Thermo field dynamics in the Lorentz-violating Myers–Pospelov model

A generalization at finite temperature of the scalar Myers–Pospelov quantum field theory with mass dimension five operators that break Lorentz symmetry is considered. In particular, we introduce a thermal vacuum and a doubled Hilbert space within the formalism of Thermo Field Dynamics (TFD) to account for extended quantum field effects. The higher-order operators in the effective Lagrangian give rise to negative-metric modes, which are treated using a perturbative method. The perturbative modes that propagate correspond to standard second-order equations of motion with Lorentz-violating modifications without altering the number of degrees of freedom. In this perturbative, Lorentz-violating TFD framework, we investigate the finite-temperature effects, including thermal fluctuations and size effects.