Abstract: | Heisenberg's position-measurement-momentum-disturbance relation is derivable from the uncertainty relation (q) (p) h/2 only for the case when the particle is initially in a momentum eigenstate. Here I derive a new measurement-disturbance relation which applies when the particle is prepared in a twin-slit superposition and the measurement can determine at which slit the particle is present. The relation is d × p 2h/ , where d is the slit separation and p = DM(Pf, Pi) is the Monge distance between the initial Pi(p) and final Pf(p) momentum distributions. |