+ (t)

They are angular frequencies of two different nonnal mode solutions of the Heisenberg equations. The firstnonnal mode with angular frequency (J)_ is called the Goldstone mode or Goldstone boson which represents quantum field dynamies corresponding to a wave propagation with angular frequency (J)_. By the particle-wave duality in quantum field theory, it is nothing but a boson with energy equals to the angular frequency (J)_.