Frame dependence of the nonrelativistic limit of quantum fields

We study the nonrelativistic limit of quantum fields for an inertial and a noninertial observer. show that particle states appear as superposition relativistic particles in different frames. Hence, is frame dependent. detail this result when observer has uniform constant acceleration. Only low accelerations, accelerated agrees with about nature locally. In such quasi-inertial regime, both observers agree number describing field states. The same does not occur acceleration arbitrarily large (e.g., Unruh effect). furthermore prove wave functions are identical up to coordinate transformation relating two