A. Ekers

Ionization of Rydberg atoms by blackbody radiation

We have studied ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. The calculations have been performed for nS, nP and nD states for principal quantum numbers n=8–65 at ambient temperatures of 77, 300 and 600 K. The calculations take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of the measured ionization rates and their n dependence. A Cooper minimum for BBR-induced transitions between bound Rydberg states of Li has been found. The calculated ionization rates are compared with our earlier measurements of BBR-induced ionization rates of Na nS and nD Rydberg states with n=8–20 at 300 K. Good agreement for all states except nS with n>15 is observed. Useful analytical formulae for quick estimates of BBR ionization rates of Rydberg atoms are presented. Application of BBR-induced ionization signal to measurements of collisional ionization rates is demonstrated.

Focus on modern frontiers of matter wave optics and interferometry

The level of experimental control and the detailed theoretical understanding of matter wave physics have led to a renaissance of experiments testing the very foundations of quantum mechanics and general relativity, as well as to applications in metrology. A variety of interferometric quantum sensors surpasses, or will surpass, the limits of their classical counterparts, for instance in the measurement of frequency and time or forces such as accelerations due to rotation and gravity with applications in basic science, navigation and the search for natural resources. The collection of original articles published in this focus issue of New Journal of Physics is intended as a snapshot of the current research pursued by a number of leading teams working on the development of new matter wave physics, devices and techniques. A number of contributions also stress the close relation between the historic roots of quantum mechanics and aspects of modern quantum information science which are relevant for matter wave physics.

Collisional and thermal ionization of sodium Rydberg atoms III. Experiment and theory for nS and nD states with n = 8-20 in crossed atomic beams

The results of experimental and theoretical studies of collisional ionization of Na Rydberg atoms in nS and nD(n = 8–20) states are presented. Molecular and atomic ions from associative ionization and photoionization by blackbody radiation were detected after pulsed laser excitation of Rydberg states in crossed Na atomic beams. An original method of determination of associative ionization rate constants based on the measurement of ratios of molecular and atomic ion signals was used, which did not require the determination of absolute number density of Rydberg atoms. The measured rate constants of associative ionization of Rydberg atoms in collisions with ground-state Na atoms are compared with the results of our earlier single-beam experiment and theoretical calculations. It is shown that the stochastic ionization model, which describes the collisional ionization of Rydberg atoms in terms of chaotic migration of highly excited electron induced by the motion of the colliding nuclei, yields a significantly better agreement with the experimental results than the earlier Duman–Shmatov–Mihajlov–Janev model.

Ionization of sodium and rubidiumnS,nP, andnDRydberg atoms by blackbody radiation

Results of theoretical calculations of ionization rates of Rb and Na Rydberg atoms by blackbody radiation BBR are presented. Calculations have been performed for nS, nP, and nD states of Na and Rb, which are commonly used in a variety of experiments, at principal quantum numbers n =8–6 5 and at three ambient temperatures of 77, 300, and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of measured ionization rates and shapes of their dependences on n. The calculated ionization rates are compared with the results of our earlier measurements of BBR-induced ionization rates of Na nS and nD Rydberg states with n =8–2 0 at 300 K. Agood agreement for all states except nS with n 15 is observed. We also present the useful analytical formulas for the quick estimation of BBR ionization rates of Rydberg atoms.

Ionization of nS, nP, and nD lithium, potassium, and cesium Rydberg atoms by blackbody radiation

The results of theoretical calculations of the blackbody ionization rates of lithium, potassium, and cesium atoms residing in Rydberg states are presented. The calculations are performed for nS, nP, and nD states in a wide range of principal quantum numbers, n = 8−65, for blackbody radiation temperatures T = 77, 300, and 600 K. The calculations are performed using the known quasi-classical formulas for the photoionization cross sections and for the radial matrix elements of transitions in the discrete spectrum. The effect of the blackbody-radiation-induced population redistribution between Rydberg states on the blackbody ionization rates measured under laboratory conditions is quantitatively analyzed. Simple analytical formulas that approximate the numerical results and that can be used to estimate the blackbody ionization rates of Rydberg atoms are presented. For the S series of lithium, the rate of population of high-lying Rydberg levels by blackbody radiation is found to anomalously behave as a function of n. This anomaly is similar to the occurrence of the Cooper minimum in the discrete spectrum.

Dissociative charge transfer from highly excited Na Rydberg atoms to vibrationally excited Na2 molecules

Abstract We report the observation of the vibrational dependence of dissociative charge transfer (DCT), Na 2 ( X 1 Σ g + , v″) + Na∗∗( nl ) → Na − + Na + Na + , in a single Na/Na 2 supersonic beam at low intrabeam collision energies (1.6 meV) using the STIRAP technique for selective vibrational excitation of Na 2 in the electronic ground state and time-of-flight mass analysis of the ions. The efficiency of this process increases by about an order of magnitude in the range 13 ≤ v″ ≤ 22. Some perspectives are discussed regarding the implementation of a field-free ion-imaging technique for the detection of ions that will allow the direct determination of the kinetic energy distributions of product negative ions and thus distinguish among different possible mechanisms of the DCT process. The first results of test experiments on imaging of photodissociation products of Na 2 (v″) without an extraction field are presented, confirming the potential of the new detection concept.

Publisher's Note: Line shapes and time dynamics of the Förster resonances between two Rydberg atoms in a time-varying electric field [Phys. Rev. A 94 , 043417 (2016)]

E. A. Yakshina, D. B. Tretyakov, I. I. Beterov, V. M. Entin, C. Andreeva, A. Cinins, A. Markovski, Z. Iftikhar, A. Ekers, and I. I. Ryabtsev Rzhanov Institute of Semiconductor Physics SB RAS, 630090 Novosibirsk, Russia Novosibirsk State University, 630090 Novosibirsk, Russia Institute of Electronics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria University of Latvia, LV-1002 Riga, Latvia Technical University of Sofia, 1000 Sofia, Bulgaria Institut d’Optique, 91127 Palaiseau, France and King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia (Dated: 24 October 2016)

Ionization of Rb and Na Rydberg atoms by blackbody radiation

This work presents the results of the numerical calculations of (blackbody radiation) BBR-induced photoionization rates of Rb and Na Rydberg nS, nP and nD atoms with n = 8-65 at the ambient temperatures of 77, 300 and 600 K.