Torsional monopoles and torqued geometries in gravity and condensed matter

Phys Rev Lett. 2011 Apr 22;106(16):161102. doi: 10.1103/PhysRevLett.106.161102. Epub 2011 Apr 22.

Abstract

Torsional degrees of freedom play an important role in modern gravity theories as well as in condensed matter systems where they can be modeled by defects in solids. Here we isolate a class of torsion models that support torsion configurations with a localized, conserved charge that adopts integer values. The charge is topological in nature, and the torsional configurations can be thought of as torsional "monopole" solutions. We explore some of the properties of these configurations in gravity models with a nonvanishing curvature and discuss the possible existence of such monopoles in condensed matter systems. To conclude, we show how the monopoles can be thought of as a natural generalization of the Cartan spiral staircase.