Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli(意大利国家核物理研究所(INFN)那不勒斯分部);Deutsches Elektronen-Synchrotron DESY(德国电子同步加速器研究中心);Max-Planck-Institut für Physik(马克斯·普朗克物理研究所)
A system of classical interacting spins can develop collective instabilities which, in the nonlinear regime, mimic the motion of a gyroscopic pendulum. Known as the flavor pendulum, this behavior appears among the collective modes of a dense neutrino plasma after a strong reduction of phase space through symmetry assumptions. It has been identified in homogeneous slow and fast flavor systems and, most recently, in single-wave solutions of the fast system. We explain the reasons for its ubiquitous appearance. We show that a system of three classical spins must always be pendular, or only two in the presence of an external field. Furthermore, such a system always defines a continuum of vectors with time-independent length. If these are identified as interacting spins, they immediately lead to the continuum cases of slow and fast flavor pendula. As another new insight, any of these spins can be chosen as the pendulum, periodically exchanging flavor with the rest of the system.
Single-wave solutions of the neutrino fast flavor system. Part I. Mechanical properties
Deutsches Elektronen-Synchrotron DESY(德国电子同步加速器);Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli(意大利国家核物理研究所那不勒斯分部);Gran Sasso Science Institute (GSSI)(格兰萨索科学研究所);Max-Planck-Institut für Physik(马克斯·普朗克物理学研究所)
Single-wave solutions of the neutrino fast flavor system. Part II. Weak instabilities and their resonant behavior
Deutsches Elektronen-Synchrotron DESY(德国电子同步加速器);Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli(意大利国家核物理研究所那不勒斯分部);Gran Sasso Science Institute (GSSI)(格兰萨索科学研究所);Max-Planck-Institut für Physik(马克斯·普朗克物理研究所)
Slow and fast collective neutrino oscillations: Invariants and reciprocity
Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所);Max-Planck-Institut für Physik (Werner-Heisenberg-Institut)(马克斯·普朗克物理研究所)