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I have been wondering the relation between Higgs BEC and Higgs field. During reheating of the universe, people always claim the energy density of inflaton drops down like massive particles without pressure. So that energy can be interpreted as inflaton condensate. But are they really the same thing? For a scalar field in general, there is potential energy. Can we always say the energy in the potential energy belongs to the condensate?

A remotely relevant question is, what's the relation between photons and classical electromagnetic field? Do photon, W/Z boson in SM condense?

Qmechanic
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larueroad
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  • About photons, this question already has an answer: https://physics.stackexchange.com/q/19127/154997. About W and Z, they decay too fast to have a chance to condense. –  Jun 08 '17 at 08:38
  • When inflaton oscillates near potential walls, kinetic energy is negligible (thus 0 momenta), and amplitude of oscillations is decaying slowly. Equation of state is then defined by the potential. What is the issue with potential energy you're having? – Kosm Jun 08 '17 at 13:30
  • During slow-roll inflation, the energy density is almost constant while the universe undergoes exponential expansion. If the condensate picture works for inflaton, doesn't it mean inflaton particles are constantly produced due to the increase of volume? Or how to make sense of the negative pressure of inflaton in the condensate picture? – larueroad Jun 08 '17 at 18:15
  • @karlzr 1) during inflation you cannot use condensate picture since pressure is nonzero. 2) It's not particles that drive inflation but a field. Inflaton particles are created during coherent oscillation of the field. – Kosm Jun 09 '17 at 09:49
  • energy is not conserved in GR (only locally conserved).
    • – Kosm Jun 09 '17 at 10:53
  • @Kosm So now I guess I have an answer to my question: BEC of Higgs particles and Higgs field are different things. But condensate of a scalar particles can be produced at coherent oscillation of the scalar field, like inflaton during reheating. Is it right? Is the inflaton condensate during reheating BEC? – larueroad Jun 09 '17 at 21:05
  • effectively, yes – Kosm Jun 09 '17 at 23:04