Violation of Heisenberg's error-disturbance uncertainty relation in neutron spin measurements

Understand

In its original formulation, Heisenberg's uncertainty principle dealt with the relationship between the error of a quantum measurement and the thereby induced disturbance on the measured object.

• Meanwhile, Heisenberg's heuristic arguments have turned out to be correct only for special cases.
• A new universally valid relation was derived by Ozawa in 2003.
• Here, we demonstrate that Ozawa's predictions hold for projective neutron-spin measurements.