Solar constraints on new couplings between electromagnetism and gravity
Abstract
The unification of quantum field theory and general relativity is a fundamental goal of modern physics. In many cases, theoretical efforts to achieve this goal introduce auxiliary gravitational fields, ones in addition to the familiar symmetric second-rank tensor potential of general relativity, and lead to nonmetric theories because of direct couplings between these auxiliary fields and matter. Here, we consider an example of a metric-affine gauge theory of gravity in which torsion couples nonminimally to the electromagnetic field. This coupling causes a phase difference to accumulate between different polarization states of light as they propagate through the metric-affine gravitational field. Solar spectropolarimetric observations are reported and used to set strong constraints on the relevant coupling constant k: k2<(2.5 km)2.
- Publication:
-
Physical Review D
- Pub Date:
- March 2004
- DOI:
- 10.1103/PhysRevD.69.062001
- arXiv:
- arXiv:gr-qc/0402055
- Bibcode:
- 2004PhRvD..69f2001S
- Keywords:
-
- 04.80.Cc;
- 04.50.+h;
- 96.60.Tf;
- Experimental tests of gravitational theories;
- Gravity in more than four dimensions Kaluza-Klein theory unified field theories;
- alternative theories of gravity;
- Solar electromagnetic emission;
- General Relativity and Quantum Cosmology;
- Astrophysics
- E-Print:
- Accepted for publication in Phys.Rev. D