  It is shown that, for a harmonic oscillator in the ground state, Bohmian
mechanics and quantum mechanics predict values of opposite sign for certain
time correlations.
  The discrepancy can be explained by the fact that Bohmian mechanics has no
natural way to accomodate the Heisenberg picture, since the local expectation
values that define the beables of the theory depend on the Heisenberg time
being used to define the operators.
  Relations to measurement are discussed, too, and shown to leave no loophole
for claiming that Bohmian mechanics reproduces all predictions of quantum
mechanics exactly.
