Do existing EFE solutions support Closed Timelike Curves?

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Discussion Overview

The discussion revolves around the existence of solutions to the Einstein Field Equations (EFE) that support Closed Timelike Curves (CTCs). Participants explore various spacetime geometries and their implications for the possibility of CTCs, including theoretical models and their physical plausibility.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants propose that there are EFE solutions, such as Gödel spacetime, that admit CTCs.
  • Others mention that many EFE solutions violate energy conditions, including the interior of a Kerr black hole and the Tipler cylinder, as potential examples supporting CTCs.
  • A participant questions whether Gödel's spacetime allows for CTCs without regions of infinite curvature or black holes.
  • Another participant clarifies that Gödel's original solution does not contain black holes, but other Kerr-Gödel-type solutions may include them.
  • There is a query about the plausibility of Gödel or Kerr-Gödel-type solutions as models for our Universe.
  • One participant expresses a strong skepticism regarding the acceptance of CTCs in standard physics, suggesting that they are not considered plausible by most physicists.
  • A later reply asserts that, according to current standard physics, there is no way to achieve a CTC journey or reach distant regions of spacetime via a wormhole.

Areas of Agreement / Disagreement

Participants express differing views on the plausibility of CTCs in the context of current physics, with some supporting the existence of theoretical models and others rejecting their feasibility in the real Universe.

Contextual Notes

Discussion includes references to specific solutions and their properties, but does not resolve the implications of energy conditions or the physical reality of CTCs.

cianfa72
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TL;DR
About the existence of EFE solutions supporting Closed Timelike Curves
Hi, I'm curious about the following: taking the point of view of the standard physics of spacetime including EFE's solutions, are there solutions that admit Closed Timelike Curves (CTC) ?

In other words: do exist global topologies and Lorentzian metrics solutions of the EFE that support CTCs ?

Thanks.
 
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cianfa72 said:
TL;DR: About the existence of EFE solutions supporting Closed Timelike Curves

Hi, I'm curious about the following: taking the point of view of the standard physics of spacetime including EFE's solutions, are there solutions that admit Closed Timelike Curves (CTC) ?

In other words: do exist global topologies and Lorentzian metrics solutions of the EFE that support CTCs ?

Thanks.
Yes, of course. For example the Gödel spacetime.
 
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cianfa72 said:
TL;DR: About the existence of EFE solutions supporting Closed Timelike Curves

Hi, I'm curious about the following: taking the point of view of the standard physics of spacetime including EFE's solutions, are there solutions that admit Closed Timelike Curves (CTC) ?

In other words: do exist global topologies and Lorentzian metrics solutions of the EFE that support CTCs ?

Thanks.
There are many EFE solutions that violate some, several, or all of the energy conditions. In addition to Gödel's universe, the interior of a Kerr black hole or the Tipler cylinder.
 
javisot said:
There are many EFE solutions that violate some, several, or all of the energy conditions. In addition to Gödel's universe, the interior of a Kerr black hole or the Tipler cylinder.
Well, then, for instance in Gödel's universe, by following a suitable timelike path, one could came back to the event where the journey began.

Does the geometry/topology of Gödel's spacetime allow CTCs without having regions of infinite curvature or something like that (e.g. black holes) ?
 
cianfa72 said:
Well, then, for instance in Gödel's universe, by following a suitable timelike path, one could came back to the event where the journey began.

Does the geometry/topology of Gödel's spacetime allow CTCs without having regions of infinite curvature or something like that (e.g. black holes) ?
Gödel's original solution does not contain black holes. Other Kerr-Gödel-type solutions may include them, for example, https://arxiv.org/abs/1207.1984
 
javisot said:
Gödel's original solution does not contain black holes. Other Kerr-Gödel-type solutions may include them, for example, https://arxiv.org/abs/1207.1984
Do physicists think that Gödel or Kerr-Gödel-type solutions could be plausible models for our Universe ?
 
cianfa72 said:
Do physicists think that Gödel or Kerr-Gödel-type solutions could be plausible models for our Universe ?
No.

(Maybe some crazy physicist, but usually not)
 
Ok, therefore, according the today standard physics, there is no way to take a CTC journey or reach some (remote) region of spacetime via a whormhole or something like that..
 
Last edited:

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