In quantum technologies, presently no hardware platform fulfills all requirements for useful applications. Thus, hybrid systems that fortuitously combine the advantageous properties of different quantum systems, while circumventing their disadvantageous characteristics, are extremely powerful. The NeQuS project aims to establish such hybrid quantum systems, in which nodes located in different research institutes are linked together using quantum interfaces. The nodes will be based on different hardware platforms including all major systems investigated in quantum technology: superconducting circuits, trapped atoms, nanomechanical resonators, and spins in solids. The project aims at interfacing all of these platforms via quantum states of light propagating in room-temperature optical fibers.

The key challenge in this context is that the individual platforms operate at very different energy scales. While superconducting quantum circuits and nanoelectromechanical systems use microwave photons with characteristic energies in the range of 10^-6 -10^-5 eV, neutral atoms and spins in solids emit visible or infrared photons with an energy around 1 eV - each at a different frequency. To be able to connect these different systems, each of them will establish an interface to photons at telecommunication wavelength. Such photons in the minimal loss regime of optical fibers are ideal carriers of quantum information over many kilometers at ambient temperature, which will lay the ground to distribute entanglement between the different platforms in NeQuS.

Building on established photonic technologies and protocols for quantum state distribution, the central goals of NeQuS are:

• To implement hybrid quantum transducers that allow each platform to generate or receive photons at a telecommunication wavelength
• To develop performant quantum interconnects between the different platforms
• To establish entanglement between the individual systems
• To build quantum network demonstrators and develop protocols for their up-scaling

With these key capabilities, the envisioned hybrid systems will gain access to the full functionality and strengths of each of the involved hardware platforms.

Consortium:

• Walther-Meißer-Institute (BAdW/TUM): K. Fedorov, S. Filipp, R. Gross, H. Hübl
• Technical University of Munich (TUM): J. Finley, K. Müller, A. Reiserer, E. Weig
• Ludwig-Maximilians Universität (LMU): H. Weinfurter
• Max Planck Institute of Quantum Optics (MPQ): G. Rempe

The precise measurement of physical quantities transcends all of the natural and engineering sciences, as well as life sciences and medicine. In the quest to achieve higher precision, and open the doors towards the development of radically new technologies, sensors are now reaching the quantum limit for which the “sensing element” is a discrete quantum system that interacts with its environment.

The central goal of the Lighthouse Project IQSense is to synergistically link leading groups from natural science (physics, chemistry), engineering (electrical engineering, information sciences) with researchers working in life sciences and medicine. Thereby, IQ-Sense will develop and demonstrate integrated quantum sensors for a range of application scenarios, including fast screening methods for biological matter. The project IQSense joins leading Bavarian groups working in materials science and quantum sensing technologies and brings them together with clinicians working on the development of cutting edge imaging and sensing technologies.

Consortium:

• Julius-Maximilians-Universität Würzburg (JMUW): V. Dyakonov, B. Hecht, K. Heinze, S. Höfling, M. Sauer
• Walther-Meißer-Institute (BAdW/TUM): R. Gross, H. Hübl
• Technical University of Munich (TUM): Ch. Back, M. Brandt, D. Bucher, J. Finley, F. Schilling, G. Westmeyer