Transport theory of massless fields
- Soltan Institute for Nuclear Studies, ul. Hoza 69, PL-00-681 Warsaw (Poland)
Using the Schwinger-Keldysh technique we discuss how to derive the transport equations for the system of massless quantum fields. We analyze the scalar field models with quartic and cubic interaction terms. In the {phi}{sup 4} model the massive quasiparticles appear due to the self-interaction of massless bare fields. Therefore, the derivation of the transport equations strongly resembles one of the massive fields, but the subset of diagrams which provides the quasiparticle mass has to be resummed. The kinetic equation for the finite width quasiparticles is found, where, except for the mean-field and collision terms, there are terms which are absent in the standard Boltzmann equation. The structure of these terms is discussed. In the massless {phi}{sup 3} model the massive quasiparticles do not emerge and presumably there is no transport theory corresponding to this model. It is not surprising since the {phi}{sup 3} model is, in any case, ill defined. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 538665
- Journal Information:
- Physical Review, D, Vol. 56, Issue 4; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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