Conservation Laws and Quantum Measurement. (arXiv:1803.02687v1 [quant-ph])

Because quantum measurements have probabilistic outcomes they appear to
violate conservation laws in individual experiments. In this note some simple
examples are used to show that when pre-existing entanglement relations of the
measured system are taken into account, quantities such as momentum, energy,
and angular momentum can be strictly conserved, despite appearances to the
contrary. The relationship between conservation laws and measurement processes
is then framed in more general terms. I close with a discussion of the possible
consequences for various views on the fundamental nature of quantum measurement

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