Nambu-Goldstone bosons and the Higgs mechanism without Lorentz invariance: Analysis based on constrained-system theory

Understand

First, we develop the counting rule for Nambu-Goldstone bosons to the system including two-time derivative terms.

• In this case, the type-II Nambu-Goldstone bosons may appear along with the massive Nambu-Goldstone ones.
• The number of the bosons is not reduced in contrast to the system without two-time derivative terms.
• We also investigate the reduction of the degrees of freedom from the perspective of the Dirac-Bergmann theory of constraints and reproduce the counting rule for Nambu-Goldstone bosons without Lorentz invariance.