MODULATIONAL INSTABILITIES IN NEUTRINO-ANTINEUTRINO INTERACTIONS
Marklund M., Shukla P.K., Betschart G., Stenflo L., Anderson D., Lisak M.

Received: February 13, 2004

PACS: 13.15.+g, 14.60.Lm, 97.10.Cv, 97.60.Bw

DJVU (453.5K)

PDF (1975.2K)

Using a semiclassical approach, we analyze the collective behavior of neutrinos and antineutrinos in a dense background. Applying the Wigner transform technique, we show that the interaction can be modeled by a coupled system of nonlinear Vlasov-like equations. From these equations, we derive a dispersion relation for neutrino-antineutrino interactions on a general background. The dispersion relation admits a novel modulational instability. Moreover, we investigate the modifications of the instability due to thermal effects. The results are examined, together with a numerical example, and we discuss the induced density inhomogeneities using parameters relevant to the early Universe.