The evolution of quantal uncertainties in at most quadratic potentials
  We investigate the time evolution of momentum and position uncertainties for wave packets of arbitrary shape in at most quadratic potentials. We consider all possible cases of potentials and initial conditions. Doing so we see that the mixed uncertainty and for Gaussian wave packets moreover the chirp are convenient and important tools to identify the characteristic features of uncertainty dynamics. Special attention is given to the spreading and narrowing of wave packets. 
Natascha Riahi
quant-ph