Unruh Effect in nonlocal field theories

We study the Unruh Effect for a wide class of nonlocal theories. Using the approach of Bogoliubov coefficients, we show that the Unruh Effect remains entirely unmodified in these theories. However, for those nonlocal theories which incorporate a minimal length, the approach using Unruh-DeWitt detectors predicts a modification in the Unruh Effect. Previous work shows that this modification may even be drastic. This appears contradictory with two apparently equivalent methods giving different results. We investigate the origin of the contradiction and show that for these theories, the two methods are indeed inequivalent. We argue that the detector method incorporates an assumption of local interaction that does not hold for nonlocal theories, and, therefore, the method of Bogoliubov coefficients is preferable.