Carl-Zeiss-Stiftung Center for Quantum Photonics

Prof. Dr. Fabian Steinlechner at the Lab.

Image: Ira Winkler (Universität Jena)

Since 2023, the Experimental Quantum Information professorship of Fabian Steinlechner is supported within the Carl-Zeiss-Stiftung Center for Quantum Photonics (CZS Center QPhoton)with 1.7 Mio EUR. The Steinlechner group conducts applied research in the field of quantum communication and photonic quantum information processing. Working in close collaboration with partners in academia and industry they aim to bridge the gap between fundamental quantum research and real-world applications. Fabian Steinlechner's research focuses on novel quantum light sources for applications in quantum communication and sensing, efficient processing and detection schemes for high-dimensional quantum information, as well as scalable methods for the transmission of quantum states over long distances. A central goal is to incorporate photonic quantum technologies in robust, field-deployable hardware systems that are suitable for integration in future quantum networks, long-distance atmospheric free-space links, and ultimately satellite-based quantum key distribution sytems.

Schematic representation of optically controlling the rotational and translational motion of photonic micro-rotors, whose size is comparable to the laser wavelength, and which exhibit Mie-like optical resonances.

Image: Pertsch research group and collaborators.

Thomas Pertsch (Jena), Benjamin Stickler (Stuttgart), Sungkun Hong (Ulm)

Tweezer-levitated particles in vacuum offer a unique platform for probing and exploiting quantum aspects of massive mechanical objects. A fascinating prospect is the possibility of using the levitated particle for studying quantum physics on large scales and for developing acceleration and rotation sensors with quantum-limited precision. The field of levitated quantum optomechanics has shown significant progress over the past few years. However, current research has been largely limited to particles with sizes far less than the optical wavelength. To improve existing sensing capabilities and to push quantum experiments to the macroscale, it is desirable to scale up the size and tailor the shape of the particle, which allows for utilizing rich light-matter interactions only available for photonic objects, whose size is comparable to the optical wavelength, and which may thus exhibit Mie-like optical resonances.

In this project, we aim to expand the scope of levitated quantum optomechanics to photonic aspherical particles, whose shape and size is beyond the Rayleigh regime and whose optical response is thus not that of a point dipole. Specifically, we will focus on developing and gaining full quantum motion control over a photonic microrotor, a micron-scale high-aspect-ratio particle with tailored optical and mechanical properties. The successful completion of the proposed project will allow us to achieve quantum-limited control of photonic microrotors, including the cooling of translational and rotational degrees of freedom to the quantum regime. This will pave the way for testing quantum physics in unexplored parameter regimes and for developing levitated gyroscopes as quantum-limited acceleration and rotation sensors with unprecedented controllability.

Symbolic picture of an NV-qubit for sensing of rotational and translational mobilities of active proteins

Picture: Börsch research group

Michael Börsch (Jena), Jörg Wrachtrup (Stuttgart), Fedor Jelezko (Ulm) und Anke Krüger (Stuttgart)

Active proteins control cellular life. The enzyme FoF1-ATP synthase supplies the energy in the form of the ATP molecule, in bacteria, in plants and animals, and in humans. As a rotary nanomotor, this enzyme converts an electrochemical membrane potential into a high-energy chemical bond in ATP in a highly efficient and rapid manner. This stored energy is then used for cellular processes. The complex random dynamics of the three-step motor function can only be observed under the microscope in a spatiotemporally separated, single enzyme. Quantum sensors such as the NV color center in nanodiamonds can detect three-dimensional motion with the highest precision when suitably attached to active proteins as markers. 

In this CZS Center QPhoton Innovation project, the expertise in the production of NV-doped nanodiamonds and the measurement and analysis methods of NV spin manipulation are combined with a sensitive but rigid coupling chemistry of solids to soft proteins in aqueous solution. The rotary motor of the purified, modified FoF1-ATP synthase thus drives the tethered sensor, and the NV quantum sensor reports on all individual steps of the motor. Twenty years after the first joint preliminary considerations for this project, all experimental requirements are now being met, and the FoF1-ATP synthase (Jena), the coupling chemistry (Stuttgart), the quantum sensor module (Stuttgart) and the NV spin manipulation tools are being used at the three locations (Ulm) prepared for collaborative quantum-based research of single active proteins at work.