Quantum interference effect for two atoms excited by molecular photodissociation : a theoretical analysis

Grangier, Philippe; Vigué, J.

doi:10.1051/jphys:01987004805078100

Cited by 7 publications

(2 citation statements)

References 17 publications

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“…The second is the evolution of the excited molecular state into distant fragments. The third one is the radiative decay which occurs long after the dissociation has taken place at distances (vτ ) of the order of 10 −5 m far larger than the fluorescence wavelength (121 nm), more the fluorescence detection is time averaged so no interference of Grangier type can be seen [25]. For the doubly excited molecular states, dissociation is very fast compared to rotation, and yields high kinetic energy fragments, so that the axial recoil approximation has to be valid.…”

Section: Photodissociation Fragment Alignmentmentioning

confidence: 99%

Photodissociation of doubly excited states of molecular hydrogen studied by polarization measurement of Lyman-α fluorescence

Glass‐Maujean

Kneip

Flemming

et al. 2005

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

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The polarization anisotropy of Lyman-α fluorescence in the photodissociation of the doubly excited states of H2 has been measured in the 27–38 eV energy range. It has been calculated taking into account the dissociation probabilities of the various molecular states involved in the process and the depolarization due to collisional effects. The agreement between experiment and theory is very good; it shows the importance of interferences and gives confidence in the analysis of the process. The fluorescence polarization anisotropy has been calculated classically in the case of a dissociation leading to H(2pπ) + H(2pσ) excited fragments.

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Section: Photodissociation Fragment Alignmentmentioning

confidence: 99%

Photodissociation of doubly excited states of molecular hydrogen studied by polarization measurement of Lyman-α fluorescence

Glass‐Maujean

Kneip

Flemming

et al. 2005

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

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“…For the case of two two-level atoms such dark states are well known and have been confirmed experimentally decades ago [11]. A generic dark state can then be written as in Eq.…”

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confidence: 85%

Subradiance via Entanglement in Atoms with Several Independent Decay Channels

et al. 2017

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Spontaneous emission of a two-level atom in free space is modified by other atoms in its vicinity leading to super-and subradiance. In particular, for atomic distances closer than the transition wavelength the maximally entangled antisymmetric superposition state of two individually excited atomic dipole moments possesses no total dipole moment and will not decay spontaneously at all. Such a two-atom dark state does not exist, if the atoms feature additional decay channels towards other lower energy states. However, we show here that for any atomic state with N − 1 independent spontaneous decay channels one can always find a N -particle highly entangled state, which completely decouples from the free radiation field and does not decay. Moreover, we show that this state is the unique state orthogonal to the subspace spanned by the lower energy states with this property. Its subradiant behavior largely survives also at finite atomic distances. The decay of an excited atomic state towards lower lying states via spontaneous emission is one of the most striking consequences of the quantum nature of the free radiation field [1]. Heuristically introduced even before e.g. by Einstein, the spontaneous emission rate Γ = Interestingly, it turns out that for several particles the emission process is not independent but can be collectively enhanced or reduced depending on the atomic arrangement [3]. It was already noted some time ago that these superradiant and subradiant collective states, where a single excitation is distributed over many particles, are entangled atomic states [4,5]. Although a recent classical coupled dipole model also leads to subradiancelike phenomena [6], the most superradiant and the perfect dark states for two two-level atoms with states (|g , |e ) are the maximally entangled symmetric and antisymmetric dipole moment superposition statesWhile superradiance on a chosen transition persists in the case, when the atom possesses more than one decay channel, there is no completely dark state for two multilevel atoms with several decay channels from a single excited state |e to several lower lying states |g i as schematically depicted in Fig. 1. Hence, in practise the observation of subradiant states is much more difficult than seeing superradiance, as all other decay channels need to be excluded [7].In this paper, we introduce a new class of subradiant or dark states appearing for atoms with several independent transitions. As a key result of this work we find that for systems of N particles one can construct highly * Laurin.Ostermann@uibk.ac.at multi-partite entangled states, where all N − 1 independent decay channels are suppressed. For these states the total dipole moments on all of these N − 1 transitions simultaneously vanish and at least in principle the optical excitation in this state will be stored indefinitely.After introducing our model atom system and the generalized, unique multi-atom dark states, we will discuss their special entanglement properties and possible quantum information processing...

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Superradiance of trapped atoms

Protsenko

2006

J Russ Laser Res

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Quantum interference effect for two atoms excited by molecular photodissociation : a theoretical analysis

Cited by 7 publications

References 17 publications

Photodissociation of doubly excited states of molecular hydrogen studied by polarization measurement of Lyman-α fluorescence

Photodissociation of doubly excited states of molecular hydrogen studied by polarization measurement of Lyman-α fluorescence

Subradiance via Entanglement in Atoms with Several Independent Decay Channels

Superradiance of trapped atoms

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