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Classical and quantum fields

  1. Jan 22, 2012 #1
    how we can differentiate classical and quantum fields?i searched everywher..but i did not get a satisfactory answer
     
  2. jcsd
  3. Jan 22, 2012 #2
    In QFT the fields are operators that obey a commutation relation.
     
  4. Jan 22, 2012 #3
    electromagnetic field is a classical field or quantum field?in quantum we speak in erms of photons....if we go for second quantisation to electromagnetic field what we will get??
     
  5. Jan 23, 2012 #4
    Um... there is a Lagrangian that gives the electromagnetic field, working with this field classically one obtains a classical field theory (Maxwell's equations, etc.), if one instead applies canonical quantization to this Lagrangian one gets a quantum field theory (Quantum Electrodynamics). Second quantization IS quantum field theory, the excitations in this case are photons.
     
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