Atom Symmetry Break and Metastable Level Coupling in Rare Gas Atom-Surface van der Waals Interaction

Boustimi, M.; Lesegno, B. Viaris de; Baudon, J.; Robert, J.; Ducloy, M.

doi:10.1103/physrevlett.86.2766

Cited by 30 publications

(29 citation statements)

References 11 publications

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“…(5) and (8), i.e., in the regime Z ≪ 1/E q , which is equivalent to the limit χ → 0. For close approach of the atom to the wall, the interaction energy is well described by the static potential (11), which necessitates a diagonalization of the Schrödinger Hamiltonian plus the nonretarded potential V (both "diagonal" interaction and Lamb shift or fine structure terms, as well as "mixing" terms) in the basis of the |2S 1/2 , |2P 1/2 , and |2P 3/2 Schrödinger-Pauli wave functions with magnetic projection µ = +1/2, to form the manifestly coupled states |S 1/2 , |P 1/2 , and |P 3/2 . We denote the (free-space) fine-structure and the Lamb shift interval as…”

Section: −4mentioning

confidence: 99%

“…(11)] gradually become important. [These are obtained by straightforward expansion of the potential (11).] Numerically determined admixtures of the coupled |S 1/2 are given in Fig.…”

Section: −4mentioning

confidence: 99%

“…The symmetry breaking induced by the wall leads to dipole-quadrupole mixing terms, which lead to admixtures to metastable levels [11,12]. While this effect has been analyzed in the non-retarded van-der-Waals regime [11,12], a fully quantum electrodynamic calculation of this effect would be of obvious interest. This fact is emphasized by the curious observation of a long-range, and conceivably super-long-range (micrometer-scale) interaction of metastable hydrogen 2S atoms with a conducting surface (the so-called Sokolov effect, see Refs.…”

mentioning

confidence: 99%

“…[10]. The symmetry breaking induced by the wall leads to dipole-quadrupole mixing terms, which lead to admixtures to metastable levels [11,12]. While this effect has been analyzed in the non-retarded van-der-Waals regime [11,12], a fully quantum electrodynamic calculation of this effect would be of obvious interest.…”

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confidence: 99%

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Long-range atom-wall interactions and mixing terms: Metastable hydrogen

Jentschura

2015

Phys. Rev. A

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We investigate the interaction of metastable 2S hydrogen atoms with a perfectly conducting wall, including parity-breaking S-P mixing terms (with full account of retardation). The neighboring 2P 1/2 and 2P 3/2 levels are found to have a profound effect on the transition from the short-range, nonrelativistic regime, to the retarded form of the Casimir-Polder interaction. The corresponding P state admixtures to the metastable 2S state are calculated. We find the long-range asymptotics of the retarded Casimir-Polder potentials and mixing amplitudes, for general excited states, including a fully quantum electrodynamic treatment of the dipole-quadrupole mixing term. The decay width of the metastable 2S state is roughly doubled even at a comparatively large distance of 918 atom units (Bohr radii) from the perfect conductor. The magnitude of the calculated effects is compared to the unexplained Sokolov effect. , research on related matters has found continuously growing interest over the last decades [5][6][7][8]. In the non-retarded regime (close range), the interaction energy scales as 1/Z 3 with the atom-wall distance Z, while for atom-wall distances large in comparison to a typical atomic wavelength, the interaction energy scales as 1/Z 4 (see Chap. 8 of Ref.[9]). The leading term is given by virtual dipole transitions, while multipole corrections have recently been analyzed in Ref. [10]. The symmetry breaking induced by the wall leads to dipole-quadrupole mixing terms, which lead to admixtures to metastable levels [11,12]. While this effect has been analyzed in the non-retarded van-der-Waals regime [11,12], a fully quantum electrodynamic calculation of this effect would be of obvious interest. This fact is emphasized by the curious observation of a long-range, and conceivably super-long-range (micrometer-scale) interaction of metastable hydrogen 2S atoms with a conducting surface (the so-called Sokolov effect, see Refs. [13][14][15][16]). It is not far-fetched to suspect that this effect could be due to a quantum electrodynamically induced tail of the dipole-quadrupole mixing term in the atom-wall interaction. Namely, for the hydrogen 2S atom, the neighboring 2P 1/2 and 2P 3/2 levels are removed only by the Lamb shift and finestructure, respectively, while it is known that virtual states of lower energy can induce long-range tails in atomwall interactions, as well as in the Lamb shift between plates (see Refs. [17][18][19][20][21][22][23][24][25][26]). The large admixtures typically induced in atomic systems when a metastable level couples to nearly degenerate states of opposite parity suggest that a closer investigation of the hydrogen system is warranted. Atomic units with = 4πǫ 0 = 1 and c = 1/α are used throughout this Rapid Communication, where α is the fine-structure constant. The electron charge is explicitly denoted as e unless stated otherwise.Retardation of the atom-wall interaction.-The quan-

