Related papers: The ubiquitous flavor pendulum
Even in the absence of neutrino masses, a neutrino gas can exhibit a homogeneous flavor instability that leads to a periodic motion known as the fast flavor pendulum. A well-known necessary condition is a crossing of the angular flavor…
Neutrinos in core-collapse supernovae and neutron-star mergers are susceptible to flavor instabilities of three kinds: slow, fast, and collisional. Prior work has established mappings of the first two onto abstract mechanical systems in…
A dense neutrino plasma can exhibit collective flavor evolution caused by neutrino--neutrino refraction. Recently, a new class of exact nonlinear inhomogeneous solutions was discovered: single-wave (SW) solutions of the fast flavor system.…
In compact astrophysical objects, the neutrino density can be so high that neutrino-neutrino refraction can lead to fast flavor conversion of the kind $\nu_e \bar\nu_e \leftrightarrow \nu_x \bar\nu_x$ with $x=\mu,\tau$, depending on the…
In core-collapse supernovae or compact binary merger remnants, neutrino-neutrino refraction can spawn fast pair conversion of the type $\nu_e \bar\nu_e \leftrightarrow \nu_x \bar\nu_x$ (with $x=\mu, \tau$), governed by the angle-dependent…
Neutrino-neutrino interactions can lead to collective flavour conversion effects in supernovae and in the early universe. We demonstrate that the case of "bipolar" oscillations, where a dense gas of neutrinos and antineutrinos in equal…
We construct a simple example for self-induced flavor conversion in dense neutrino gases showing new solutions that violate the symmetries of initial conditions. Our system consists of two opposite momentum modes 1 and 2, each initially…
Collective oscillations in dense neutrino gases (flavor waves) are notable for their instabilities that cause fast flavor conversion. We develop a quantum theory of interacting neutrinos and flavor wave quanta, which are analogous to…
Dense clouds of neutrinos and antineutrinos can exhibit fast collective flavor oscillations. Previously, in Phys. Rev. Lett. 126 (2021) 061302, we proposed that such flavor oscillations lead to depolarization, i.e., an irreversible mixing…
We identify in the flavor transformation of astrophysical neutrinos a new class of phenomena, a common outcome of which is the suppression of flavor conversion. Appealing to the equivalence between a bipolar neutrino system and a gyroscopic…
We consider a dense neutrino gas in the "fast-flavor limit" (vanishing neutrino masses). For the first time, we identify exact solutions of the nonlinear wave equation in the form of solitons. They can propagate with both sub- or…
The flavor evolution of a neutrino gas can show ''slow'' or ''fast'' collective motion. In terms of the usual Bloch vectors to describe the mean-field density matrices of a homogeneous neutrino gas, the slow two-flavor equations of motion…
Oscillations of neutrino emerging from a supernova core are studied. In this extremely high density region neutrino self interactions induce collective flavor transitions. When collective transitions are decoupled from matter oscillations,…
In an interacting neutrino gas, flavor coherence becomes dynamical and can propagate as a collective mode. In particular, tachyonic instabilities can appear, leading to "fast flavor conversion" that is independent of neutrino masses and…
In neutrino-dense astrophysical environments, these particles exchange flavor through a coherent weak field, forming a collisionless neutrino plasma with collective flavor dynamics. Instabilities, which grow and affect the environment, may…
A dense neutrino medium can experience collective flavor oscillations through nonlinear neutrino-neutrino refraction. To make this multi-dimensional flavor transport problem more tractable, all existing studies have assumed certain…
Despite their feeble interactions, dense astrophysical neutrinos can behave collectively, exchanging flavor through waves of the neutrino plasma. Can collective interactions also induce pairing instabilities and reorganize the neutrino…
We study the fully nonlinear fast flavor evolution of neutrinos in 1+1 dimensions. Our numerical analysis shows that at late time the system reaches an approximately steady state. Using the steady state approximation we analytically show…
In dense neutrino systems, such as found in the early Universe, or near a supernova core, neutrino flavor evolution is affected by coherent neutrino-neutrino scattering. It has been recently suggested that many-particle quantum entanglement…
Supernova neutrinos can exhibit a rich variety of flavor conversion mechanisms. In particular, they can experience "fast" self-induced flavor conversions almost immediately above the core. Very recently, a novel method has been proposed to…