We consider how to formulate semiclassical problems in the context of the AdS/CFT correspondence, based on the proposal of Compere and Marolf [arXiv:0805.1902]. Our prescription involves the effective action with self-action term for boundary dynamical fields, which can be viewed as imposing mixed boundary conditions for the gravity dual. We derive the semiclassical Einstein equations sourced...

"Facets of Unitarity Violation in Dynamical Spacetimes" by Ka Hei Choi (Ludwig Maximilian University of Munich);

"Gravity and the Superposition Principle" by Hristu Culetu (Ovidius University);

"The master Dyson-Schwinger equation and the Wilsonian renormalization group flows in a generally covariant setting" by Andras Laszlo (Wigner Research Centre for Physics, Budapest);

"Uniformly...

Black hole spacetimes harbor intricate internal structures, featuring geometry that extends through an inner horizon to another external universe. This regularity of the inner horizon, which plays the causal role of a Cauchy horizon, challenges predictability within black holes. The strong cosmic censorship conjecture offers a solution, asserting that the Cauchy horizon becomes sufficiently...

We consider the global Hadamard condition and the notion of Hadamard parametrix whose use is pervasive in algebraic QFT in curved spacetime (see references in the main text). We point out the existence of a technical problem in the literature concerning well-definedness of the global Hadamard parametrix in normal neighbourhoods of Cauchy surfaces. We discuss in particular the definition of the...

We confirm that Hawking radiation from an analogue black hole in a Bose-Einstein condensate is spontaneous, thermal, and stationary. Furthermore, we follow the time evolution of the Hawking radiation, and compare and contrast it with the predictions for real black holes. We observe the ramp up of the Hawking radiation, similar to a real black hole. The end of the spontaneous Hawking radiation...

We investigate the roots of unitarity violations of quantum field theory in dynamical spacetimes

and its connection to back-reactions and measurement processes. Within the framework of effective

field theories, local observables require compact configuration spaces given by the domain

of validity of the effective description and in accordance with detector specifications. Using the...