Preparation of Multi-Atom Entangled States with a Single Cavity in a Thermal State**The project supported by Fok Ying Tung Education Foundation, National Natural Science Foundation of China under Grant No. 60 008 003, Fujian Provincial Natural Science Foundation of China under Grant Nos. K20 004 and F0 110 027, and Funds from Fuzhou University

Abstract

A scheme is suggested for the generation of multi-atom maximally entangled states with a cavity in a thermal state. In this scheme several appropriately prepared two-level atoms are simultaneously sent through the nonresonant cavity. We divide the whole atom-cavity interaction time into two equal parts. At the end of the first part a π pulse is applied to the atoms using a classical field. Then the photon-number-dependent shifts on the atomic states are cancelled and the atomic system finally evolves to a maximally entangled state.