Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 31: Ultracold Atoms: Trapping and Cooling I (with Q)

A 31.2: Talk

Thursday, March 26, 2015, 11:30–11:45, P/H2

"Second-order magic" radio-frequency dressing for magnetically trapped 87Rb atoms. — •Georgy Kazakov and Thorsten Schumm — Institute of Atomic and Subatomic Physics, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

We consider the modification of magnetic trap potential what allow to decrease the position-dependent decoherence in trapped atomic ensembles. To mitigate the perturbing effects of the magnetic trap, "near-magic field" configurations are usually employed, where the involved clock transition becomes independent of the atoms potential energy to first order. Still, higher order effects are a dominating source for dephasing, limiting the perfomance of this approach.

Here we propose a simple method to cancel the energy dependence to both, first and second order, using weak radio-frequency dressing. We give corresponding values of dressing frequencies, amplitudes, and trapping fields for 87Rb atoms, and investigate quantitatively the robustness of these "second-order magic" conditions to variations of the trapping field and dressing field amplitude and polarization. We conclude that such radio-frequency dressing can suppress field-induced dephasing by at least one order of magnitude in comparison with "ordinary" magic trap without dressing.