The Time Machine Factory [unspeakable, speakable] on Time Travel - TMF2024

Session

Session I. Chronology and causality, CTS

23 Sept 2024, 09:10

Vallauri Hall (INRiM historical building, Turin)

Conveners

Session I. Chronology and causality, CTS

• Sandro Coriasco (UNITo)

101. The Cauchy Problem in Spacetimes with Closed Timelike Curves

James Vickers (University of Southampton)

23/09/2024, 09:10

talk

In this talk we will start by reviewing the structure of some model spacetimes containing closed timelike curves (CTCs) such as Misner space, and spacetimes with moving or rotating cosmic strings. In general such spacetimes contain both a chronal and non-chronal region separated by a Cauchy horizon. We give initial data for the wave equation on a partial Cauchy surface in the chronal region...

100. Asymptotic analysis of isolated gravitational systems

Rodrigo Avalos (University of Tübingen)

23/09/2024, 09:45

talk

A central result within mathematical relativity is the well-posedness of the initial value formulation of GR for initial data satisfying Einstein constraint equations, where uniqueness of maximal globally hyperbolic developments of initial data is consistent with the type of determinism expected from classical physical theories. In this context, isolated gravitational systems are modelled by...

102. The singularity theorems of General Relativity and their low regularity extensions

Roland Steinbauer (Faculty of Mathematics, University of Vienna)

23/09/2024, 10:50

talk

We review several recent low regularity versions of the singularity theorems of General Relativity. Following a brief recap of the classical theorems of Penrose and Hawking we focus on the analytical aspects of their proofs. In particular, we discuss focusing results for causal geodesics in the case of merely locally Lipschitz spacetime metrics and present corresponding recent extensions of...

107. Practical applications of closed timelike curves

Seth Lloyd (MIT)

23/09/2024, 11:25

talk

This talk investigates the practical applications of projective closed timelike curves (PCTCs).
Because PCTCs can be realized in the laboratory via post-selected experiments, some of the more counter-intuitive effects of closed timelike curves can actually be implemented. We discuss the enhancement of measurement accuracy via PCTCs, the application of closed timelike curves to game theory,...

85. The motion of gyroscopes and spinning particles on closed timelike curves.

Brien Nolan (Dublin City University)

23/09/2024, 12:05

talk

In General Relativity, time travel is associated with the existence of closed timelike curves. Such trajectories model the history of point particles, and so in this description, the body travelling into its own past is devoid of any structure. In order to begin the process of describing time-travelling extended bodies, we consider the motion of gyroscopes and spinning particles along closed...