Coherently manipulating two-qubit quantum information using a pair of simultaneous laser pulses

¹ Frontier Research System, The Institute of Physical and Chemical Research (RIKEN) - Wako-shi, Saitama, 351-0198, Japan
² Institute of Quantum Optics and Quantum Information, Department of Physics Shanghai Jiaotong University - Shanghai 200030, PRC
³ Center for Theoretical Physics, Physics Department Center for the Study of Complex Systems, The University of Michigan Ann Arbor, MI 48109-1120, USA

Received: 6 May 2003
Accepted: 28 October 2003

Abstract

Several sequential operations are usually needed for implementing controlled quantum gates and generating entanglement between a pair of quantum bits. Based on the conditional quantum dynamics for a two-ion system beyond the Lamb-Dicke limit, here we propose a theoretical scheme for manipulating two-qubit quantum information, i.e., implementing a universal two-qubit quantum gate and generating a two-qubit entangled state, by using a pair of simultaneous laser pulses. Neither the Lamb-Dicke approximation nor the auxiliary atomic level are required. The experimental realizability of this simple approach is also discussed.