No-cloning and stimulated emission

[Demystifier]

So one time out of three stimulated emission produces a V photon from an H photon? Does this mean the textbook treatment of stimulated emission is only true in two out of three times?

Yes, that's probably the simplest way to understand why stimulated emission does not allow perfect cloning. In an attempt of cloning there is always some probability for an error, even if a very small one. But imperfect cloning which tollerates an error is, of course, possible.

 

[greypilgrim]

Do we need QFT to prove this? I guess so, since photons are described by QFT.

Interestingly though, the proof of the general no-cloning theorem only uses Hilbert space properties and doesn't need special relativity.

 

[bhobba]

Do we need QFT to prove this? I guess so, since photons are described by QFT.

I think its more that in QFT particle numbers are not fixed so its required to explain particle creation.

This is actually a deep requirement of combining relativity and QM. See:
https://www.amazon.com/dp/019969933X/?tag=pfamazon01-20

It has a chapter giving the gory mathematical detail - contour integration and all.

Thanks
Bill