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On equivalence of QFT and Quantum Statistical Physics 
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#1
May1709, 08:52 AM

P: 79

Does fact that QFT in imaginary time is equivalent to QSP represents the proof that manyparticle quantum physics is equivalent to quantum theory of fields?
To elaborate a little, I had some discussion with some engineers, and when I was explaining them Standard Model I had to invoke concepts of quantum fields and they immediately turned their noses in despise to "overly abstract" concept. Since they didn't have problems with quantum particles and statistical physics I've thought of taking the route starting from manyparticle quantum physics but I'm not sure that I can do that because I'm not certain how to treat equivalence of imaginary time with temperature. I mean, parameter t in QFT enters from spacetime structure but parameter [tex]\beta[/tex] is inserted in partition function only to be shown after calculation, what is it's connection with kinetic energy. In Minkowski space timecomponent of energymomentum is energy but I cannot find any formal transformation which would transform it into median kinetic energy at corresponding temperature. 


#2
May1709, 01:49 PM

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Why cast pearls before the swine ? ;)
Why is the quantum field more abstract than the classical field of let's say electromagnetism? 


#3
May1709, 03:13 PM

P: 79




#4
May1709, 03:14 PM

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On equivalence of QFT and Quantum Statistical Physics
But the fields in Statistical Field Theory is i) not particles and ii) one often use nonrelativistic field theory.



#5
May1809, 10:01 PM

P: 969

I just wanted to point out that there is another way to derive thermal quantum field theory from quantum field theory other than the imaginarytime formalism. There is also the realtime formalism which is more intuitive  an operator based approach rather than pathintegral. Of course pathintegrals make everything easier, but sometimes you lose the physics if your view is to compare imaginary time in the path integral to inverse temperature and the partition function.



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