whether there is/could be a way to tell if an entangled particle has been/has not been collapsed without collapsing it in the process

21 views
0

whether there is/could be a way to tell if an entangled particle has been/has not been collapsed without collapsing it in the process

In: 0

Inherently no. Any attempts at observing any properties of the particle will collapse the wave function. So as far as we know there is no ability to detect if a particle is entangled or have been collapsed without collapsing it in the progress. This is actually done today with quantum encryption where the two parties detect if the particle have been collapsed by an intermediary party, but they do collapse the wave functions in this process and use the resulting random data as an encryption key in more standard symmetric encryption. We might find some sort of clever way to get around the currently known limitations in the future, maybe there are papers out on this currently that I do not know of.

There is such a thing as quantum error correction. You can tell if your wavefunction has collapsed or (more precisely) *decohered* (lost purity), by measureing *some* of its properties and making appropriate adjustments. You just need to make sure that your measurement only concerns properties you don’t care about.