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Technical Physics

Prof. Rudolf Gross, Prof. Stefan Filipp

Research Field

The research activities of the Walther-Meißner-Institute are focused on low temperature solid-state and condensed matter physics. The research program is devoted to both fundamental and applied research and also addresses materials science, thin film and nanotechnology aspects. With respect to basic research the main focus of the WMI is on

  • superconductivity and superfluidity,
  • magnetism, spin transport, and spin caloritronics,
  • quantum phenomena in mesoscopic systems and nanostructures,
  • quantum technology and quantum computing,
  • and the general properties of metallic systems at low and very low temperatures.

The WMI also conducts applied research in the fields of

  • solid-state quantum information processing systems,
  • superconducting and spintronic devices,
  • oxide electronics,
  • multi-functional and multiferroic materials,
  • and the development of low and ultra low temperature systems and techniques.

With respect to materials science, thin film and nanotechnology the research program is focused on

  • the synthesis of superconducting and magnetic materials,,
  • the single crystal growth of oxide materials,
  • the thin film technology of complex oxide heterostructures including multi-functional and multiferroic material systems,
  • the fabrication of superconducting, magnetic, and hybrid nanostructures,
  • and the growth of self-organized molecular ad-layers.

The WMI also develops and operates systems and techniques for low and ultra-low temperature experiments. A recent development are dry mK-systems that can be operated without liquid helium by using a pulse-tube refrigerator for precooling. Meanwhile, these systems have been successfully commercialized by the company VeriCold Technologies GmbH at Ismaning, Germany, which meanwhile has been acquired by Oxford Instruments. As further typical examples we mention a nuclear demagnetization cryostat for temperature down to below 100µK, or very flexible dilution refrigerator inserts for temperatures down to about 20mK fitting into a 2inch bore. These systems have been engineered and fabricated at the WMI. Within the last years, several dilution refrigerators have been provided to other research groups for various low temperature experiments. The WMI also operates a helium liquifier with a capacity of more than 150.000 liters per year and supplies both Munich universities with liquid helium. To optimize the transfer of liquid helium into transport containers the WMI has developed a pumping system for liquid helium that is commercialized in collaboration with a company.

Address/Contact

Walther-Meißner-Straße 8
85748 Garching b. München
+49 (89) 289 - 14202
Fax: +49 (89) 289 - 14206

