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Coherent state between a fermion and a photon 
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#1
Sep1613, 12:01 AM

P: 54

Can we have a coherent state between a fermion and a photon! I mean can there ever be a fermionic polariton?



#2
Sep1613, 04:16 AM

P: 231

You may have to clarify your question a bit. Imagine a simple atomic system with one electron in a magnetic field. The photon can interact with the system by flipping the electrons spin from down to up, total change of spin by 1, but the electron remains a fermion. What situation were you thinking of? What part of the system should be fermionic?



#3
Sep1613, 07:30 AM

P: 54

Thank you Zarqon for replying, I did some search and got my answer.
The Wiki page says :"The polariton is a bosonic quasiparticle, and should not be confused with the polaron, a fermionic one, e.g. an electron plus attached phonon cloud. ". Precisely something I was looking for, if you are still interested we can discuss 


#4
Sep1613, 08:43 AM

Sci Advisor
P: 3,633

Coherent state between a fermion and a photon
Note also that you cannot have a superposition of states with an even and odd number of fermions.
This is calles univalence superselection rule. It is easiest to see from the fact that such a superposition is not invariant (not even up to a phase) under a rotation by 2π. 


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