  A remarkable feature of atomic ground states is that they are observed to be
radiationless in nature, despite (from a classical viewpoint) typically
involving charged particles in accelerated motions. The simple hydrogen atom is
a case in point. This universal groundstate characteristic is shown to derive
from particle-vacuum interactions in which a dynamic equilibrium is established
between radiation emission due to particle acceleration, and compensatory
absorption from the zero-point fluctuations of the vacuum electromagnetic
field. The result is a net radiationless ground state. This principle
constitutes an overarching constraint that delineates an important feature of
quantum ground states.
