Stability, causality, and Lorentz and CPT violation

  title={Stability, causality, and Lorentz and CPT violation},
  author={A. Kosteleck{\'y} and R. Lehnert},
  journal={Physical Review D},
Stability and causality are investigated for quantum field theories incorporating Lorentz and CPT violation. Explicit calculations in the quadratic sector of a general renormalizable lagrangian for a massive fermion reveal that no difficulty arises for low energies if the parameters controlling the breaking are small, but for high energies either energy positivity or microcausality is violated in some observer frame. However, this can be avoided if the lagrangian is the sub-Planck limit of a… Expand
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Note that it is common to find field theories in which consistency allows only a particular range for a parameter in the Lagrangian. For example
    might appear inappropriate. However, the effect of a nonzero trace in c is merely to scale the normalization of the Dirac field ͓5͔. For example
    • ͓37͔ The coefficients c in the Lagrangian ͑1͒ are defined to be traceless
    ͑1988͒; Nucl. Phys. B336, 263 ͑1990͒
    • Phys. Rev. Lett