Results 81 to 90 of about 222 (175)

One thousand and one bubbles

Journal of High Energy Physics, 2018
We propose a novel strategy that permits the construction of completely general five-dimensional microstate geometries on a Gibbons-Hawking space. Our scheme is based on two steps.
Jesús Ávila, Pedro F. Ramírez, Alejandro Ruipérez   +2 more
doaj   +1 more source

Characterization of the null energy condition via displacement convexity of entropy

Journal of the London Mathematical Society, Volume 109, Issue 1, January 2024.
Abstract We characterize the null energy condition for an (n+1)$(n+1)$‐dimensional, time‐oriented Lorentzian manifold in terms of convexity of the relative (n−1)$(n-1)$‐Renyi entropy along displacement interpolations on null hypersurfaces. More generally, we also consider Lorentzian manifolds with a smooth weight function and introduce the Bakry–Emery ...
Christian Ketterer
wiley   +1 more source

Particle detectors under chronological hazard

Journal of High Energy Physics
We analyze how the presence of closed timelike curves (CTCs) characterizing a time machine can be discerned by placing a local particle detector in a region of spacetime which is causally disconnected from the CTCs.
Ana Alonso-Serrano, Erickson Tjoa, Luis J. Garay, Eduardo Martín-Martínez   +3 more
doaj   +1 more source

Charged Particles Moving around a Spherically Symmetric Dilatonic Black Hole

Advances in High Energy Physics, Volume 2024, Issue 1, 2024.
For the static spherically symmetric dilatonic black hole described by the Gibbons–Maeda–Garfinkle–Horowitz–Strominger geometry, we analyze the timelike trajectories for electrically charged test particles. Both cases of an electric black hole and a magnetic one are considered.
Vitalie Lungu, Marina–Aura Dariescu, Ciprian Dariescu, Cristian Stelea, Muhammad Farasat Shamir   +4 more
wiley   +1 more source

Revisiting chronology protection conjecture in the Dyonic Kerr–Sen black hole spacetime

European Physical Journal C: Particles and Fields
The chronology protection conjecture (CPC) was first introduced by Hawking after his semi-classical investigation of the behaviour of a spacetime with closed timelike curves (CTCs) in response to scalar perturbations.
Teephatai Bunyaratavej, Piyabut Burikham, David Senjaya   +2 more
doaj   +1 more source

Homogeneous Gödel-type solutions in hybrid metric-Palatini gravity

European Physical Journal C: Particles and Fields, 2018
The hybrid metric-Palatini $$f({\mathscr {R}})$$ f(R) gravity is a recently devised approach to modified gravity in which it is added to the metric Ricci scalar R, in the Einstein–Hilbert Lagrangian, a function $$f({\mathscr {R}})$$ f(R) of Palatini ...
J. Santos, M. J. Rebouças, A. F. F. Teixeira   +2 more
doaj   +1 more source

An extendible spacetime without closed timelike curves whose every extension contains closed timelike curves

14 pages, 7 ...
Andréka, H., Madarász, J., Manchak, J., Németi, I., Székely, G.   +4 more
openaire   +2 more sources

Chronology protection of rotating black holes in a viable Lorentz-violating gravity

Physics Letters B
We study causal properties of the recently found rotating black-hole solution in the low-energy sector of Hořava gravity as a viable Lorentz-violating (LV) gravity in four dimensions with the LV Maxwell field and a cosmological constant Λ(>−3/a2) for an ...
Mu-In Park, Hideki Maeda
doaj   +1 more source

Computability Theory of Closed Timelike Curves

, 2016
We ask, and answer, the question of what's computable by Turing machines equipped with time travel into the past: that is, closed timelike curves or CTCs (with no bound on their size). We focus on a model for CTCs due to Deutsch, which imposes a probabilistic consistency condition to avoid grandfather paradoxes.
Aaronson, Scott, Bavarian, Mohammad, Gueltrini, Giulio   +2 more
openaire   +3 more sources

The Singularity Theorems of General Relativity and Their Low Regularity Extensions. [PDF]

Jahresber Dtsch Math Ver, 2023
Steinbauer R.
europepmc   +1 more source