Kappa vacua: enhancing the Unruh temperature

We provide further elaboration on kappa mode, which is a mode constructed by the linear combination of Rindler modes in the right and the left Rindler wedges, exhibiting norms with opposite signs. We establish a relation among different kappa vacua, resembling the thermofield double state. However, the energy of a kappa photon no longer exhibits a linear dependence on its frequency, unless the limit of kappa -> 0 (the Rindler vacuum) is taken into account. In other words, a kappa vacuum can be expressed in terms of the Rindler vacuum as the conventional thermofield double state, with the usual energy for a photon. However, it features a modified Unruh temperature given by T-kappa = (h) over bara/2 pi c kappa(B) kappa. Consequently, when a uniformly accelerated observer with an acceleration a is immersed in a kappa-vacuum, they perceive a thermal bath. However, the temperature experienced by the observer is a modified Unruh temperature denoted as T-kappa. Remarkably, the Unruh temperature can be enhanced by an arbitrary factor of kappa