Members of the Research Group

Professors

Office

Scientists

Other Staff

Teaching

Course with Participations of Group Members

Titel und Modulzuordnung
ArtSWSDozent(en)Termine
Applied Superconductivity 1: from Josephson Effects to RSFQ Logic
LV-Unterlagen
Zuordnung zu Modulen:
VO 2 Fedorov, K. Mi, 14:15–15:45, WMI 143
Magnetism
eLearning-Kurs LV-Unterlagen
Zuordnung zu Modulen:
VO 2 Kukharchyk, N. Di, 14:00–15:30, WMI 143
QST Experiment: Quantum Hardware
Zuordnung zu Modulen:
VO 4 Filipp, S. Do, 16:00–18:00, PH HS1
Fr, 08:00–10:00, PH HS1
Quantum Sensing
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Brandt, M. Bucher, D. Hübl, H. Mi, 10:00–12:00, ZNN 0.001
Superconductivity and Low Temperature Physics 1
eLearning-Kurs LV-Unterlagen
Zuordnung zu Modulen:
VO 2 Gross, R. Do, 12:00–14:00, PH HS3
Fortschritte in der Festkörperphysik
LV-Unterlagen
Zuordnung zu Modulen:
PS 2 Gross, R. Di, 10:15–11:30, WMI 143
Quantum Entrepreneurship Laboratory
Zuordnung zu Modulen:
HS 2 Filipp, S. Mendl, C. Pollmann, F.
Mitwirkende: Cerda Sevilla, M.Trummer, C.
Spin Currents and Skyrmionics
eLearning-Kurs
Zuordnung zu Modulen:
PS 2 Hübl, H.
Mitwirkende: Althammer, M.Geprägs, S.Opel, M.
Do, 14:00–15:30, WMI 039
Supraleitende Quantenschaltkreise
LV-Unterlagen virtueller Hörsaal
Zuordnung zu Modulen:
PS 2 Deppe, F. Filipp, S.
Leitung/Koordination: Gross, R.
Mitwirkende: Fedorov, K.Marx, A.
Termine in Gruppen
Topical Issues in Magneto- and Spin Electronics
LV-Unterlagen
Zuordnung zu Modulen:
HS 2 Brandt, M. Hübl, H.
Mitwirkende: Althammer, M.Geprägs, S.
Mi, 11:30–13:00, WSI S101
Exercise to Applied Superconductivity 1: from Josephson Effects to RSFQ Logic
Zuordnung zu Modulen:
UE 2
Leitung/Koordination: Fedorov, K.
Termine in Gruppen
Exercise to Magnetism
eLearning-Kurs LV-Unterlagen
Zuordnung zu Modulen:
UE 1 Kukharchyk, N. Termine in Gruppen
Exercise to QST Experiment: Quantum Hardware
Zuordnung zu Modulen:
UE 2 Haslbeck, F. Wallner, F.
Leitung/Koordination: Filipp, S.
Termine in Gruppen
Übung zu Supraleitung und Tieftemperaturphysik 1
eLearning-Kurs LV-Unterlagen
Zuordnung zu Modulen:
UE 2 Gross, R. Termine in Gruppen
Festkörperkolloquium
aktuelle Informationen
Zuordnung zu Modulen:
KO 2 Gross, R. Do, 17:00–19:00, PH HS3
sowie einzelne oder verschobene Termine
FOPRA Experiment 104: The Josephson Parametric Amplifier (JPA) (QST-EX)
LV-Unterlagen
Zuordnung zu Modulen:
PR 1 Honasoge, K. Kronowetter, F.
Leitung/Koordination: Gross, R.
FOPRA Experiment 108: Qubit Control and Characterization for Superconducting Quantum Processors (AEP, KM, QST-EX)
LV-Unterlagen
Zuordnung zu Modulen:
PR 1 Tsitsilin, I. Wallner, F.
Leitung/Koordination: Filipp, S.
FOPRA Experiment 16: Josephson Effects in Superconductors (AEP, KM, QST-EX)
LV-Unterlagen aktuelle Informationen
Zuordnung zu Modulen:
PR 1 Honasoge, K. Kronowetter, F. Nojiri, Y.
Leitung/Koordination: Gross, R.
Journal Club on Quantum Systems
Zuordnung zu Modulen:
SE 2 Filipp, S. Mi, 09:00–11:00, WMI 143
Repetitorium zu Aktuelle Themen der Magneto- und Spinelektronik
Zuordnung zu Modulen:
RE 2
Leitung/Koordination: Hübl, H.
Repetitorium zu Fortschritte in der Festkörperphysik
Zuordnung zu Modulen:
RE 2
Leitung/Koordination: Gross, R.
Repetitorium zu Quanten-Entrepreneurship-Labor
Zuordnung zu Modulen:
RE 2
Leitung/Koordination: Filipp, S.
Repetitorium zu Spin-Ströme und Skyrmionik
Zuordnung zu Modulen:
RE 2
Leitung/Koordination: Hübl, H.
Repetitorium zu Supraleitende Quantenschaltkreise
Zuordnung zu Modulen:
RE 2
Leitung/Koordination: Gross, R.
Walther-Meißner-Seminar on Topical Problems of Low Temperature Physics
aktuelle Informationen
Zuordnung zu Modulen:
SE 2 Filipp, S. Gross, R. Termine in Gruppen

