Nuclear clock for fundamental physics

Our team is a part of the Thorium Nuclear Clock project funded by the European Research Council (ERC) Synergy Grant.

Project partners: Thorsten Schumm (TU Wien), Ekkehard Peik (PTB Braunschweig), and Peter Thirolf (LMU München). 

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 229Th as a “ticking” reference. The concept of a Thorium nuclear clock emerges from a unique property, that can be found in no other element or isotope: 229Th has an exceptionally low-energy excited nuclear isomer state with an excitation energy of only a few electron volts, making it the only nucleus accessible to laser manipulation and precision spectroscopy.

Image credit: Jeffrey C. Chase

The nuclear clock will open opportunities for highly sensitive tests of fundamental principles of physics, particularly in searches for violations of Einstein’s equivalence principle and for new particles and interactions beyond the standard model. The nuclear clock sensitivity to the variations of the electromagnetic and strong coupling constants and for corresponding  dark matter searches is expected to be several orders of magnitude larger than for atomic clocks.

The goal of the ERC synergy project is to construct three complementary types of Thorium nuclear clocks and compare them amongst each other (and with conventional atomic clocks) to search for new physics beyond the Standard Model of elementary particles. 

News: Time for a nuclear clock, UDaily article by Beth Miller.

Recent relevant publications

  • Direct detection of ultralight dark matter bound to the Sun with space quantum sensors, Yu-Dai Tsai, Joshua Eby and Marianna S. Safronova, Nature Astronomy (2022)
  • The Phenomenology of Quadratically Coupled Ultra Light Dark Matter,  Abhishek Banerjee, Gilad Perez, Marianna Safronova, Inbar Savoray, Aviv Shalit, arXiv:2211.05174 (2022).
  • New Horizons: Scalar and Vector Ultralight Dark Matter, D. Antypas et al., arXiv:2203.14915 (2022).
  • Snowmass 2021: Quantum Sensors for HEP Science – Interferometers, Mechanics, Traps, and Clocks, Oliver Buchmueller, Daniel Carney, Thomas Cecil, John Ellis, R. F. Garcia Ruiz, Andrew A. Geraci, David Hanneke, Jason Hogan, Nicholas R. Hutzler, Andrew Jayich, Shimon Kolkowitz, Gavin W. Morley, Holger Muller, Zachary Pagel, Christian Panda, Marianna S. Safronova, arXiv:2203.07250 (2022).
  • Precision calculation of hyperfine constants for extracting nuclear moments of 229Th, S.G. Porsev, M.S. Safronova, M.G. Kozlov, Phys. Rev. Lett. 127, 253001 (2021).
  • Role of triple excitations in calculating different properties of Ba+, S. G. Porsev, M. S. Safronova, Phys. Rev. A 103, 042815 (2021).
  • Low-lying energy levels of 229Th35+ and the electronic bridge process, S. G. Porsev, C. Cheung and M. S. Safronova, Quantum Sci. Technol. 6, 034014 (2021).
  • Nuclear clocks for testing fundamental physics, E. Peik, T. Schumm, M. S. Safronova, A. Pálffy, J. Weitenberg, and P. G. Thirolf, Quantum Sci. Technol. 6, 034002 (2021).
  • Probing the Relaxed Relaxion at the Luminosity and Precision Frontiers, Abhishek Banerjee, Hyungjin Kim, Oleksii Matsedonskyi, Gilad Perez, Marianna S. Safronova, J. High Energ. Phys. 2020, 153 (2020).

Supported by the European Research Council

 European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 856415)