Effects of zero-point energy in elementary-system interactions

Abstract

The effects of zero-point energy, in comparison with those of excitation energy, are investigated by studying the behavior of two coupled harmonic oscillators for four types of coupling: rotating-wave coupling, counterrotating wave coupling, dipole-dipole (or dipole-field) coupling, and elastic-attraction coupling. It is found that in all but the rotating-wave coupling case, which has only slowly varying terms in the interaction Hamiltonian, the initiation of coupling between ground-state oscillators is followed by an oscillating energy increase in both oscillators at the expense of the coupling energy. In the same three cases, the ground state of the coupled system has a lower zero-point energy than the energy of the state in which the individual oscillators are in their ground states, thus leading to the presence of a van der Waals attraction. This result motivates the conclusion that only the rapidly varying terms in the interaction Hamiltonian are responsible for the attraction. The energies of the individual oscillators while the coupled system is in its ground state are calculated. In the van der Waals cases, these energies turn out to be greater than the zero-point energies of the individual oscillators. A physical explanation for the increase is offered. The feasibility of the utilization or absorption of zero-point energy is discussed.