Quantum Systems

Prof. Dr. Ronny STOLZ

Email: ronny.stolz@leibniz-ipht.de, ronny.stolz@uni-jena.de

Phone: +49 3641-206-119

Dr. Ronny Stolz is the head of the Quantum Systems department at the Leibniz Institute of Photonic Technology (Leibniz IPHT). He is board member of the FLUXONICS foundry and the Applied Superconductivity Educational Foundation. He was granted with a number and prizes of awards such as in 2017 the ESAS Award for Excellence. Currently, he coordinates various R&D projects in the research field of Quantum Technology and according key enabling technology.

The department Quantum Systems addresses the topics quantum computing and simulation, quantum sensing and metrology as well as quantum communication on the atomic and solid-state superconducting quantum technology platforms. The research is focused on exploiting quantum effects for applications by investigating quantum dynamics between single objects, in large systems as well as in their interaction with electromagnetic radiation. In this context quantum engineering, which means ensuring quantum operation in complex devices, is one important topic and is used to enable operation at utmost performance as well as new functionalities in applications of socially relevant fields such as health technology and medicine, life and environmental sciences, geoscience, as well as security. Together with the Competence Center for Micro- and Nanotechnology at Leibniz-IPHT, the group holds the whole research and development chain from circuit design and simulation, thin-film fabrication technology over integration technology up to complete instruments and according software tools are covered.

Research Areas

Research targets of Ronny Stolz and his group lay in the application-oriented implementation of quantum systems. The research topics include:

Quantum dynamics in superconducting and atomic systems,
Superconducting qubits and quantum computation,
Quantum engineering, enabling technology, and integration technology,
Fabrication technology for superconducting and atomic quantum systems and devices,
Superconducting sensors and applications,
Radiation detectors at different wavelengths from XUV to microwave aiming for single photon resolution,
Photonic magnetometers and their applications.

Teaching Fields

Dr. Ronny Stolz teaches students in the courses M.Sc. Physics and M.Sc. Photonics, B.Sc. and M.Sc. Geophysics. He offers lectures in:

Superconductivity,
Experimental Quantum Technology
Geophysical mineral exploration methods
Magnetic, electromagnetic and gravimetric methods in Geophysics,
Matlab™ für Geoscientists

Research Methods

The laboratories of the department at Leibniz IPHT hosts world-unique facilities for example:

Shared clean room area with capabilities for thin film technology in the context of superconducting quantum circuits and a number of integration technology such as wafer and wire bonding,
Characterization labs with tools for ultralow noise measurement over a wide frequency range from DC to 26 GHz, microwave and optical testing equipment,
Cryogenic setups for measurement at different temperatures down to 10 mK with electrical and optical access,
Optical setups for atomic spectroscopy of alkali vapors,
Specialized ultralow-noise setups such as electromagnetically or magnetically shielded rooms,
Calibration facilities for magnetic field and gradients.

Recent Research Results

Researchers at Leibniz IPHT prepare the mK measurement platform for first use in the framework of the collaborative project QSolid.
Image: Leibniz IPHT

The department of Quantum systems headed by Ronny Stolz has currently two main topics:

Quantum-limited magnetic field sensors enable the detection of the magnetic field and its gradients at utmost resolution which is fundamentally limited by standard quantum limits connected to the measurement principle. Customized optically pumped magnetometers [1, 2] and superconducting magnetometers enable a wide range of applications in life and environmental sciences, such as biomagnetism [3] and geomagnetism [4, 5]. New sensing concepts with advanced functionality, such as omni-directional and vector-type measuring instruments, are developed from experimental and theoretical investigations. Current work also includes multi-channel and imaging instruments (magnetic field camera and gradiometer, respectively) to open up new R&D fields.

Superconducting solid-state quantum systems represent one of the most promising platforms for implementations of quantum technology to date. They serve as research objects for fundamental quantum dynamics such as light-matter interaction and can be used for a variety of applications due to their circuit character and a high degree of integration. Applications as quantum computing, simulation, sensing and communication as well as key enabling technology are addressed. Examples include the use of new materials such as ultrathin niobium nitride (NbN) [6], ultrasensitive detection of microwave photons [7], initial experiments on single large-area Josephson junctions (STJs) as XUV radiation detectors, and promising developments in the field of microwave multiplexers and superconducting digital circuits [8] for multi-channel sensor and qubit readout or control. Especially the integration of optical circuit elements with superconducting solid-state-based quantum systems in a hybrid technology platform will enable next generation quantum systems.

All R&D activities of the department are application driven and base on the 20+ years of expertise in circuit design, fabrication, system integration technology, electronic design and software implementation.

[1] Oelsner et al., Phys. Rev. Appl. 17, 024034 (2022).
[2] Oelsner et al., EPJ Quantum Technol. 6, 634 (2019).
[3] Jaufenthaler et al., EPJ Quantum Technol. 7, 623 (2020).
[4] Stolz et al., Supercond. Sci. Technol. 34, 033001 (2021).
[5] Rabiger-Völlmer et al., Remote Sens. 22, 4647 (2021).
[6] Knehr et al., Supercond. Sci. Technol. 32, 125007 (2019).
[7] Golubev et al., Phys. Rev. Appl. 16, 014025 (2021).
[8] Kunert et al., Low Temp. Phys. 43, 785 (2017).

Link to the Quantum Systems group at Leibniz IPHTExternal link