Thomas Luschmann

Offered Bachelor’s or Master’s Theses Topics

Fabrication of a superconducting transmission line resonator in a bad-cavity limit

The rare earth spin ensembles are well established by now in the optical domain where the microwave states are used as an intermediate state to extend the storage time [1]. Number of purely microwave manipulations by spin ensembles is very limited and is bound to coupling of spin ensembles to microwave resonating structures [2], which allows amplifying the microwave signal and enhancing the interaction between the ions and the microwave field. The main disadvantage of using these resonating structures is their fixed frequencies and very small tuning range. Typically fabricated in a coplanar design, the superconducting resonators create strongly inhomogeneous distribution of the field within the spin ensemble, which results into largely detuned Rabi frequencies experienced by the spins. Aim of this project is to fabricate novel design of microwave transmission line resonator, which would work in a bad-cavity regime and will thus allow to couple to rare-earth spins at a larger badwidth. This will allow realizing various spin manipulation schemes, which involve more than two energy levels (beyond Hahn-echo) and thus deploy complex spin-manipulation techniques. We are looking for a highly motivated master student joining this project. Within the project, you will gain hands-on experience on design and fabrication of superconducting microwave structures. You will design and fabricate superconducting resonating structure, which will then be tested at cryogenic conditions when coupled to rare earth spins ensembles. [1] Kinos, A. et al. Roadmap for Rare-earth Quantum Computing. arXiv 2103.15743 (2021). [2] Ranjan, V. et al. Multimode Storage of Quantum Microwave Fields in Electron Spins over 100 ms. https://link.aps.org/doi/10.1103/PhysRevLett.125.210505 (2021).

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Rudolf Gross