Gauge Theory of Oriented Media
The concept of wave field is introduced to represent oriented media. The wave field is a tensor field of second rank, and directors are its eigenvectors. This exhibition of directors defines a natural gauge group inherit in continua and allows one to derive from variational principle general relativistic and gauge invariant equations for the wave field in question. Thus, the gauge-theoretical approach to continuum with internal degrees of freedom gives unambiguous and minimally coupled theory.
gr-qc↗