Dokument: A transportable strontium-88 optical lattice clock

Titel:	A transportable strontium-88 optical lattice clock
URL für Lesezeichen:	https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=72357
URN (NBN):	urn:nbn:de:hbz:061-20260223-134502-2
Kollektion:	Dissertationen
Sprache:	Englisch
Dokumententyp:	Wissenschaftliche Abschlussarbeiten » Dissertation
Medientyp:	Text
Autor:	Cong, Dongliang [Autor]
Dateien:	[Dateien anzeigen] Adobe PDF [Details] 21,80 MB in einer Datei [ZIP-Datei erzeugen] Dateien vom 19.02.2026 / geändert 19.02.2026
Beitragende:	Schiller, Stephan [Gutachter] Prof. Dr. Görlitz, Axel [Gutachter]
Dewey Dezimal-Klassifikation:	500 Naturwissenschaften und Mathematik » 530 Physik
Beschreibung:	State-of-the-art optical clocks have instabilities and systematic uncertainties better by more than two orders of magnitude than atomic clocks operating on a microwave transition frequency, which raises the discussion of the redefinition of the SI second. With the unrivaled performance, optical clocks have a wide range of potential applications, from metrology to fundamental physics, geodesy to astronomy, etc. Relativistic geodesy measurements based on frequency comparisons of optical clocks were demonstrated by several groups. In the framework of the DFG-funded research unit "Clock Metrology: A Novel Approach to TIME in Geodesy", the time comparison of optical clocks via the Atomic Clock Ensemble in Space (ACES) is proposed to demonstrate relativistic geodesy. To this end, a transportable optical clock will be integrated, operated at Geodätisches Observatorium Wettzell (GOW). In this dissertation, a transportable one-dimensional (1-D) optical lattice clock (SOC2) based on strontium-88 neutral atoms is described, which is planned to be transported to Wettzell. The clock has a compact physics package and compact, modular-designed laser systems, which make the clock easy to operate and transport. The noise contributions from various sources to the clock instability were analyzed in this dissertation. The instability of the SOC2 clock against the PTB stationary optical lattice clock (Sr3) is ∼ 5.7e−16/√τ, where τ is the averaging time in seconds. The frequency shifts due to all relevant effects were carefully characterized. The systematic uncertainty of the clock is 6.2e−17 at low atom number (∼ 240), and the main contribution is from the quadratic Zeeman shift; however, at high atom number (∼ 2250), the systematic uncertainty is 1.26e−16 with a high contribution from the lattice AC Stark shifts. The isotope shift between strontium-88 and-87 was measured by comparing the frequency of the SOC2andSr3clocks. The isotope shift is measured to be 62188134.032(35)Hz, which agrees well with the recently reported values. The isotope shift is also obtained by frequency comparison with the transportable optical lattice clock (Sr4) of PTB. This dissertation also describes direct measurements of the 88Sr frequency ratio with respect to the indium ion clock (115In+) and the electric octupole transition (E3) in the ytterbium ion clock (171Yb+) at PTB, which are, to our knowledge, reported for the first time. In order to further improve clock performance, some potential optimizations of the SOC2 clock are discussed, which could be implemented to meet the project goals. The achievable uncertainty of the SOC2 clock is less than 5.4e−18, if all effects are carefully controlled. Based on the performance described above, SOC2 will be an enabling element for time transfer between GOW and Potsdam to investigate relativistic geodesy via ACES.
Lizenz:	Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz
Fachbereich / Einrichtung:	Mathematisch- Naturwissenschaftliche Fakultät » WE Physik » Experimentalphysik
Dokument erstellt am:	23.02.2026
Dateien geändert am:	23.02.2026
Promotionsantrag am:	28.08.2025
Datum der Promotion:	01.12.2025