Thorium-229 Nuclear Clock Using a VUV Frequency Comb

Erscheinungsjahr 2026
ISBN: 978-3-032-33431-2
Verlag: Springer

Buch, Englisch, 163 Seiten, Format (B × H): 155 mm x 235 mm

Reihe: Springer Theses

This thesis documents the first realization of a nuclear clock, a promising next-generation platform for precision metrology and fundamental physics, based on a 8.4 eV transition in thorium-229. Using a vacuum ultraviolet frequency comb developed by the author, the narrow 229Th nuclear clock transition in a solid-state CaF2 host crystal was studied in high resolution spectroscopy, resulting in quantum state resolution to reveal the underlying nuclear structure and establishment of a direct frequency connection between the nuclear clock and an optical atomic clock. This work marks the start of nuclear-based solid-state optical clocks and demonstrates the first comparison of nuclear and atomic clocks for fundamental physics studies. The thesis represents a remarkable convergence of precision metrology, ultrafast strong-field physics, nuclear physics, and fundamental physics. The key results that comprise this thesis are: the unprecedented precision achieved for the measurement of the narrow nuclear transition (~100 kHz linewidth, ~600 s lifetime, and absolute frequency determination to 12 significant digits); a spectrum of nuclear quadrupole splitting peaks, and the direct determination of the ratio of quadrupole moments between the ground and isomeric states; and the detailed description and characterization of the world’s unique high resolution VUV frequency comb.

Zielgruppe

Research

Autoren/Hrsg.

Zhang, Chuankun

Fachgebiete

• Naturwissenschaften Physik Quantenphysik Atom- und Molekülphysik
• Naturwissenschaften Physik Elektromagnetismus Quantenoptik, Nichtlineare Optik, Laserphysik
• Naturwissenschaften Chemie Analytische Chemie Massenspektrometrie, Spektroskopie, Spektrochemie
• Technische Wissenschaften Maschinenbau | Werkstoffkunde Technische Mechanik | Werkstoffkunde Werkstoffprüfung

Inhaltsverzeichnis

Introduction and review: A nuclear clock transition in Th.- Frequency combs in the extreme ultraviolet (XUV).- Thin-film Th targets for nuclear spectroscopy.- Direct VUV comb spectroscopy of the nuclear clock transition in a CaF2 host crystal.- Frequency characterization of a solid-state nuclear clock.- Conclusions and outlook.

Über Autor(innen)

Chuankun Zhang received his PhD in 2025 from JILA, a joint institute of NIST and the University of Colorado Boulder, under the supervision of Jun Ye. His doctoral research focused on developing a nuclear clock using a VUV frequency comb. He is currently an IQIM Postdoctoral Scholar in Andrei Faraon’s group at Caltech, where he works on quantum-network technologies using rare-earth dopants in solids.