Towards a measurement theory in QFT: "Impossible" quantum measurements are possible but not ideal
Towards a measurement theory in QFT: "Impossible" quantum measurements are possible but not ideal
Naive attempts to put together relativity and quantum measurements lead to signaling between space-like separated regions. In QFT, these are known as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow class="MJX-TeXAtom-ORD"><mml:mtext class="MJX-tex-mathit" mathvariant="italic">impossible measurements</mml:mtext></mml:mrow></mml:math>. We show that the same problem arises in non-relativistic quantum physics, where joint nonlocal measurements (i.e., between systems kept spatially separated) in …