High-Q magnetic levitation and control of superconducting microspheres at millikelvin temperatures

Joachim Hofer, Gerard Higgins, Hans Huebl, Oliver F. Kieler, Reinhold Kleiner, Dieter Koelle, Philip Schmidt, Joshua A. Slater, Michael Trupke, Kevin Uhl, Thomas Weimann, Witlef Wieczorek, Friedrich Wulschner, Markus Aspelmeyer

We report the levitation of a superconducting lead-tin sphere with 100 micrometer diameter (corresponding to a mass of 5.6 micrograms) in a static magnetic trap formed by two coils in an anti-Helmholtz configuration, with adjustable resonance frequencies up to 240 hertz. The center-of-mass motion of the sphere is monitored magnetically using a dc-SQUID as well as optically and exhibits quality factors of up to 2.6e7. We also demonstrate 3D magnetic feedback control of the sphere's motion. By implementing a cryogenic vibration isolation system we can attenuate environmental vibrations at 200 hertz by approximately seven orders of magnitude. The combination of low temperature (15 millikelvin), large mass and high quality factor as well as adjustable resonance frequencies provides a promising platform for testing quantum physics in previously unexplored regimes with high mass and long coherence times.

Quantum Optics, Quantum Nanophysics and Quantum Information
External organisation(s)
Österreichische Akademie der Wissenschaften (ÖAW), Chalmers University of Technology, Bayerische Akademie der Wissenschaften, Technische Universität München, Munich Center for Quantum Science and Technology (MCQST), Physikalisch-Technische Bundesanstalt, Eberhard Karls Universität Tübingen, Vienna Center for Quantum Science and Technology (VCQ)
No. of pages
Publication date
Austrian Fields of Science 2012
103025 Quantum mechanics
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