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Many solutions of Einstein's field equations contain closed timelike curves (CTC). Some of these solutions refer to ordinary materials in situations which might occur in the laboratory, or in astrophysics. It is argued that, in default of a…

General Relativity and Quantum Cosmology · Physics 2009-11-07 W. B. Bonnor

The conceptual definition and understanding of time, both quantitatively and qualitatively is of the utmost difficulty and importance. As time is incorporated into the proper structure of the fabric of spacetime, it is interesting to note…

General Relativity and Quantum Cosmology · Physics 2013-10-21 Francisco S. N. Lobo

We investigate vacuum solutions of Einstein's equation for a universe with an S^1 topology of time. Such a universe behaves like a time-machine and has geodesics which coincide with closed time-like curves (CTCs). A system evolving along a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Moninder Singh Modgil , Deshdeep Sahdev

Notoriously, the Einstein equations of general relativity have solutions in which closed timelike curves (CTCs) occur. On these curves time loops back onto itself, which has exotic consequences. However, in order to make time travel stories…

General Relativity and Quantum Cosmology · Physics 2021-05-26 Ruward A. Mulder , Dennis Dieks

We present a cyclic symmetric space-time, admitting closed time-like curves (CTCs) which appear after a certain instant of time, i. e., a time-machine space-time. These closed time-like curves evolve from an initial spacelike hypersurface…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Faizuddin Ahmed

Closed timelike curves (CTCs) appear in many solutions of the Einstein equation, even with reasonable matter sources. These solutions appear to violate causality and so are considered problematic. Since CTCs reflect the global properties of…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Sergei Slobodov

One out of many emerging implications from solutions of Einstein's general relativity equations are closed timelike curves (CTCs), which are trajectories through spacetime that allow for time travel to the past without exceeding the speed…

General Relativity and Quantum Cosmology · Physics 2019-02-13 Małgorzata Bartkiewicz , Andrzej Grudka , Ryszard Horodecki , Justyna Łodyga , Jacek Wychowaniec

The existence of time machines, understood as spacetime constructions exhibiting physically realised closed timelike curves (CTCs), would raise fundamental problems with causality and challenge our current understanding of classical and…

General Relativity and Quantum Cosmology · Physics 2009-11-07 G. M. Shore

While closed timelike curves (CTCs) are not known to exist, studying their consequences has led to nontrivial insights in general relativity, quantum information, and other areas. In this paper we show that if CTCs existed, then quantum…

Quantum Physics · Physics 2009-11-13 Scott Aaronson , John Watrous

Closed timelike curves (CTCs) are trajectories in spacetime that effectively travel backwards in time: a test particle following a CTC can in principle interact with its former self in the past. CTCs appear in many solutions of Einstein's…

Mallett has exhibited a cylindrically symmetric spacetime containing closed timelike curves produced by a light beam circulating around a line singularity. I analyze the static version of this spacetime obtained by setting the intensity of…

General Relativity and Quantum Cosmology · Physics 2011-02-28 Ken D. Olum

We study the paradoxical aspects of closed time-like curves and their impact on the theory of computation. After introducing the $\text{TM}_\text{CTC}$, a classical Turing machine benefiting CTCs for backward time travel, Aaronson et al.…

Computational Complexity · Computer Science 2023-01-30 Sara Babaee Khanehsar , Farzad Didehvar

While it is tempting to think of closed timelike curves (CTCs) around rotating bodies such as a black hole as being "caused" by the rotation of the source, Andr\'eka et al. pointed out that the underlying physics is not as straightforward…

General Relativity and Quantum Cosmology · Physics 2022-02-01 Yuanyuan Duan , Fangxun Liu , Yu Wang , Yen Chin Ong

We extend the argument that spacetimes generated by two timelike particles in D=3 gravity (or equivalently by parallel-moving cosmic strings in D=4) permit closed timelike curves (CTC) only at the price of Misner identifications that…

General Relativity and Quantum Cosmology · Physics 2009-11-19 S. Deser , Alan R. Steif

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. Our study shows that not…

Quantum Physics · Physics 2024-07-19 Ana Alonso-Serrano , Erickson Tjoa , Luis J. Garay , Eduardo Martín-Martínez

We consider the region of closed timelike curves (CTC's) in three-dimensional flat Lorentz spacetimes. The interest in this global geometrical feature goes beyond the purely mathematical. Such spacetimes may be considered lower-dimensional…

Differential Geometry · Mathematics 2009-11-07 Virginie Charette , Todd A. Drumm , Dieter Brill

General relativity predicts the existence of closed timelike curves (CTCs), along which an object could travel to its own past. A consequence of CTCs is the failure of determinism, even for classical systems: one initial condition can…

Quantum Physics · Physics 2021-05-20 Lachlan G. Bishop , Fabio Costa , Timothy C. Ralph

In this paper, we investigate the possibility of using closed timelike curves (CTCs) in relativistic hypercomputation. We introduce a wormhole based hypercomputation scenario which is free from the common worries, such as the blueshift…

General Relativity and Quantum Cosmology · Physics 2012-11-27 Hajnal Andréka , István Németi , Gergely Székely

The discovery by Gott of a remarkably simple spacetime with closed timelike curves (CTC's) provides a tool for investigating how the creation of time machines is prevented in classical general relativity. The Gott spacetime contains two…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Sean M. Carroll , Edward Farhi , Alan H. Guth , Ken D. Olum

We consider gravity in 2+1 dimensions in presence of extended stationary sources with rotational symmetry. We prove by direct use of Einstein's equations that if i) the energy momentum tensor satisfies the weak energy condition, ii) the…

High Energy Physics - Theory · Physics 2009-10-22 P. Menotti , D. Seminara
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