Higher-order Lorentz-invariance violation, quantum gravity and fine-tuning

Understand

The issue of Lorentz fine-tuning in effective theories containing higher-order operators is studied.

• To this end, we focus on the Myers-Pospelov extension of QED with dimension-five operators in the photon sector and standard fermions.
• We compute the fermion self-energy at one-loop order considering its even and odd $CPT$ contributions.
• In the even sector we find small radiative corrections to the usual parameters of QED which also turn to be finite.