Extending Heisenberg's Measurement-Disturbance Relation to the Twin-Slit Case

Heisenberg's position-measurement-momentum-disturbance relation is derivable from the uncertainty relation σ(q)σ(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 × Δp ≥ 2h/π, where d is the slit separation and Δp = DM(Pf, Pi) is the Monge distance between the initial Pi(p) and final Pf(p) momentum distributions.