A new gauge-theoretic approach to gravity is applied to the study of rotating cylindrically-symmetric strings. The interior and exterior equations are reduced to a simple set of first-order differential equations, and suitable matching conditions are obtained. The gauge theory formulation affords a clear understanding of the physical observables in the theory, and provides simple conditions for the properties of the fields on the string axis. In this context some errors in previously published work are exposed. Three situations are discussed: the vacuum region; pressure-free matter; and a (2+1)-dimensional `ideal fluid’. In each case a set of analytic solutions is presented. It is shown that if the fluid is rotating rigidly then closed time-like curves are inevitable, despite the fact that the matter satisfies the weak energy condition.
C. J. L. Doran, A. N. Lasenby and S. F. Gull, The physics of rotating cylindrical strings, Phys. Rev. D 54(10), 6021-6031 (1996)