Unconventional geometric phase gates using two four-level rf-SQUIDs with cyclic population transfer in a cavity

Abstract

We propose a scheme for realizing two-qubit quantum phase gates via an unconventional geometric phase shift using two four-level superconducting artificial atoms with cyclic population transfer (broken symmetry) in a cavity. In this scheme, the logical gates' operation only involves the metastable states of each artificial atom. Moreover, under certain conditions, the atoms are disentangled with the cavity mode. Thus, the gate is insensitive to both the atomic spontaneous emission and the cavity decay.

Keywords:

• artificial atom
• quantum phase gate
• unconventional geometric phase

Acknowledgements

This work is supported by the National Science Foundation of China (Grant No. 10674018), the Person with Ability Study Foundation of Henan University of Science and Technology (No. 06025), the Natural Science Foundation of Hunan Province (Grant No. 06JJ5015). China Postdoctoral Science Foundation funded project (No. 20070420379).