Kappa vacua: Enhancing the Unruh temperature

We elaborate more on $\kappa$-mode, a mode that was found by a combination of Rindler modes in the right and left Rindler wedges with opposite sign norms. We find a relation between different kappa vacua, which is a generalization of the thermofield double state. However, a $\kappa$-vacuum can be written in terms of the Rindler vacuum as the thermofield double state, with a modified Unruh temperature of $T_{\kappa}=\frac{\hbar a}{2\pi c k_B}\,\kappa$. 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 $\kappa$.