical expertise in atomic and nuclear physics, high precision metrology and fundamental symmetries. Furthermore, special infrastructure is required for (distributed) clock comparison, precision spectroscopy as well as processing of Th-229. The synergy team is composed to optimally respond to these challenges while being rooted in established and successful collaborations.

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Keywords

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Programme(s)

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Topic(s)

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Funding Scheme

Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.

ERC-SyG - Synergy grant

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Call for proposal

Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.

(opens in new window) ERC-2019-SyG

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Host institution

TECHNISCHE UNIVERSITAET WIEN
Net EU contribution

Net EU financial contribution. The sum of money that the participant receives, deducted by the EU contribution to its linked third party. It considers the distribution of the EU financial contribution between direct beneficiaries of the project and other types of participants, like third-party participants.

€ 3 964 291,25
Address
KARLSPLATZ 13
1040 Wien
Austria

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Region
Ostösterreich Wien Wien
Activity type
Higher or Secondary Education Establishments
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Total cost

The total costs incurred by this organisation to participate in the project, including direct and indirect costs. This amount is a subset of the overall project budget.

€ 3 964 291,25

Beneficiaries (6)

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