Extensive double-excitation states in atomic helium

Domke, M.; Xue, C.; Puschmann, A.; Mandel, T.; Hudson, Eric A.; Shirley, D. A.; Kaindl, G.; Greene, Chris H.; Sadeghpour, H. R.; Petersen, H.

doi:10.1103/physrevlett.66.1306

Cited by 208 publications

(106 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 together with experimental data by Kaindl and co-workers [4,29]. Since no absolute photoionization yields are measured in these experiments we have scaled the experimental data to our results.…”

Section: B Typical Cross Sectionsmentioning

confidence: 99%

Intermanifold similarities in partial photoionization cross sections of helium

2002

View full text Add to dashboard Cite

Using the eigenchannel R-matrix method we calculate partial photoionization cross sections from the ground state of the helium atom for incident photon energies up to the N = 9 manifold. The wide energy range covered by our calculations permits a thorough investigation of general patterns in the cross sections which were first discussed by Menzel and co-workers [Phys. Rev. A 54, 2080]. The existence of these patterns can easily be understood in terms of propensity rules for autoionization. As the photon energy is increased the regular patterns are locally interrupted by perturber states until they fade out indicating the progressive break-down of the propensity rules and the underlying approximate quantum numbers. We demonstrate that the destructive influence of isolated perturbers can be compensated with an energy-dependent quantum defect.

show abstract

Section: B Typical Cross Sectionsmentioning

confidence: 99%

Intermanifold similarities in partial photoionization cross sections of helium

2002

View full text Add to dashboard Cite

show abstract

“…One of these channels consists of the direct excitation of an electron to the continuum, while the second involves an intermediate, discrete state that is coupled to the continuum through a so-called configuration interaction [1]. The characteristic signature of the interference of these channels is the Fano resonance (FR) that is observed in scattering experiments, with a line shape that intimately reflects the relative transmission amplitudes of the two ionization pathways [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

et al. 2012

View full text Add to dashboard Cite

We demonstrate a fully tunable realization of a multistate Fano resonance, in which a pair of remote quantum states experience an effective coupling due to their mutual overlap with a continuum. Our mesoscopic implementation of this system exploits the ability of the semiconductor nanostructures known as quantum point contacts (QPCs) to serve, in the low-density limit close to pinch-off, as an on-demand localized state. By coupling the states formed on two separate QPCs, through a two-dimensional electron gas that serves as a continuum, we observe a robust effective interaction between the QPCs. To explain this result, we develop a theoretical formulation, based on the ideas of the Schrieffer-Wolff transformation, which is able to reproduce our key experimental findings. According to this model, the robust character of the interaction between the two remote states arises from the fact that the interaction is essentially mediated by a large number of degenerate continuum states. While the continuum is often viewed as a source of decoherence, our experiment therefore instead suggests the possibility of using this medium to support the interaction of quantum states, a result that may allow new approaches to coherently couple nanostructures in extended geometries.

show abstract

“…The first prominent success of the adiabatic approximation was the grouping together of He autoionizing levels having similar character into one such potential curve [38]. Subsequent studies showed that He and H − photoabsorption is dominated by a small subset of such potential curves [40][41][42], suggesting that Macek's adiabatic scheme is much more than just a mathematical technique for solving the Schrödinger equation, but that it also provides an insightful physical and intuitive formulation that can be used qualitatively and semiquantitatively in the same manner as the BornOppenheimer treatment which has been so successful in molecular physics.…”

Section: Introductionmentioning

confidence: 99%

The hyperspherical four-fermion problem

Rittenhouse

Stecher

D'Incao

et al. 2011

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

View full text Add to dashboard Cite

The problem of a few interacting fermions in quantum physics has sparked intense interest, particularly in recent years owing to connections with the behaviour of superconductors, fermionic superfluids and finite nuclei. This review addresses recent developments in the theoretical description of four fermions having finite-range interactions, stressing insights that have emerged from a hyperspherical coordinate perspective. The subject is complicated, so we have included many detailed formulae that will hopefully make these methods accessible to others interested in using them. The universality regime, where the dominant length scale in the problem is the two-body scattering length, is particularly stressed, including its implications for the famous BCS-BEC crossover problem. Derivations and relevant formulae are also included for the calculation of challenging few-body processes such as recombination.

show abstract

Extensive double-excitation states in atomic helium

Cited by 208 publications

References 18 publications

Intermanifold similarities in partial photoionization cross sections of helium

Intermanifold similarities in partial photoionization cross sections of helium

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

The hyperspherical four-fermion problem

Contact Info

Product

Resources

About