Quantum gyroscopes and Godel's universe:: entanglement opens a new testing ground for cosmology -: art. no. 37

Some exact solutions of Einstein's field equations represent a rotating universe. One example is Godel's cosmological model. Bianchi solutions generalize the Godel metric and include the expansion of the universe. We propose a measurement of the cosmic rotation using a light or matter wave interferometer based on the Sagnac effect. Entanglement between the quanta employed in this quantum gyroscope enhances the accuracy, thereby coming closer to the more-than-challenging requirements of such experiments.