Spontaneous Breakdown of the Lorentz Invariance in Three-Dimensional   Gauge Theories
  In a class of renormalizable three-dimensional abelian gauge theory the Lorentz invariance is spontaneously broken by dynamical generation of a magnetic field $B$. The true ground state resembles that of the quantum Hall effect. An originally topologically massive photon becomes gapless, fulfilling the role of the Nambu-Goldstone boson associated with the spontaneous breaking of the Lorentz invariance. We give a simple explanation and a sufficient condition for the spontaneous breaking of the Lorentz invariance with the aid of the Nambu-Goldstone theorem. The decrease of the energy density by $B \not= 0$ is understood mostly due to the shift in zero-point energy of photons. For PASCOS'94. 
Yutaka Hosotani