429 research outputs found
Approximate symmetries of long-range Rydberg molecules including spin effects
An operator that generates an approximate symmetry of long-range Rydberg
molecules (LRRMs) formed by two alkali atoms, one in a Rydberg state and the
other in the ground state, is identified. This is first done by evaluating the
natural orbitals associated to a variational calculation of the binding wave
function within the Born-Oppenheimer description of the molecule including
and Fermi pseudopotential and the hyperfine structure energy terms. The
resulting orbitals with highest occupation number are shown to be identical to
those obtained by a perturbative model for high angular momentum -- trilobite
and butterfly -- LRRMs. Whenever the slight dependence of the quantum defects
of the Rydberg electron on its total momentum
can be neglected, the symmetry operator of the high angular momentum LRRMs
orbitals is identified as the sum of the spin of the Rydberg electron , spin of the valence electron and the spin of nucleus
of the ground state atom, . The
spin-orbitals that diagonize define compact basis sets for the
description of LRRMs beyond the aforementioned approximations. The matrix
elements of the Hamitonian in these basis sets have simple expressions, so that
the relevance of triplet and singlet contributions can be directly estimated.
The expected consequences of this approximate spin-symmetry on the spectra of
LRRMs are briefly described.Comment: 24 pages, 13 figure
Entanglement enhancement and postselection for two atoms interacting with thermal light
The evolution of entanglement for two identical two-level atoms coupled to a
resonant thermal field is studied for two different families of input states.
Entanglement enhancement is predicted for a well defined region of the
parameter space of one of these families. The most intriguing result is the
possibility of probabilistic production of maximally entangled atomic states
even if the input atomic state is factorized and the corresponding output state
is separable.Comment: accepted for publication in J. Phys.
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