Causality in field emission from an atomic dipole: Schrödinger picture approach
P. R. Berman · Physical Review A · 2004
The change in the average value of the electric field and of the electric field squared following excitation of an atomic dipole is calculated using a density matrix approach in the Schr\"odinger picture. It is shown that field emission is perfectly causal provided non-energy-conserving terms are included. The Schr\"odinger picture approach offers some advantages over the conventional Heisenberg picture approach.