  An analysis of the quantum breathing behavior of few-particle Coulomb systems
in one- and two-dimensional harmonic traps is presented. We report the
existence of \emph{two independent breathing modes} and present exact numerical
results for two particles at any coupling strength which smoothly connect the
two known limits of an \emph {ideal} quantum and a strongly coupled \emph
{classical} system. Substantial differences in the breathing frequency of
two-dimensional fermions and bosons are observed which may be used as a
sensitive experimental tool to probe confined interacting quantum systems.
