A Are Quantum Measurements Truly Special Cases of Unitary Operators?

Heidi
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Hi Pfs

I read this answer in
https://quantumcomputing.stackexcha...-gates-must-be-unitary-what-about-measurement

Quantum measurements are special cases of quantum channels (CPTP cards). Stinespring dilation states that any quantum channel is realized by partially tracing a unitary operator acting on a possibly larger Hilbert space.

I wonder if it is true. and in this case is it possible to give an example of such unitary operator? i suppose that the evolution process is random.

[I translated the French part. Please use English only.]
 
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