Misner space is an abstract mathematical spacetime,[1] first described by Charles W.
It is a simplified, two-dimensional version of the Taub–NUT spacetime.
It contains a non-curvature singularity and is an important counterexample to various hypotheses in general relativity.
Michio Kaku develops the following analogy for understanding the concept: "Misner space is an idealized space in which a room, for example, becomes the entire universe.
This suggests that the left and right wall are joined, in some sense, as in a cylinder.
Misner space is often studied because it has the same topology as a wormhole but is much simpler to handle mathematically.
If the walls move, then time travel might be possible within the Misner universe.
"[3] The simplest description of Misner space is to consider two-dimensional Minkowski space with the metric with the identification of every pair of spacetime points by a constant boost It can also be defined directly on the cylinder manifold
by the metric The two coordinates are related by the map and Misner space is a standard example for the study of causality since it contains both closed timelike curves and a compactly generated Cauchy horizon, while still being flat (since it is just Minkowski space).
This is the chronology horizon : there are no closed timelike curves in the region
, while every point admits a closed timelike curve through it in the region
This is due to the tipping of the light cones which, for
Misner space was the first spacetime where the notion of chronology protection was used for quantum fields,[4] by showing that in the semiclassical approximation, the expectation value of the stress-energy tensor for the vacuum