Offers for Theses in the Group

Fabrication of a superconducting coplanar transmission line for efficient coupling to rare earth spin ensembles
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, which will allow for homogeneous distribution of the microwave field within the excited rare-earth spin ensemble, and at the same time, will not be bound to a specific frequency. 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 transmission line, 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
Fabrication of a superconducting coplanar transmission line for efficient coupling to rare earth spin ensembles
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, which will allow for homogeneous distribution of the microwave field within the excited rare-earth spin ensemble, and at the same time, will not be bound to a specific frequency. 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 transmission line, 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 Condensed Matter Physics
Supervisor: Rudolf Gross
Fabrication of a superconducting coplanar transmission line for efficient coupling to rare earth spin ensembles
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, which will allow for homogeneous distribution of the microwave field within the excited rare-earth spin ensemble, and at the same time, will not be bound to a specific frequency. 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 transmission line, 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 Quantum Science & Technology
Supervisor: Rudolf Gross
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 Condensed Matter Physics
Supervisor: Rudolf Gross
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 Quantum Science & Technology
Supervisor: Rudolf Gross
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
Fabrication of low-loss Josephson parametric devices
Superconducting Josephson devices represent one of the leading hardware platforms of modern quantum information processing. In particular, these devices often employ nonlinear parametric effects for tunable coupling schemes or quantum-limited amplification. Such effects can be also used in a multitude of quantum communication & sensing protocols. In this context, a particular challenge arises due to the fundamental requirement for minimizing losses in superconducting systems in order to preserve the fragile quantum nature of related microwave states. To this end, one needs to develop advanced routines for fabrication of low-loss Josephson parametric amplifiers & parametric couplers by exploring various surface treatment approaches or studying novel superconducting materials. The low-loss Josephson devices are to be used in our ongoing experiments towards experimental investigation of particular novel concepts, such as the quantum radar or remote entanglement distribution protocols. This master thesis will involve designing superconducting parametric circuits, cleanroom fabrication, and characterization measurements of fabricated devices with an aim to employ these in microwave quantum communication & sensing experiments.
suitable as
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Rudolf Gross
Fabrication of low-loss Josephson parametric devices
Superconducting Josephson devices represent one of the leading hardware platforms of modern quantum information processing. In particular, these devices often employ nonlinear parametric effects for tunable coupling schemes or quantum-limited amplification. Such effects can be also used in a multitude of quantum communication & sensing protocols. In this context, a particular challenge arises due to the fundamental requirement for minimizing losses in superconducting systems in order to preserve the fragile quantum nature of related microwave states. To this end, one needs to develop advanced routines for fabrication of low-loss Josephson parametric amplifiers & parametric couplers by exploring various surface treatment approaches or studying novel superconducting materials. The low-loss Josephson devices are to be used in our ongoing experiments towards experimental investigation of particular novel concepts, such as the quantum radar or remote entanglement distribution protocols. This master thesis will involve designing superconducting parametric circuits, cleanroom fabrication, and characterization measurements of fabricated devices with an aim to employ these in microwave quantum communication & sensing experiments.
suitable as
  • Master’s Thesis Condensed Matter Physics
Supervisor: Rudolf Gross
Fabrication of low-loss Josephson parametric devices
Superconducting Josephson devices represent one of the leading hardware platforms of modern quantum information processing. In particular, these devices often employ nonlinear parametric effects for tunable coupling schemes or quantum-limited amplification. Such effects can be also used in a multitude of quantum communication & sensing protocols. In this context, a particular challenge arises due to the fundamental requirement for minimizing losses in superconducting systems in order to preserve the fragile quantum nature of related microwave states. To this end, one needs to develop advanced routines for fabrication of low-loss Josephson parametric amplifiers & parametric couplers by exploring various surface treatment approaches or studying novel superconducting materials. The low-loss Josephson devices are to be used in our ongoing experiments towards experimental investigation of particular novel concepts, such as the quantum radar or remote entanglement distribution protocols. This master thesis will involve designing superconducting parametric circuits, cleanroom fabrication, and characterization measurements of fabricated devices with an aim to employ these in microwave quantum communication & sensing experiments.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Hybrid quantum teleportation
