2014/02/28 by Tobias Thiele, Thomas Thiele, Stefan Filipp +10 · 1 citation
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #Quantum, superfluid, helium dynamics #cond-mat.mes-hall #physics.atom-ph #quant-ph
paper · pdf · doi:10.1103/physreva.90.013414
published as Phys. Rev. A 90, 013414 (2014) · 12 pages, 10 figures
arxiv created 2014/02/28 · openalex publication_date 2014/07/14 · arxiv updated 2014/07/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Helium atoms in Rydberg states have been manipulated coherently with microwave radiation pulses near a gold surface and near a superconducting NbTiN surface at a temperature of 3\phantom\rule0.28em0exK. The experiments were carried out with a skimmed supersonic beam of metastable (1s)1(2s)1\phantom\rule0.28em0ex1S0 helium atoms excited with laser radiation to np Rydberg levels with principal quantum number n between 30 and 40. The separation between the cold surface and the center of the collimated beam is adjustable down to 250\phantom\rule0.28em0ex\ensuremathμm. Short-lived np Rydberg states were coherently transferred to the long-lived ns state to avoid radiative decay of the Rydberg atoms between the photoexcitation region and the region above the cold surfaces. Further coherent manipulation of the ns Rydberg states with pulsed microwave radiation above the surfaces enabled measurements of stray electric fields and allowed us to study the decoherence of the atomic ensemble. Adsorption of residual gas onto the surfaces and the resulting slow buildup of stray fields was minimized by controlling the temperature of the surface and monitoring the partial pressures of H2O, N2, O2, and CO2 in the experimental chamber during the cool-down procedure. Compensation of the stray electric fields to levels below 100\phantom\rule0.28em0exmV/cm was achieved over a region of 6\phantom\rule0.28em0exmm along the beam-propagation direction which, for the 1770-m/s beam velocity, implies the possibility to preserve the coherence of the atomic sample for several microseconds above the cold surfaces.