  Particle physics has for some time made extensive use of extended field
configuations such as solitons, instantons, and sphalerons. However, no direct
use has yet been made of the quite extensive literature on ``localized wave''
configurations developed by the engineering, optics, and mathematics
communities. In this article I will exhibit a particularly simple ``physical
wavelet'' -- it is a Lorentz covariant classical field configuration that lives
in physical Minkowski space. The field is everwhere finite and nonsingular, and
has quadratic falloff in both space and time. The total energy is finite, the
total action is zero, and the field configuration solves the wave equation.
These physical wavelets can be constructed for both complex and real scalar
fields, and can be extended to the Maxwell and Yang-Mills fields in a
straightforward manner. Since these wavelets are finite energy, they are
guaranteed to be classically present at finite temperature; since they are zero
action, they can contribute to the quantum mechanical path integral at zero
``cost''.