Microwave quantum communication is a novel field of science and technology, where one exploits quantum properties of propagating microwave signals to achieve quantum advantage in various communication scenarios. Here, a particularly important protocol is quantum teleportation, where one bypasses fundamental limitations on fidelity of transferred quantum states by exploiting shared entanglement. In this context, an open challenge is teleportation of the most exotic, non-Gaussian, quantum states, such as Fock or Schrödinger cat states, with the help of Gaussian entangled states. In theory, this problem can be addressed by using non-deterministic approaches or incorporating non-Gaussian operations in the teleportation protocol. This master thesis will focus on a theory analysis & numerical simulation of quantum microwave teleportation of non-Gaussian quantum states. Later stages of this master project may include experimental investigation of proof-of-principle hybrid quantum teleportation protocols based on superconducting quantum circuits in the cryogenic environment.
suitable as
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Rudolf Gross
Hybrid quantum teleportation
Microwave quantum communication is a novel field of science and technology, where one exploits quantum properties of propagating microwave signals to achieve quantum advantage in various communication scenarios. Here, a particularly important protocol is quantum teleportation, where one bypasses fundamental limitations on fidelity of transferred quantum states by exploiting shared entanglement. In this context, an open challenge is teleportation of the most exotic, non-Gaussian, quantum states, such as Fock or Schrödinger cat states, with the help of Gaussian entangled states. In theory, this problem can be addressed by using non-deterministic approaches or incorporating non-Gaussian operations in the teleportation protocol. This master thesis will focus on a theory analysis & numerical simulation of quantum microwave teleportation of non-Gaussian quantum states. Later stages of this master project may include experimental investigation of proof-of-principle hybrid quantum teleportation protocols based on superconducting quantum circuits in the cryogenic environment.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Lateral angular momentum transport by phonons
In a solid-state system, spin angular momentum is mediated by various (quasi-)particles. Among these excitations are phonons, which can carry angular momentum over mm distances. Most importantly, exchange of spin angular momentum from these crystal lattice vibrations to excitations of the magnetic lattice is possible via magneto-elastic coupling effects. This unlocks novel means for coherent and incoherent spin transport concepts without moving charges. Your thesis will be dedicated in assessing the realization of incoherent angular momentum transfer in nanostructured systems. In your thesis you will work on an all-electrical injection and detection scheme to access incoherent angular momentum transfer. You will use state-of-the-art nanofabrication techniques using electron beam lithography and thin film deposition machines for the realization of magnon-phonon hybrid devices. You will also gain experience in cryogenic magnetotransport techniques. You will develop automated evaluation tools and work on modelling the observed phenomena.
suitable as
  • Master’s Thesis Condensed Matter Physics
Supervisor: Rudolf Gross
Magnetic resonance spectroscopy in two dimensional ferromagnets
Dimensionality crucially influences the properties of materials. Two-dimensional (2d) van der Waals materials in the monolayer limit are presently heavily investigated. Within this class of materials systems with magnetic order exist, yet only limited insights have been obtained with respect to their magnetic excitation properties. A major experimental challenge is the small volume and thus low number of spins in these systems. Thus, high sensitivity techniques and large filling factors are key for successful studies of these materials. The goal of this thesis is to use planar superconducting resonators in combination with 2d van der Waals ferromagnets to study magnetic excitations at low temperatures by microwave spectroscopy. You will work on implementing the microwave-based spectroscopy of magnetic excitations in 2d systems. You will use state-of-the-art nanofabrication techniques like electron beam lithography and thin film deposition machines for the superconducting resonators. You will also gain experience in cryogenic microwave spectroscopy utilizing vector network analyzing techniques. Another important aspect will be the development of a quantitative model to illuminate the underlying physics of the magnetic excitations.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Magnon-mechanics in suspended nano-structures
Nano-mechanical strings are archetypical harmonic oscillators and can be straightforwardly integrated with other nanoscale systems. For example, the field of nano-electromechanics studies the coupling of nano-strings to microwave circuits, which resulted in the creation of mechanical quantum states and concepts for microwave to optics conversion. Here, we plan to investigate an alternative hybrid system based on ferromagnetic nanostructures integrated with nano-strings or nano-mechanical platforms. These hybrid devices aim at the efficient conversion between phonons and magnons with the potential to interact with light and are thus ideal candidates for conversion applications. We are looking for a motivated master student for a nano-mechanical master thesis in the context of magnon-phonon interaction. The goal of your project is to investigate the static and dynamic interplay between the mechanical and magnetic properties of a nano-mechanical system sharing an interface with a magnetic layer. In your thesis project, you will fabricate freely suspended nanostructures based on magnetic thin films using state-of-the-art nano-lithography and deposition techniques. Further, you will probe the mechanical response of the nano-structures using optical interferometry while exciting the magnetization dynamics of the magnetic system.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Magnon transport in laterally confined magnetic insulators
