Physikalisches Institut

Quantenoptik & Ultrakalte Atome



Quantum science deals with various aspects of physics taking place on the level of single atoms up to large systems with emerging quantum phenomena.It also looks at the development of quantum measurement and quantum information technologies. Several research fields contribute to the breathtakingdevelopment in this area, in fields such as cold atomic physics, photonics, condensed matter physics, material- and nano sciences.Built on the exchange between researchers in these subfields, the group of József Fortágh follows interdisciplinary approaches to deepening insights in quantum science and for the development of innovative quantum technologies.

Atoms, photons, quantum gases, superconducting circuits and nanomechanical systems make up the quantum toolbox of the group. Combining them offers unprecedented opportunities to develop chip-based atomic clocks, quantum sensors, secure communication networks and to process information faster and more efficiently than any conceivable conventional machine. The grand challenge is hereto establish coherent quantum interfaces between printed electronic circuits, nanomachines, atoms andphotons. The development of protocols for quantummeasurements, quantum simulations and information processing complement this research.
Advances in quantum science drive technologies. The group is involved in application inspired international research collaborations and cooperates with industrial partners in the area of optical technologiesRydberg setups, cold atom/solid state interface, 4K and 25mK cryostats,Bose-Einstein condensates at superconductors

Superconducting Microtraps

In view of Hybrid Quantum Systems and future quantum networks, the transmission of quantum information between different systems and nodes becomes increasingly important. In our superconducting atom chip experiment, we use an on-chip microwave resonator to mediate infinite-range interactions between individual Rydberg (super-atoms). With the resonator acting as quantum bus, we aim to realize different quantum gates and microwave-to-optical conversion schemes for future quantum technology.

High resolution Rydberg microscopy

Understanding the temporal and spatial dynamics of long-range interacting quantum systems is of specific importance for future quantum technology and quantum metrology. Thereby, ultracold ensembles of Rydberg atoms offer themselves as perfect model system, as they allow for precise and rapid tuning of the corresponding interaction strength. Using a high-resolution ion microscope, we investigate the static and dynamic behavior of such systems and measure their spatial-temporal correlations for various dynamic driving schemes. 

Hybrid Quantum-Systems

As of today, the race for quantum computing is in full swing. Various quantum systems compete for the best performance, but a winner is not yet to be seen. Each system suffers from individual weaknesses, such that hybrid approaches which combine the advantageous of individual systems may be the best way to go. In our lab we combine ultracold quantum gases with superconducting circuits in a mK environment in order to achieve long storage times and fast quantum processing for future applications in quantum technology.

Terahertz Rydberg Sensing

The Terahertz frequency band of ~0.1 – 10 THz has for a long timecalled the ‘Terahertz gap’ for lacked sources and detectors. In contrast to this successful effort of developing new sources, most of the standard THz detectors are based on bolometers. Developing improved detectors with better frequency resolution, higher sensitivity and greater portability is therefore a key goal for THz technology. In our lab we are working towards a quantum detector based on Rydberg atoms in a vapor cell for terahertz radiation emitted by solid-state sources such as quantum cascade lasers and Josephson junction emitters

Cold Atoms meet Artificial Intelligence

Machine Learning has become a powerful tool in today’s technology with applications already reaching the consumer market. In our lab we want to employ modern methods of machine learning to quantum technological applications and realize a robust and autonomously controlled platform for ultracold quantum gases. Such a system may not only pave the way to wide spread use of quantum technology but also foster artificial scientific discoveries in quantum science.  

Optical Pumped Magnetometry

Precise measurements of magnetic fields are at the heart of state-of-the art technology with uncountable applications ranging from medicine up to mobile navigation. Thereby, sensors based on optically pumped magnetometry have gained tremendous importance throughout the last years, as they already reach sensitivities comparable to state-of-the-art SQUID detectors. Using an optically pumped magnetometer we investigate measurement schemes for quantum enhanced sensing with possible applications in future quantum technology.

Continous Strontium Lattice Clock

One of the major limitations of the accuracy of optical lattice clocks is due to their cyclic operating scheme. In our experiment we are developing novel methods to enable interruption-free clock operation in order to eliminate this fundamental issue.