What's happening if the spacetime is torqued?

[Linker]

Einstein's GR is a theory without torsion. A gravitational theory with torsion is the Einstein-Cartan-theory. This theory predicts that a particle with spin causing torqued spacetime, but only on microscopic scales.

What would happen if the spacetime is torqued on macroscopic scales? Is it possible to induce torsion of spacetime on macroscopic scales? If yes, how it can be realized?

[MigL]

Kerr metric ?

[juanrga]

Einstein's GR is a theory without torsion. A gravitational theory with torsion is the Einstein-Cartan-theory. This theory predicts that a particle with spin causing torqued spacetime, but only on microscopic scales.

What would happen if the spacetime is torqued on macroscopic scales? Is it possible to induce torsion of spacetime on macroscopic scales? If yes, how it can be realized?

 

Both GR and Einstein-Cartan theory use stress-energy-momentum tensors, which only describe matter macroscopically. Einstein-Cartan theory considers classical spin (rotation), not the quantum spin of particles.

 

There is nothing special about torqued spacetimes. In fact, teleparallel gravity is a geometric formulation alternative to GR, where gravitational effects are described by torsion instead of curvature.

 

Einstein-Cartan is a controversial subject. In my opinion (take this with a grain of salt) it is unneeded because general relativity can deal with spin as well (spin-orbit coupling has been tested in general relativity).

Edited November 1, 2012 by juanrga