Ultracold atoms in miniaturized traps enable intriguing possibilities for the manipulation of atomic matter waves and for the controlled interaction between atoms with solid surfaces. In tight collaboration with the group of J. Fortágh we develop and use cryo-cooled microtraps for the coherent manipulation of ultracold atoms and Bose-Einstein condensates (BECs) and for the investigation of coupling mechanisms between atoms and superconductors.

Apart from the investigation of basic properties, we focus on the coupling between ultracold atoms and superconducting devices (resonators, superconducting rings, Josephson junctions, SQUIDs). This shall lead to the construction of coupled hybrid quantum systems, consisting of BECs and superconducting devices in the quantum regime, which e.g. may enable the realization of new types of ultra-sensitive devices.

For more information, please see the project homepage of the group of J. Fortágh.
 

C. Zimmermann, J. Fortágh, D. Kölle. Bose-Einstein-Kondensate am Chip. In Themenheft Forschung "Quantenmaterie" No.5, S.58, Univ. Stuttgart (2008)

H. Hattermann, D. Bothner, L. Y. Ley, B. Ferdinand, D. Wiedmaier, L. Sárkány, R. Kleiner, D. Koelle, J. Fortágh. Coupling ultracold atoms to a superconducting coplanar waveguide resonator. Nature Commun. 8, 2254 (2017)

D. Bothner, D. Wiedmaier, B. Ferdinand, R. Kleiner, D. Koelle. Improved superconducting resonators in magnetic fields by reduced field focussing and engineered flux screening. Phys. Rev. Applied 8, 034025 (2017)

P. Weiss, M. Knufinke, S. Bernon, D. Bothner, L. Sárkány, C. Zimmermann, R. Kleiner, D. Koelle, J. Fortágh, H. Hattermann. Sensitivity of ultracold atoms to quantized flux in a superconducting ring. Phys. Rev. Lett. 114, 113003 (2015)

F. Jessen, M. Knufinke, S. C. Bell, P. Vergien, H. Hattermann, P. Weiss, M. Rudolph, M. Reinschmidt, K. Meyer, T. Gaber, D. Cano, A. Guenther, S. Bernon, D. Koelle, R. Kleiner, J. Fortágh. Trapping of ultra cold atoms in a ³He/⁴He dilution refrigerator. Appl. Phys. B 116, 665-671 (2014)

D. Bothner, M. Knufinke, H. Hattermann, R. Wölbing, B. Ferdinand, P. Weiss, S. Bernon, J. Fortágh, D. Koelle, R. Kleiner. Inductively coupled superconducting half wavelength resonators as persistent current traps for ultracold atoms. New J. Phys. 15, 093024 (2013)

S. Bernon, H. Hattermann, D. Bothner, M. Knufinke, P. Weiss, F. Jessen, D. Cano, M. Kemmler, R. Kleiner, D. Koelle, J. Fortágh. Manipulation and coherence of ultra-cold atoms on a superconducting atom-chip. Nature Commun. 4, 2380 (2013)

D. Bothner, T. Gaber, M. Kemmler, D. Koelle, R. Kleiner, S. Wünsch, M. Siegel. Magnetic hysteresis effects in superconducting coplanar microwave resonators. Phys. Rev. B 86, 014517 (2012)

D. Bothner, C. Clauss, E. Koroknay, M. Kemmler, T. Gaber, M. Jetter, M. Scheffler, P. Michler, M. Dressel, D. Koelle, R. Kleiner. Reducing vortex losses in superconducting microwave resonators with microsphere patterned antidot arrays. Appl. Phys. Lett. 100, 012601 (2012)

D. Cano, H. Hattermann, B. Kasch, C. Zimmermann, R. Kleiner, D. Koelle, J. Fortágh. Experimental system for research on ultracold atomic gases near superconducting microstructures. Eur. Phys. J. D 63, 17 (2011)

D. Bothner, T. Gaber, M. Kemmler, D. Koelle, R. Kleiner. Improving the performance of superconducting microwave resonators in magnetic fields. Appl. Phys. Lett. 98, 102504 (2011)

B. Kasch, H. Hattermann, D. Cano, T. E. Judd, S. Scheel, C. Zimmermann, R. Kleiner, D. Koelle, J. Fortágh. Cold atoms near superconductors: Atomic spin coherence beyond the Johnson noise limit. New J. Phys. 12, 065024 (2010)

D. Cano, B. Kasch, H. Hattermann, R. Kleiner, C. Zimmermann, D. Koelle, J. Fortágh. Meissner Effect in Superconducting Microtraps. Phys. Rev. Lett. 101, 183006 (2008)

D. Cano, B. Kasch, H. Hattermann, D. Koelle, R. Kleiner, C. Zimmermann, J. Fortágh. Impact of the Meissner Effect on Magnetic Microtraps for Neutral Atoms Near Superconducting Thin Films. Phys. Rev. A 77, 063408 (2008)

A. Guenther, S. Kraft, M. Kemmler, D. Koelle, R. Kleiner, C. Zimmermann, J. Fortagh. Diffraction of a Bose-Einstein Condensate from a Magnetic Lattice on a Micro Chip. Phys. Rev. Lett. 95, 170405 (2005)

A. Guenther, M. Kemmler, S. Kraft, C. J. Vale, C. Zimmermann, J. Fortagh. Combined Chips for Atom-Optics. Phys. Rev. A 71, 063619 (2005)