Autoionization of an ultracold Rydberg gas through resonant dipole coupling

Amthor, Thomas; Denskat, J.; Giese, Christian; Безуглов, Н. Н.; Экерс, А.; Cederbaum, Lorenz S.; Weidemüller, Matthias

doi:10.1140/epjd/e2009-00119-4

Cited by 39 publications

(42 citation statements)

References 30 publications

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“…By extending the models for mechanism i ) and ii ) described in Ref. [44] and Ref. [26], respectively, to higherorder interaction terms and larger basis sets, we verified that neither mechanism can explain decay rates exceeding 1 kHz for the macrodimer states investigated here, even for vibrationally excited levels.…”

supporting

confidence: 69%

Observation of Rydberg-Atom Macrodimers: Micrometer-Sized Diatomic Molecules

Saßmannshausen

Deiglmayr

2016

Phys. Rev. Lett.

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Long-range metastable molecules consisting of two cesium atoms in high Rydberg states have been observed in an ultracold gas. A sequential three-photon two-color photoassociation scheme was employed to form these molecules in states, which correlate to np(n + 1)s dissociation asymptotes. Spectral signatures of bound molecular states are clearly resolved at the positions of avoided crossings between long-range van der Waals potential curves. The experimental results are in agreement with simulations based on a detailed model of the long-range multipole-multipole interactions of Rydbergatom pair states. We show that a full model is required to accurately predict the occurrence of bound Rydberg macrodimers. The macrodimers are distinguished from repulsive molecular states by their behavior with respect to spontaneous ionization and possible decay channels are discussed.A new regime of ultracold chemistry has been established by the possibility to routinely produce ultracold atomic samples with translational temperatures below 1 mK using laser cooling [1,2] and trapping [3,4]. The characteristic feature of this regime is that reactions are not driven by thermodynamical quantities, i.e. temperature or pressure, but by the precise manipulation of the internal quantum states of the constituents and the interactions between them. Landmark results in the emerging field of ultracold chemistry include the formation of ultracold molecules in the absolute ground state using photoassociation [5][6][7] or magneto-association [8,9], the control of chemical reactions by manipulating the quantum statistics of the reactants [10,11], or the photodissociation of molecules with full control over reactant and product channels [12]. The enabling factor in all these studies is the control of long-range interaction potentials, which dominate the dynamics at low collision energies.An extreme case of long-range interactions are van der Waals forces between two atoms in Rydberg states, scaling in the case of an off-resonant dipole-dipole interaction with the internuclear separation R as R −6 and with the principal quantum number n as n 11 [13]. Metastable molecular states with internuclear separations exceeding 1 µm, so called macrodimers, are predicted to result from these interactions [14][15][16]. The molecular potential minima supporting these bound states arise from avoided crossings between long-range potential-energy curves correlating to different dissociation asymptotes of the doubly-excited dimers (see Fig. 1). Astonishingly, such macrodimers are predicted to have lifetimes limited by radiative decay of the constituent atomic Rydberg states [17], even though they are energetically located in the Cs + Cs + + e − ionization continuum and the density of electronic states is extremely high, two conditions one would expect to lead to fast autoionization [18]. Experimentally, these molecular states have remained elusive. Molecular resonances were observed in the Rydberg-excitation spectrum of ultracold gases and were identified as arisi...

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supporting

confidence: 69%

Observation of Rydberg-Atom Macrodimers: Micrometer-Sized Diatomic Molecules

Saßmannshausen

Deiglmayr

2016

Phys. Rev. Lett.

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“…In our case, a decrease in the linewidth of laser radiation from 10 GHz to 1 MHz leads to a 10 4 time decrease in the generation probability of photo ions, whereby the latter will hardly affect the observed spectra. This will allow one to analyze other possible sources of formation of ultracold plasma in dense ensembles of cold Rydberg atoms, such as the photo ionization of Rydberg atoms by background thermal radiation [18], the Penning ionization under dipoledipole interaction of Rydberg atoms [19], and the photoionization of cold atoms by laser radiation [20]. …”

Section: Discussionmentioning

confidence: 99%

Effect of photoions on the line shape of the Förster resonance lines and microwave transitions in cold rubidium Rydberg atoms

Tretyakov

Бетеров

Энтин

et al. 2012

J. Exp. Theor. Phys.

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Experiments are carried out on the spectroscopy of the Förster resonance lines Rb(37P) + Rb(37P) Rb(37S) + Rb(38S) and microwave transitions nP n'S, n'D between Rydberg states of cold rubidium atoms in a magneto optical trap (MOT). Under ordinary conditions, all spectra exhibit a linewidth of 2-3 MHz irrespective of the interaction time between atoms or between atoms and microwave radiation, although the limit resonance width should be determined by the inverse interaction time. The analysis of exper imental conditions has shown that the main source of line broadening is the inhomogeneous electric field of cold photoions that are generated under the excitation of initial nP Rydberg states by broadband pulsed laser radia tion. The application of an additional electric field pulse that rapidly extracts photoions produced by a laser pulse leads to a considerable narrowing of lines of microwave resonances and the Förster resonance. Various sources of line broadening in cold Rydberg atoms are analyzed.

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“…However, even at 20 µK the motional effects from the attractive interactions can be significant on timescales of tens of microseconds [19,20]. Figure 1 (b) shows the dipole-dipole interaction potential V (R) for the 58D 5/2 pair state as a function of interatomic separation.…”

Section: Temporal Dependence Of the Eit Lineshapementioning

confidence: 99%

Optical non-linearity in a dynamical Rydberg gas

Pritchard¹,

Gauguet²,

Weatherill³

et al. 2011

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. We use the technique of electro-magnetically induced transparency (EIT) to probe the effect of attractive dipole-dipole interactions in a highly excited Rydberg gas. The transient character of the EIT response is investigated by rapidly scanning the probe laser through resonance. We characterize the resulting cooperative optical non-linearity as a function of probe strength, density and scan direction. For the 58D 5/2 Rydberg state, an atom density of 1.6 × 10 10 cm −3 and a positive frequency scan we measure a third-order non-linearity of χ (3) = 5 × 10 −7 m 2 V −2 . For the reverse scan we observe a second order non-linearity of χ (2) = 5 × 10 −6 mV −1 . The contrasting behaviour can be explained in terms of motional effects and resonant excitation of Rydberg pairs.

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Autoionization of an ultracold Rydberg gas through resonant dipole coupling

Cited by 39 publications

References 30 publications

Observation of Rydberg-Atom Macrodimers: Micrometer-Sized Diatomic Molecules

Observation of Rydberg-Atom Macrodimers: Micrometer-Sized Diatomic Molecules

Effect of photoions on the line shape of the Förster resonance lines and microwave transitions in cold rubidium Rydberg atoms

Optical non-linearity in a dynamical Rydberg gas

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