We first investigate the nonlinear optical response of a five-level tripod atomic system in electromagnetically induced transparency and then propose a 3-qubit phase gate protocol based on the fifth-order nonlinearity. The cross-phase modulation among the three weak fields induced by the fifth-order nonlinearity in electromagnetically induced transparency can produce the phase shift of order π, which can be used to realize the 3-qubit polarization phase gate. This protocol should have potential applications in quantum information processing.
© 2008 Optical Society of America
Original Manuscript: October 23, 2007
Revised Manuscript: December 12, 2007
Manuscript Accepted: January 18, 2008
Published: March 20, 2008
Pengbo Li, Ying Gu, Lijun Wang, and Qihuang Gong, "Fifth-order nonlinearity and 3-qubit phase gate in a five-level tripod atomic system," J. Opt. Soc. Am. B 25, 504-512 (2008)