First-Order Dispersion Forces

Abstract

The interaction energy between two atoms, one of which is excited, is investigated. The form of the interaction depends on the relation between the distance R separating the atoms and the wavelength k1—1 of the transition from the ground state to the excited state. If k1R<1 the photon may be trapped between the two atoms leading to the well-known dipole—dipole interaction. If k1R>1 the interaction is small, the state of the interacting atoms is not a stationary state and the photon is emitted after a time determined by the spontaneous emission probability.

Quantum entanglement and disentanglement of multi-atom systems

“…The effect of Ω 12 on the atomic system is the shift of the energy of the single excitation collective states from the single-atom energy. The collective parameters are given by the expressions [19][20][21][22][23]71] …”

Atmospheric water droplets can catalyse atom pair break-up via surface-induced resonance repulsion

“…Two identical atoms, one isotropically excited and the other in its ground state, can be bound together in free space due to an attractive retarded resonance interaction [1][2][3][4]. Interestingly, the same retarded resonance interaction can influence the binding energy of atom pairs [5,6].…”

“…While the symmetric state will quickly decay into two ground-state atoms, the antisymmetric state can be quite long-lived. The system can thus be trapped in the antisymmetric state [1,3]. The energy migrates back and forth between the two atoms until either the two atoms move apart or a photon is emitted away from the system.…”

“…We first recall the standard argument [1,3,4]: Consider two identical atoms where one initially is in its ground state and the other is in an excited state. This state can also be represented by a superposition of states: one symmetric and one antisymmetric with respect to interchange of the atoms.…”

Enlarged molecules from excited atoms in nanochannels

“…While the symmetric state is likely to decay into two ground-state atoms, the antisymmetric state can be quite long-lived. The system can thus be trapped in the antisymmetric state [4,8]. The energy migrates back and forth between the two atoms until either the two atoms move apart or a photon is emitted away from the system.…”