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Section: −4mentioning

confidence: 99%

“…(11)] gradually become important. [These are obtained by straightforward expansion of the potential (11).] Numerically determined admixtures of the coupled |S 1/2 are given in Fig.…”

Section: −4mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Long-range atom-wall interactions and mixing terms: Metastable hydrogen

Jentschura

2015

Phys. Rev. A

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“…Some time ago, transmission through narrow channels [4] and level shifts in closed or semi-infinite cavities [5,6] have been studied. Recently, inelastic electronic transitions on passage over a metal edge [7] and reflection from surfaces and (reflection) gratings [8] have been measured. Currently there is great interest in these potentials, in particular for metastable helium which is widely used in atom optics [9] as well as in surface physics [10] and for which Bose-Einstein condensation has recently been achieved [11].…”

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The van der Waals potential between metastable atoms and solid surfaces: Novel diffraction experimentsvs.theory

Bruehl¹,

Fouquet²,

Grisenti³

et al. 2002

Europhys. Lett.

109

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Highly polarizable metastable He* (2 3 S) and Ne* (2 3 P) atoms have been diffracted from a 100 nm period silicon nitride transmission grating and the van der Waals coefficients C3 for the interaction of the excited atoms with the silicon nitride surface have been determined from the diffraction intensities out to the 10th order. The results agree with calculations based on the non-retarded Lifshitz formula.PACS numbers: 34.50.Dy, 03.75.BeThe van der Waals (vdW) force between atoms, molecules and solid surfaces is of far reaching importance in many branches of physics, chemistry, and biology [1]. For larger distances, retardation due to the exchange of virtual photons has to be included, while for distances much smaller than the smallest wavelength a non-retarded approach can be used. The theoretical foundations for atom-surface interactions were laid in the pioneering work of Lifshitz [2]. In this case the non-retarded vdW potential has the form −C 3 /l 3 in leading order, where l is the atom-surface separation and C 3 depends on the atom, its electronic state, and on the electronic states of the solid.For groundstate rare gas atoms the C 3 coefficients have recently been measured with good accuracy [3]. Less is known about the van der Waals interactions of electronically excited metastable and Rydberg atoms, in particular the C 3 coefficient is not accurately known. Some time ago, transmission through narrow channels [4] and level shifts in closed or semi-infinite cavities [5,6] have been studied. Recently, inelastic electronic transitions on passage over a metal edge [7] and reflection from surfaces and (reflection) gratings [8] have been measured. Currently there is great interest in these potentials, in particular for metastable helium which is widely used in atom optics [9] as well as in surface physics [10] and for which Bose-Einstein condensation has recently been achieved [11]. The atom-surface van der Waals potentials could soon become relevant in guiding slow metastable rare gas atoms along microstructures [12] or in studying collective effects of Bose-Einstein condensed metastable He* atoms in contact with a surface.From a theoretical point of view atoms in excited states are of particular interest. Their polarizability α is expected to increase as n 7 , with correspondingly much stronger interactions [13]. Therefore it is not obvious whether approximate formulae for the groundstate atom-surface vdW potential are still applicable for excited atoms. Moreover, with the much stronger vdW interaction new effects such as higher multipole coefficients [14] can be expected.In this article, an effective but simple experimental method is used to determine the atom-surface vdW coefficient C 3 for metastable rare gas atoms. It is based on diffraction of an atomic beam from a nanostructured transmission grating with a period of only 100 nm. Modifications in the hierarchy of the intensities of the higher order maxima in the diffraction pattern have been shown to be directly related to the strength C 3 of the atom...

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Fulfilling causality: two numerical techniques for accurately computing the propagation of independent laser beams through a nonlinear medium

Perrin

Gil²,

Lippi³

2005

Appl. Phys. B

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7 pagesWe identify the origin of some numerical difficulties related to causality which appear in the simulation of transport equations. Two numerical techniques are presented for the integration of models describing counter-propagating laser beams in interaction with a nonlinear medium. One, based on the characteristic method, rests on the transport properties of first-order derivatives and is able to propagate a signal in a linear non-dispersive medium without any deformation. The other, fully explicit, directly handles both first and second order derivatives. Both numerical schemes are applied to a physical example

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Atom Symmetry Break and Metastable Level Coupling in Rare Gas Atom-Surface van der Waals Interaction

Cited by 30 publications

References 11 publications

Long-range atom-wall interactions and mixing terms: Metastable hydrogen

Long-range atom-wall interactions and mixing terms: Metastable hydrogen

The van der Waals potential between metastable atoms and solid surfaces: Novel diffraction experimentsvs.theory

Fulfilling causality: two numerical techniques for accurately computing the propagation of independent laser beams through a nonlinear medium

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