- Summary
- A possible experiment in which the uncertainty principle seems not to apply?

I am not too knowledgable about QM, so please forgive me if this is a dumb question. I have outlined below an experiment setup for which Heisenberg's uncertainty principle seems not to apply:

- Imagine a particle for which we wish to collect the exact position and velocity. We have a detector d1 at which the particle is fired. The detector is at an acute angle to the path of the particle so little velocity is lost in the collision. Detector d1 collects the exact position of the particle (but not velocity).
- After the particle has collided with detector d1, it is deflected and hits detector d2. Detector d2 collects the exact velocity of the particle (but not position).
- As the angle between detector d1 and the particle’s initial course is acute, we therefore have an approximate velocity for the particle at detector d1 - the velocity measured at detector d2. Further, we can make the angle between detector d1 and the particle’s initial course as acute as we wish leading to a corresponding increase in the accuracy of the velocity estimate.
- So in summary, by making the deflection angle arbitrarily small, the velocity of the particle can be determined to arbitrarily precision. The particle’s position is known to arbitrary precision, so it seems the uncertainty principle does not always hold.