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A ring resonator involves a scattering process where a part of the output is fed again into the input. The same formal structure is encountered in the problem of time travel in a neighborhood of a closed timelike curve (CTC). We know how to…

Quantum Physics · Physics 2022-07-19 Marek Czachor

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

Many results have been recently obtained regarding the power of hypothetical closed time-like curves (CTCs) in quantum computation. Here we show that the one-way model of measurement-based quantum computation encompasses in a natural way…

Quantum Physics · Physics 2011-01-27 Raphael Dias da Silva , Ernesto F. Galvao , Elham Kashefi

We introduce a general categorical framework to reason about quantum theory and other process theories living in spacetimes where Closed Timelike Curves (CTCs) are available, allowing resources to travel back in time and provide…

Quantum Physics · Physics 2019-02-04 Nicola Pinzani , Stefano Gogioso , Bob Coecke

We construct a class of closed timelike curves (CTCs) using a compactified extra dimension $u$. A nonzero metric element $g_{tu}(u)$ enables particles to travel backwards in global time $t$. The compactified dimension guarantees that the…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Chiu Man Ho , Thomas J. Weiler

Inspired by some recent works of Tippett-Tsang and Mallary-Khanna-Price, we present a new spacetime model containing closed timelike curves (CTCs). This model is obtained postulating an ad hoc Lorentzian metric on $\mathbb{R}^4$, which…

General Relativity and Quantum Cosmology · Physics 2018-09-07 Davide Fermi , Livio Pizzocchero

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

We consider two approaches to evading paradoxes in quantum mechanics with closed timelike curves (CTCs). In a model similar to Politzer's, assuming pure states and using path integrals, we show that the problems of paradoxes and of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Allen Everett

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

The possible existence of closed timelike curves (CTCs) draws attention to fundamental questions about what is physically possible and what is not. An example is the "no cloning theorem" in quantum mechanics, which states that no physical…

Quantum Physics · Physics 2015-06-05 D. Ahn , C. R. Myers , T. C. Ralph , R. B. Mann

In a recent paper, Mallett found a solution of the Einstein equations in which closed timelike curves (CTC's) are present in the empty space outside an infinitely long cylinder of light moving in circular paths around an axis. Here we show…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Ken D. Olum , Allen Everett

We consider causality respecting (CR) quantum systems interacting with closed timelike curves (CTCs), within the Deutsch model. We introduce the concepts of popping up and elimination of quantum information and use them to show that…

Quantum Physics · Physics 2018-07-17 Asutosh Kumar , Indranil Chakrabarty , Arun Kumar Pati , Aditi Sen De , Ujjwal Sen

The theory of general relativity predicts the existence of closed time-like curves (CTCs), which theoretically would allow an observer to travel back in time and interact with their past self. This raises the question of whether this could…

Quantum Physics · Physics 2026-05-26 Germain Tobar , Fabio Costa

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

Quantum computation with quantum data that can traverse closed timelike curves represents a new physical model of computation. We argue that a model of quantum computation in the presence of closed timelike curves can be formulated which…

Quantum Physics · Physics 2008-11-26 Dave Bacon

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

Toy models for quantum evolution in the presence of closed timelike curves (CTCs) have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and…

Quantum Physics · Physics 2013-05-30 J. L. Pienaar , C. R. Myers , T. C. Ralph

This article describes a Turing machine which can solve for $\beta^{'}$ which is RE-complete. RE-complete problems are proven to be undecidable by Turing's accepted proof on the Entscheidungsproblem. Thus, constructing a machine which…

Computational Complexity · Computer Science 2018-04-24 Mark Inman

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

Closed time-like curves naturally appear in a variety of chronology-violating space-times. In these space-times, the Principle of Self-Consistency demands an harmony between local and global affairs that excludes grandfather-like paradoxes.…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Gustavo E. Romero , Diego F. Torres