Rydberg atoms in time-dependent electric fields

David A. Harmin

Limei Wang, Hao Zhang, Linjie Zhang +5 more

The high-l Rydberg Stark states are populated by the state transfer from initial prepared nS Rydberg state via avoided crossings induced by a weak electric-field pulse, and investigated by the state selective field ionization method in a cesium standard magneto-optical trap. The dependences of the transfer rate, given by the ratio of the number of high-l Stark states to all atoms, on the strength and holding time of electric-field pulse are investigated and compared with those with additional ions. The results show that the time evolution of high-l Stark states strongly depends on the electric-field strength, and is affected by the additional ions at relatively weaker field (1.51 V/cm here). The density of Rydberg atoms has a minor effect on the characteristic time of evolution process.

Eliane Luc-Koenig, J. M. Lecomte

E. Vliegen, Frédéric Merkt

Argon atoms in a pulsed supersonic expansion are prepared in selected Stark components of Rydberg states with effective principal quantum number in the range n * = 15–25. When traversing regions of inhomogeneous electric fields, these atoms get accelerated or decelerated depending on whether the Stark states are low- or high-field seeking states. Using a compact electrode design, which enables the application of highly inhomogeneous and time-dependent electric fields, the Rydberg atoms experience kinetic energy changes of up to 1.2 × 10 −21 J (i.e. 60 cm −1 in spectroscopic units) in a single acceleration/deceleration stage of 3 mm length. The resulting differences in the velocities of the low- and high-field seeking states are large enough that the corresponding distributions of times of flight to the Rydberg particle detector are fully separated. As a result, efficient spectral searches of the Rydberg states best suited for acceleration/deceleration experiments are possible. Numerical simulations of the particle trajectories are used to analyse the time-of-flight distributions and to optimize the time dependence of the inhomogeneous electric fields. The decay of the Rydberg states by fluorescence, collisions and transitions induced by black-body radiation takes place on a timescale long enough not to interfere significantly with the deceleration during the first ∼5 µs.

S. Feneuille

I. I. Ryabtsev, Denis B. Tretyakov, Vasily M. Entin +3 more

Long-range interactions between cold Rydberg atoms are being investigated for neutral-atom quantum computing, quantum simulations, phase transitions in cold Rydberg gases and other applications. Fine tuning of the interaction strength can be implemented using Förster resonances between Rydberg atoms controlled by an electric field. The observation of the Stark-tuned Förster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the Förster resonance. The application of the radio-frequency field causes additional Förster resonances between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a single interaction volume yields a cusped line shape of the Förster resonance. We present a detailed experimental and theoretical analysis of the line shape and time dynamics of the Stark-tuned Förster resonances Rb( nP 3/2 ) + Rb( nP 3/2 ) → Rb( nS 1/2 ) + Rb([ n + 1] S 1/2 ) for two Rb Rydberg atoms interacting in a time-varying electric field.