Hawking radiation and regularity of quantum states in two-dimensional black holes spacetimes

This Master's Thesis aims to investigate the regularity properties of quantum vacuum states across the horizon in various spacetime geometries. One of the most captivating phenomena in theoretical physics is the Hawking effect, the emission of thermal radiation by a black hole. A straightforward approach to derive this phenomenon involves examining the interplay between distinct quantum states defined in a curved spacetime. To ensure an accurate description of the field, the quantum state should exhibit regularity throughout the entire spacetime. A valuable method for studying state behavior involves analyzing the expectation value of the energy-momentum tensor. Following a detailed exposition of this analytical procedure within the familiar Schwarzschild spacetime, attention turns to the Reissner-Nordström spacetime, where the construction of a regular quantum state is found to be not possible. Concluding the investigation, we introduce the concept of regular black holes, characterized by spacetimes without physical singularities while still retaining essential black hole attributes. Our analysis centers on the Simpson-Visser spacetime, where the construction of a vacuum state exhibiting regularity across the entire spacetime is achievable.