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Q: Fachverband Quantenoptik und Photonik

Q 7: Ultracold plasmas and Rydberg systems I (with A)

Q 7.2: Vortrag

Montag, 17. März 2014, 10:45–11:00, DO24 1.101

Beyond the Rydberg van-der-Waals Interaction in Thermal Caesium Vapour. — •Alban Urvoy¹, Fabian Ripka¹, David Peter², Tilman Pfau¹, and Robert Löw¹ — ¹5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart Germany — ²Institut für Theoretische Physik III, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart Germany

Rydberg atoms are promising candidates for the realisation of quantum devices, making use of their long-range atom-atom interaction. The presence of van der Waals-type interaction among Rydberg states has recently been demonstrated in thermal rubidium vapour using a pulsed amplifier [1]. We expanded this work to higher atom number density (typ. 10¹² to 10¹⁴ cm⁻³) in caesium vapour and observed two types of atomic response by varying the laser detuning. The border between these two regimes is phase-transition-like. One type of excitation dynamics is consistent with a two-body excitation process, while the other is of many-body nature. We deduce this interpretation from the scaling behaviour of the transition point with Rabi frequency, atom number density and principal quantum number. At such high densities and large excitation bandwidths (≈ 500 MHz), we find that the crossings of the potential of the pair-state of interest with those of neighbouring pair-states become relevant. These modify the pair-state potentials, and allows for direct pair-state excitation at detunings beyond the excitation bandwidth.
T. Baluktsian, B. Huber, et al., PRL 110, 123001 (2013)