期刊：
JOURNAL OF PHYSICS-CONDENSED MATTER,2010年22(20):205501 ISSN：0953-8984
通讯作者：
Deng, Xiaohui
作者机构：
[Wang, Wenwei; Deng, Xiaohui; Zhang, Dengyu] Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421008, Peoples R China.;[Lu, Wei] Hong Kong Polytech Univ, Dept Appl Phys, Kowloon, Hong Kong, Peoples R China.;[Fan, Bingbing] City Univ Hong Kong, Dept Phys & Mat Sci, Hong Kong, Hong Kong, Peoples R China.;[Fan, Bingbing] City Univ Hong Kong, COSDAF, Hong Kong, Hong Kong, Peoples R China.;[Fan, Bingbing] Zhengzhou Univ, Sch Mat Sci & Engn, Zhengzhou, Henan, Peoples R China.
通讯机构：
[Deng, Xiaohui] H;Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421008, Peoples R China.
摘要：
The first-principles spin polarization method is used to investigate the magnetic properties of graphite boron nitride (g-BN) sheet induced by Fe doping. We find that a nitrogen or boron atom substituted by Fe can induce a magnetic moment. From standard Mulliken population analysis, we also find that the magnetic moment is mainly dominated by Fe 3d states. Using Heisenberg exchange coupling theory, we study the exchange coupling mechanisms by constructing two-Fe centers in g-BN. The results show the presence of relatively strong exchange coupling for two-Fe substituted two-B atoms and the coupling is ferromagnetic. For the case of two-Fe substituted two-N atoms, the coupling is antiferromagnetic and the exchange coupling is very weak. The paper enriches recent molecular magnetic investigations.
摘要：
Based on the full two-dimensional characteristics of the quasi-phase-matched fan-out periodically poled crystal, a scalable and engineerable scheme for ultrabroadband optical parametric chirped-pulse amplification is proposed, which can significantly broaden the gain bandwidth by the spatial separation of different frequency components of the signal pulse and manipulation of the distribution of the pump beam along the fan-out direction of the crystal. The theoretical analysis shows that the signal pulse can be amplified with minimal spectrum narrowing, and the initial spectrum can be broadened considerably if needed. Based on this scheme, using a fan-out periodically poled 5% mol MgO-doped congruent lithium niobate with a configuration of 5×0.5×5 mm3 and two pump beams, the 3.3−μm middle-infrared ultrabroadband optical parametric chirped-pulse amplifier is designed. The numerical computation results confirm that the −3 dB gain bandwidth of this amplifier exceeds 320 nm and can be further broadened.
摘要：
In this paper, precise synchronization of the femtosecond and picosecond laser regenerative amplifiers with different wavelengths and independent seed oscillators was achieved using the electronic phase-locked loop and global clock techniques. The root-mean-square relative timing jitter of the two regenerative amplifiers was measured as 0.66 ps using a modified statistical method based on the error propagation relation between the independent variables and the conventional optical cross-correlation technique. The results suggest that this method is more accurate and requires simple optical setups for low-pulse repetition rate lasers.
期刊：
International Journal of Quantum Information,2010年8(8):1301-1314 ISSN：0219-7499
通讯作者：
Wang, Xin-Wen
作者机构：
[Zhang, Deng-Yu; Gao, Feng; Wang, Xin-Wen; Tang, Shi-Qing] Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421008, Peoples R China.;[Wang, Xin-Wen] Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China.
通讯机构：
[Wang, Xin-Wen] H;Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421008, Peoples R China.
关键词：
Quantum secret sharing;GHZ states;security
摘要：
We study the security of multiparty quantum secret sharing (QSS) with multiqubit Greenberger-Horne-Zeilinger states. We give a detailed proof that the original scheme of Xiao et al. [Phys. Rev. A 69 (2004) 052307] is insecure against the interior attack (i.e. the participants' attack) which is the most serious threat for QSS protocols. Thereafter, an improvement of this QSS protocol is proposed.
作者机构：
[Wang Xin-Wen] Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421008, Peoples R China.;[Su Yu-Huan; Yang Guo-Jian; Wang Xin-Wen] Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China.
通讯机构：
[Wang Xin-Wen] H;Hengyang Normal Univ, Dept Phys & Elect Informat Sci, Hengyang 421008, Peoples R China.
关键词：
克隆;远程;协变;经济;非最大纠缠态;幺正变换;非对称;保真度
摘要：
We present explicit unitary transformations for realizing both symmetric and asymmetric one-to-many economical phase-covariant clonings of qudits. We also propose a corresponding telecloning scheme. It is shown that the fidelity of the telecloning with nonmaximally entangled states can be larger than that of the corresponding cloning. This implies that partially entangled states can be better than the maximally entangled states for our economical phase-covariant telecloning scheme.
