Correlations between detectors allow violation of the Heisenberg   noise-disturbance principle for position and momentum measurements
  Heisenberg formulated a noise-disturbance principle stating that there is a tradeoff between noise and disturbance when a measurement of position and a measurement of momentum are performed sequentially, and another principle imposing a limitation on the product of the uncertainties in a joint measurement of position and momentum. We prove that the former, the Heisenberg sequential noise-disturbance principle, holds when the detectors are assumed to be initially uncorrelated from each other, but that it can be violated for some properly correlated initial preparations of the detectors. 
Antonio Di Lorenzo
quant-ph cond-mat.mes-hall cond-mat.stat-mech