An exact solution of evolution of the field entropy in a system of three-level cascade type atom interacting with single-mode coherent field

Abstract

摘要 本文利用全量子理论，在非旋波近似下对单模相干态光场与级联型三能级原子相互作用过程中场熵随时间的演化进行了精确求解.数值计算的结果表明：随着初始时刻平均光子数n以及光场与原子的耦合强度u, v的增大，场熵的平均值先增大后减小,因此纠缠度也同样先增大后减小；随着失谐量Δ的增大，场熵的平均值逐渐减小，因此纠缠度也逐渐减小. 关键词: 相干态正交化展开 / 非旋波近似 / 场熵 Abstract In this paper,the evolution of field entropy in the system of single-mode coherent light field interacting with a three-level cascade type atom is calculated exactly in the frame of complete quantum theory and without rotating wave approximation.The numerical results indicate that with the increases of the initial mean photon number n and the atom-field coupling strengths u and v the mean value of the field entropy increases at first and then decreases.Therefore,the degrees of entanglement also increase at first and then decrease.The mean value of the entropy of the field decreases with the enlarging of the detuning Δ, which leads to the decrease of the degrees of entanglement. Keywords: coherent-state orthogonalization expansion / without rotating wave approximation / field entropy 作者及机构信息 丛红璐, 任学藻, 姜道来, 廖旭 1. 西南科技大学理学院,绵阳 621010 基金项目: 四川省自然科学基金(批准号: 2006C028)资助的课题. Authors and contacts Cong Hong-Lu, Ren Xue-Zao, Jiang Dao-Lai, Liao Xu 1. 西南科技大学理学院,绵阳 621010 参考文献 [1] ［1］Phoenix S J D, Knight P L 1988 Ann. Phys. 186 381 [2] ［2］ Phoenix S J D, Knight P L 1991 Phys. Rev. A 44 6023 [3] ［3］Obada A S F, Ahmed M M A, Faramawy F K, Khalil E M 2004 Chin. J. Phys. 42 80 [4] ［4］Faisal A A E, Wahiddin M R B, Obada A S F 2008 Opt. Commun. 281 2854 [5] ［5］Liu S M 2003 Chin. J. Quantum. Electron. 20 725 (in Chinese) ［刘素梅 2003 量子电子学报 20 725］ [6] ［6］Zou Y, Li Y P 2009 Chin. Phys. B 18 2794 [7] ［7］Zhang J F, Tan L, Liu L W, Ding C Y 2008 Acta Phys. Sin. 57 2205 (in Chinese) ［张金芳、谭磊、刘利伟、丁彩英 2008 物理学报 57 2205］ [8] ［8］Hu X P, Guo H 2009 Acta Phys. Sin. 58 272 (in Chinese) ［胡孝平、郭红 2009 物理学报 58 272］ [9] ［9］Liu T, Feng M，Wang K L 2007 Commun. Theor. Phys. 47 561 [10] ］Zhang Z J, Wang K L，Qin G 2005 Chin. Phys. 14 1317 [11] ］T Liu, K L Wang, M Feng 2007 J. Phys. B:At. Mol. Opt.2 Phys. 40 1967 [12] ］Fan Y X, Liu T, Feng M, Wang K L 2007 Commun. Theor. Phys. 47 781 [13] ］Liu T, Fan Y X, Huang S W, Wang K L, Wang Y 2007 Commun. Theor. Phys. 47 791 [14] ］Ren X Z, Jiang D L, Cong H L, Liao X 2009 Acta Phys. Sin. 58 5394 (in Chinese) ［任学藻、姜道来、丛红璐、廖旭 2009 物理学报 58 5394］ [15] ］Ren X Z, Liao X, Huang S W, Wang K L 2009 Acta Phys. Sin. 58 2680 (in Chinese) ［任学藻、廖旭、黄书文、汪克林 2009 物理学报 58 2680］ [16] ］Ren X Z, Liao X, Liu T, Wang K L 2006 Acta Phys. Sin. 55 2865 (in Chinese) ［任学藻、廖旭、刘涛、汪克林 2006 物理学报 55 2865］ [17] ］Chen Q H，Zhang Y Y, Liu T, Wang K L 2008 Phys. Rev. A 78 1050 施引文献