Trapped ions ; Quantum logic ; Spectroscopy ; Titanium ion ; Far detuned ; Raman laser ; Ion loading ; Two-ion crystal preparation
Zusammenfassung
Precision spectroscopy of complex atomic and molecular ions is a valuable tool for fundamental physics and astrophysical applications. It can improve measurements of magnetic fields of stars and the search for variations of fundamental constants
using quasar spectra. Molecular ions in particular are promising candidates for measuring an electron electric dipole moment or to search for a possible variation in the electron to proton mass ratio. A complex level structure often results in the absence of closed cycling transitions, used for direct laser cooling and detection. State preparation also becomes more involved, compared to typically used atomic ions. Cooling and detection can be provided by a quantum logic approach, where a well controllable ion is co-trapped
in addition to the complex ion. Both ions interact strongly due to the Coulomb interaction. This enables sympathetic cooling. Moreover, the shared motional mode can be used as a bus to transfer information on the internal state of the complex ion to the well controllable ion, where it can be read out. In this work quantum logic was used for spectroscopy of Zeeman levels in sup.48Ti+
and for initialization of its ground state in one Zeeman level. For this a trapped ion experiment based on 40Ca+ was set up an characterized. A novel method for preparation of dual-species two-ion ion crystals has been developed and evaluated to simplify and improve current preparation strategies. It starts from a multi-ion dual-species ion chain, where one species is directly coolable and the other one is sympathetically cooled. Reduction of the number of ions is based on an iterative process, where the ion chain in split is half, each sub-chains’ constituents are detected and the chain closest to a dual-species two-ion crystal is kept, while the other one is discarded from the trap. Splitting and discarding is done by tailoring the potential landscape close to the ions
using DC potentials. The ion chains’ constituents are detected using fluorescence imaging on the directly cooled ionic species and inferring the other species’ position from that measurement. This method was applied to prepare 48Ti+-40Ca+ two-ion crystals. Utilizing quantum logic, the Zeeman level splitting of 48Ti+ is measured and state preparation is demonstrated, using a far detuned Raman laser at 532 nm. Building on these capabilities, a pathway for high precision spectroscopy, using a direct microwave interaction is presented. A far detuned Raman laser can be applied to many different ions because it is not very dependent on the ion’s level structure. As an example it can be used to investigate molecular ions, as already reported in reference [35]. The experiment presented here, aims to investigate 24MgH+ ions in the future. For that preliminary results for a convenient molecular ion preparation are showcased.
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Rechteinformation
CC BY 3.0 ; Creative Commons Attribution 3.0 License
Themenbereich der Metrologie
Zeit und Frequenz
Innovationscluster
Quantentechnologie
Geschäftsfelder
Grundlagen der Metrologie
Zitierung
Zawierucha, M. J. (2024). Quantum logic spectroscopy of titanium ions [Dissertation, Universität Hannover, 2024]. https://doi.org/10.15488/19059