In antiferromagnetic insulators, we obtain two magnon modes with opposite spin chirality due to the two opposing magnetic sublattices. In this way, magnon transport in antiferromagnetic insulators can be considered as the magnonic equivalent of electronic spin transport in semiconductors and the properties can be mapped onto a magnonic pseudospin. At present, most experiments rely on extended epitaxial thin films of antiferromagnetic insulators. Your thesis will be dedicated to confine the lateral dimensions of the magnon transport channel. By conducting all-electrical magnon transport experiments, you will then determine the role of lateral confinement in such measurement schemes. You are interested in providing novel insights into pseudospin properties in antiferromagnetic insulators and provide a spark for theoretical descriptions. In order to answer questions regarding magnon transport in magnetic insulators, your thesis will contain aspects of the fabrication of nano-scale devices using electron beam lithography as well as ultra-sensitive low-noise electronic measurements at high magnetic fields in a cryogenic environment.
suitable as
  • Master’s Thesis Condensed Matter Physics
Supervisor: Rudolf Gross
Microwave cryptography with propagating quantum tokens
Quantum cryptography based on continuous-variables is a rapidly growing field of fundamental and applied research. It deals with various topics regarding fundamental limits on data communication & security. In particular, the microwave branch of quantum cryptography demonstrates a large potential for near term applications due to its natural frequency compatibility with the upcoming 5G and future 6G networks. In this context, we plan to investigate microwave photonic states, quantum tokens, which can be used for unconditionally secure storage and transfer of classical information. This security properties are provided by a peculiar combination of the quantum no-cloning theorem and vacuum squeezing phenomenon. The latter effect can be routinely achieved in the microwave regime with superconducting Josephson parametric amplifiers, which we plan to use for experimental generation & investigation of quantum token states. This master thesis will focus on developing numerical & experimental tools for the ongoing microwave quantum cryptography experiments. This includes programming various elements of FPGA data processing routines, performing cryogenic measurements with propagating microwaves, and analyzing measurement data for quantifying quantum correlations & unconditional security in propagating quantum token states.
suitable as
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Rudolf Gross
Microwave cryptography with propagating quantum tokens
Quantum cryptography based on continuous-variables is a rapidly growing field of fundamental and applied research. It deals with various topics regarding fundamental limits on data communication & security. In particular, the microwave branch of quantum cryptography demonstrates a large potential for near term applications due to its natural frequency compatibility with the upcoming 5G and future 6G networks. In this context, we plan to investigate microwave photonic states, quantum tokens, which can be used for unconditionally secure storage and transfer of classical information. This security properties are provided by a peculiar combination of the quantum no-cloning theorem and vacuum squeezing phenomenon. The latter effect can be routinely achieved in the microwave regime with superconducting Josephson parametric amplifiers, which we plan to use for experimental generation & investigation of quantum token states. This master thesis will focus on developing numerical & experimental tools for the ongoing microwave quantum cryptography experiments. This includes programming various elements of FPGA data processing routines, performing cryogenic measurements with propagating microwaves, and analyzing measurement data for quantifying quantum correlations & unconditional security in propagating quantum token states.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Nano-electromechanics in the non-linear regime
Circuit nano-electromechanics is a new field in the overlap region between solid-state physics and quantum optics with the aim of probing quantum mechanics in macroscopic mechanical structures. We employ superconducting circuits to address fundamental questions like the preparation of phonon number states in the vibrational mode and the conversion of quantum states between the mechanical element and the microwave domain. The initial successful experiments of the group include hybrid devices based on nano-string resonators inductively coupled to frequency tunable microwave resonators. This setting allows to explore large optomechanical single photon rates, enables intrinsic amplification schemes, and hereby allows to access a new regime of light matter coupling. The goal of your thesis is the development and fabrication of hybrid devices based on frequency tunable superconducting microwave resonators with integrated nanomechanical string-resonators as well as their spectroscopy. This includes the design and fabrication of these devices, where you will use state-of-the-art simulation and nano-fabrication techniques. The second main aspect of your thesis is their investigation using highly sensitive microwave spectroscopy techniques in a low-temperature environment.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Non-reciprocal magnonic devices

