title: Heisenberg limited Sagnac interferometry.
abstract: We show how the entangled photons produced in parametric down conversion can be used to improve the sensitivity of a Sagnac interferometer. Two-photon and four-photon coincidences increases the sensitivity by a factor of two and four respectively. Our results apply to sources with arbitrary pumping and squeezing parameters.
authors: Aziz
authors: A
authors: Kolkiran
authors: G S
authors: GS
authors: Agarwal