Re:Quantum researchers able to split one photon into three
by lisper on Sunday March 01, 2020 @05:10PM
(#22459718)
I presume you meant to ask:
If you produce 2 entangled photons, and then split one of them again, do you end up with three mutually-entangled photons?
The answer to that is: yes.
The next obvious question then is: what then is the big deal about producing three mutually entangled photons? And the answer to that is that spontaneous parametric down conversion is very sensitive to the wavelength/frequency of the input light. You can't just throw in any old photon and split it. It has to be a very specific wavelength for the process to work, so as a practical matter it is nearly impossible to do the two-step process that you've asked about.
If you produce 2 entangled photons, and then split one of them again, do you end up with three mutually-entangled photons?
The answer to that is: yes.
The next obvious question then is: what then is the big deal about producing three mutually entangled photons? And the answer to that is that spontaneous parametric down conversion is very sensitive to the wavelength/frequency of the input light. You can't just throw in any old photon and split it. It has to be a very specific wavelength for the process to work, so as a practical matter it is nearly impossible to do the two-step process that you've asked about.