upward

Fields

Alamoudi S M, Boyanovsky D, Takakura F I, Domain walls out of equilibrium, PRD 58, 105003 (1998)

Dashen R F, Hasslacher B, Neveu A, Particle spectrum in model field theories from semiclassical functional integral techniques, PRD 11, 3424 (1975)

Goldstone J, Jackiw R, Quantization of nonlinear waves, PRD 11, 1486 (1975)