Turbulence fingerprint on collective oscillations of supernova neutrinos

Abstract

We bring to light a novel mechanism through which turbulent matter density fluctuations can induce collective neutrino flavor conversions in core-collapse supernovae, i.e., the leakage of flavor instabilities between different Fourier modes. The leakage mechanism leaves its notable fingerprint on the flavor stability of a dense neutrino gas by coupling flavor conversion modes on different scales which in turn, makes the flavor instabilities almost ubiquitous in the Fourier space. This intriguing phenomenon arises from the fact that unlike the case of collective neutrino oscillations in a homogenous medium, the neutrino flavor conversion modes depend linearly on each other at different supernova zones in a turbulent medium. The most remarkable consequence of this effect is in that it allows for the presence of significant flavor conversions in the deepest supernova regions even in the absence of the so-called fast modes. This is yet another crucial impact of turbulence on the physics of core-collapse supernovae which can profoundly change our understanding of neutrino flavor conversions in the supernova environment.