# What are the cosmic dispirations?

When I described dispirations in a little paper long ago (Phil Mag 1970 22 949-952) I had biological and polymeric materials in my mind. They have since been found in crystalline polymers and liquid crystals. But now I see cosmic dispirations in the literature. What are they? Are they singularities formed by a relative screw displacement of the surfaces of a cut? Do they depend on any underlying symmetry? What kind of magnitude is the rotational component? Are they concepts in 4D space? Are they line singularities? Can they be described for someone like me who knows almost nothing about cosmology?

## All Answers (9)

V. T. Toth· N/Ads^2 = dt^2 - dr^2 - r^2dφ^2 - dZ,

then the defect is given by identifying points with coordinates

(t,r,φ,Z) ~ (t,r,φ + 2πα, Z + 2πκ),

where α and κ are parameters that characterize the disclination and the screw dislocation, respectively.

There are no singularities involved. The spacetime is flat (Minkowski), but with non-trivial topology. The paper above actually attempts to calculate the behavior of a scalar field in the presence of such a defect.

Robert J. Low· Coventry UniversityWilliam F Harris· University of JohannesburgRobert J. Low· Coventry UniversityV. T. Toth· N/AWilliam F Harris· University of JohannesburgRobert J. Low· Coventry UniversityWilliam F Harris· University of JohannesburgRobert J. Low· Coventry UniversityCan you help by adding an answer?