1969/12/25 by G. Velo, Giorgio Velo, Daniel Zwanzinger · 7 citations
Physics and Astronomy · #Quantum and Classical Electrodynamics #Quantum Mechanics and Applications #Quantum chaos and dynamical systems
paper · doi:10.1103/physrev.188.2218
We analyze critically what happens when various interaction terms are added to a Lagrangian describing a free particle with spin \ensuremath≥1. Good behavior results when the charged spin-one particle is coupled minimally to an external electromagnetic field or via a magnetic dipole moment. However, with an arbitrary electric quadrupole moment, the spin-one particle propagates noncausally (v>c) in an electrostatic field. Noncausal behavior is also found for the neutral vector field with self-coupling \ensuremathλ(W_\ensuremathμW^\ensuremathμ)2. Another kind of disease appears when the spin-two particle is given a charge: A constraint is converted into an equation of motion, so that there are six degrees of freedom instead of the desired five.