In a recent note' it was shown that the Goldstone theorem, ' that Lorentz-covaria. nt field theories in which spontaneous breakdown of symmetry under an internal Lie group occurs contain zero-mass… Expand

We examine a simple relativistic theory of two scalar fields, first discussed by Goldstone, in which as a result of spontaneous breakdown of U(1) symmetry one of the scalar bosons is massless, in… Expand

The two potentials for which a particle moving non-relativistically in a spherical space under the action of conservative central force executes closed orbits are found. When the curvature is zero… Expand

The infra-red and Raman selection rules for an infinite long-chain molecule having helical symmetry are discussed, and the normal modes of vibration are classified by the use of group theory. A… Expand

The F and G matrix form of the secular equation for molecular vibrations may be split into two approximate equations, of which one has as its roots the high frequencies (corresponding to relatively… Expand

SummaryTwo out of the three sets of field equations associated with Lagrangians quadratic in the Riemann-Christoffel tensor, which were recently discussed by Stephenson, are shown to be equivalent to… Expand