Spin waves (magnons) are the quantized excitations of the magnetic lattice in solid state systems. The field of magnonics is exploring concepts to use these magnons for information transport and processing. Of particular interest is to achieve non-reciprocity for opposite spin wave propagation directions, which can be realized in hybrid structures of a periodic artificial magnetic array on top of a magnonic waveguide. These systems would be potential candidates for compact microwave directional couplers and circulators operational at low temperatures. The goal of this thesis is to develop and optimize such nonreciprocal devices based on periodic magnetic arrays. This implementation is a first step towards compact low temperature microwave circuits relevant for superconducting quantum circuits.

You are a resourceful master student willing to contribute with your thesis towards the successful implementation of nonreciprocal microwave devices at cryogenic temperatures. You will use state-of-the-art nanofabrication techniques using electron beam lithography and thin film deposition machines to design your hybrid systems. You will also gain experience in cryogenic microwave spectroscopy utilizing vector network analyzing techniques. Utilizing a combination of numerical and analytical models, you will drive the optimization of such hybrid devices.

suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Optical detection of magnetization dynamics at low temperatures
Utilizing magneto-optical effects enables the investigation of excitations in magnetic systems like magnons or spin waves down to the sub-micrometer scale. In this way, one can probe spin wave propagation in micro-patterned ferromagnetic materials, which is highly relevant for spintronic applications as well the investigation of tailored quantum systems. Especially at low temperatures, novel magnetic phases exist with intriguing magnetization dynamic properties. The goal of this thesis is the optical investigation of spatially resolved magnetization dynamics in spintronic devices as well as hybrid quantum systems at cryogenic temperatures. We are searching for a highly motivated master student to start the experiments on optically detected magnetization dynamics at cryogenic temperatures. You will improve the optical setup used for the detection of magnetization dynamics to increase the sensitivity. In addition, you will work with state-of-the-art microwave equipment to drive the magnetization dynamics in spintronic devices and hybrid systems. After assessing the performance of the setup with state-of-the-art magnetic systems, you will work in the clean room facilities of our institute to carry out the microfabrication steps to define your own spintronic devices or hybrid systems.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Optical readout of spin ensembles
Electron spin resonance provides means to very sensitive magnetic field sensors. At present charged nitrogen vacancies in diamond provide unique properties such as optical readout of the electron spin state and spin coherence above room temperature. This allows to use this system for magnetic field sensing applications. You will work on implementing an experimental platform for optical readout and microwave manipulation of electron spins in nitrogen vacancy centers in your thesis. For the setup you will use optical detection schemes and laser illumination. In addition, you employ microwave signals to manipulate the spin state in the nitrogen vacancy center. You will then use calibration measurements to quantify the performance of the new setup.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Rudolf Gross
Piezoelectric response of AlN thin films
Micro electro-mechanical systems are an important building block for miniaturized sensor and actuator applications. This requires thin films with piezoelectric properties. Among them, AlN provides unique advantages for integration into Si-based electronics and optoelectronics. Doping with rare earth elements leads to a distortion of the hexagonal lattice and can even enhance the piezoelectric response. The goal of this thesis is the optimization of AlN sputter deposited thin films in regards to their piezoelectric properties. You will investigate the role of doping on the piezoelectric properties. In your thesis, you will use state-of-the-art thin film sputter deposition to optimize the growth by tuning the deposition conditions. You then will employ structural analysis using X-ray diffraction to investigate the epitaxial properties of the deposited thin films. In addition, you will characterize the piezoelectric properties and ferroelectric domain structure by piezo-force microscopy techniques.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Rudolf Gross
Quantum acoustics with mechanical nanostrings

The field of quantum acoustics aims to investigate quantum mechanical effects in acoustic resonator structures. Combined with e.g. optical and / or superconducting circuits, this offers the possibility to create quantum hybrid systems, which are discussed in the context of storing and converting quantum states. In this project, we shall investigate one of the building blocks, i.e. a mechanical nanostring resonator with a superconducting thin film. With your help, we aim to develop and optimize nanostring resonators operating in the GHz frequency range with high quality factors and test these devices at moderately low (3-10K) temperatures.

 

