In Einstein's general theory of relativity, both matter and energy can create a gravitational field. This means that the energy of a light beam can produce a gravitational field. My current research considers both the weak and strong gravitational fields produced by a single continuously circulating unidirectional beam of light. In the weak gravitational field of a unidirectional ring laser, it is predicted that a spinning neutral particle, when placed in the ring, is dragged around by the resulting gravitational field. [R. L. Mallett, "Weak gravitational field of the electromagnetic radiation in a ring laser", Phys. Lett. A 269, 214 (2000)]. [pdf]

Using the linearized Einstein gravitational field equations and the Maxwell field equations it is shown that the plane of polarization of an electromagnetic wave is rotated by the gravitational field created by the electromagnetic radiation of a ring laser. An experimental arrangement is suggested for the observation of this gravitational Faraday effect induced by the ring laser. [ D. E. Cox, J. G. O'Brien, R. L. Mallett, and C. Roychoudhuri, "Gravitational Faraday effect produced by a ring laser", Found. Phys. 37, 723 (2007)]. [pdf]

For the strong gravitational field of a circulating cylinder of light, I have found new exact solutions of the Einstein field equations for the exterior and interior gravitational fields of the light cylinder. The exterior gravitational field is shown to contain closed timelike lines.

The presence of closed timelike lines indicates the possibility of time travel into the past. This creates the foundation for a time machine based on a circulating cylinder of light. [R. L. Mallett, "The gravitational field of a circulating light beam", Foundations of Physics 33, 1307 (2003)]. [pdf]

In collaboration with Mark P. Silverman of the Department of Physics of Trinity College, a general relativistically covariant theory of a self coupled scalar field has been developed as a possible solution of the missing mass problem. We have shown that spontaneous symmetry breaking of a neutral scalar field coupled to gravity leads directly to ultra-low mass bosons, with a critical temperature far above the temperature of the universe, for most of its duration. The particles are therefore expected to condense into a degenerate Bose Einstein gas, providing a potential candidate for nonbaryonic nonluminous matter [M.P. Silverman and R.L. Mallett, "Cosmic degenerate matter: a possible solution to the problem of missing mass," Class. Quantum Grav. 18, L37 (2001); M. P. Silverman and R. L. Mallett, "Dark matter as a cosmic Bose-Einstein condensate and possible superfluid", Gen. Rel. Grav. 34, 633 (2002)].

Ronald Mallett on a visit to the
Einstein House in Bern, Switzerland