Your bachelor thesis will bring you in touch with state-of-the-art nanofabrication technology and introduce you to microwave spectroscopy tools like vector network analyzers, as well as optical measurements in a cryogenic environment. Careful data analysis of the laser interferometry data of these resonators combined with modeling will put you in the position, to make a meaningful contribution to the creation of quantum hybrid systems.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Rudolf Gross
Quench protection for a superconducting magnet
The generation of magnetic fields with electrical currents is deployed in multiple systems, such as generators, motors, MRI systems, up to particle accelerators and fusion reactors. In laboratory, we use superconducting magnets, which allow to generate magnetic fields at cryogenic conditions to manipulate the electronic spin transitions of paramagnetic ions. However, superconducting magnets may undergo a spontaneous transition into the normal state - a so-called quenching process. Such event would result in the generation of a large thermal energy, which is increasing with the size of the magnet. Such amount of thermal energy is enormous for a magnet placed in a cryostat below 4K. Solutions allowing to protect the magnet in case of a quench are called quench protection circuits. In this project, you are offered to develop a quench protection circuit for an existing superconducting magnet. During the project you will learn about cryogenics, the generation of magnetic fields, superconducting magnets and design of electrical circuits. We are looking for a highly motivated bachelor student joining this project. During this project you will work in an international team at Walther-Meißner-Institute.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Rudolf Gross
Remote entanglement of superconducting qubits
Quantum computing represents a promising information processing paradigm exploiting quantum properties, such as superposition and entanglement. The latter entity is crucial for achieving quantum advantage in scalable quantum information processing with distributed quantum computers, including those built with superconducting qubits. Here, an important task is to study how quantum entanglement can be distributed between remote superconducting qubits. To this end, we plan to exploit propagating two-mode squeezed states as a carrier of quantum entanglement. We intend to analyze their interactions with remote superconducting quantum bits in theory & verify our findings in experiments. This master thesis will first focus on theory & numerical simulations of remote entanglement of superconducting qubits with propagating squeezed light. Later project stages may also include cryogenic experiments with superconducting transmon qubits & Josephson parametric amplifiers towards verifying novel concepts of remote entanglement.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Remote entanglement of superconducting qubits
Quantum computing represents a promising information processing paradigm exploiting quantum properties, such as superposition and entanglement. The latter entity is crucial for achieving quantum advantage in scalable quantum information processing with distributed quantum computers, including those built with superconducting qubits. Here, an important task is to study how quantum entanglement can be distributed between remote superconducting qubits. To this end, we plan to exploit propagating two-mode squeezed states as a carrier of quantum entanglement. We intend to analyze their interactions with remote superconducting quantum bits in theory & verify our findings in experiments. This master thesis will first focus on theory & numerical simulations of remote entanglement of superconducting qubits with propagating squeezed light. Later project stages may also include cryogenic experiments with superconducting transmon qubits & Josephson parametric amplifiers towards verifying novel concepts of remote entanglement.
suitable as
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Rudolf Gross
Sensing magnetic resonance via nitrogen vacancy centers
Electron spin resonance provides means to very sensitive magnetic field sensors. At present charged nitrogen vacancies in diamond provide unique properties such as optical readout of the electron spin state and spin coherence above room temperature. This allows using this system for magnetic field sensing applications. You will work on implementing an experimental platform for optical readout and microwave manipulation of electron spins in nitrogen vacancy centers in your thesis. The ultimate goal is the detection of magnetic resonance via nitrogen vacancy centers in the new setup. We are searching a skilled master student to start the experiments on optically detected electron spin resonance. You will optimize the optical setup used for the detection of spin dynamics to improve the noise floor. In addition, you will work with state-of-the-art microwave equipment to drive the magnetization dynamics of the electron spin. After assessing the performance of the setup with state-of-the-art magnetic systems, you will work on detecting magnetic resonance phenomena in solid state systems.
suitable as
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Thin film material design for future magnonics
Spin waves (magnons) are the quantized excitations of the magnetic lattice in solid state systems. The field of magnonics is exploring concepts to use these magnons for information transport and processing. Of special interest is to obtain reliable control over the relevant properties of these magnons such as, for example, their lifetime. The goal of your thesis is to fabricate high quality magnetically ordered thin film structures and investigate their spin wave properties via microwave spectroscopy methods. You will gain experience in nanofabrication by working with state-of-the-art thin film deposition machines. Moreover, you will utilize thin film x-ray diffraction and magnetometry experiments to characterize the materials. You will utilize microwave spectroscopy techniques to extract the spin wave properties.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Rudolf Gross

Current and Finished Theses in the Group

Fabrication of low-loss Josephson parametric devices
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Rudolf Gross
Magnetoelastic coupling in CoFe-heterostructures
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Gross
Magnon transport in antiferromagnetic insulator
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Gross
Microwave cryptography with propagating quantum tokens
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Gross
Observation of quantum switching in driven-dissipative superconducting oscillators / Observation of quantum switching in driven-dissipative superconducting oscillators
Abschlussarbeit im Masterstudiengang Quantum Science & Technology
Themensteller(in): Rudolf Gross
Unconventional Superconducting Materials
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Gross
Investigation of the microscopic process and limitations of qubit frequency targeting by laser annealing
Abschlussarbeit im Masterstudiengang Quantum Science & Technology
Themensteller(in): Stefan Filipp
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