Alternative non-Gaussianity measures for quantum states based on quantum fidelity

We propose three alternative measures for non-Gaussianity of quantum states: sine distance, Bures angle, and Bures distance, which are based on quantum fidelity introduced by Wang [Phys. Lett. A 373 58 (2008)]. Using them, we evaluate the non-Gaussianity of some relevant single-mode and two-mode non-Gaussian states and find a good consistency of the three examined measures. In addition, we show that such metrics can exactly quantify the degree of Gaussianity of even Schrödinger-cat-like states of small amplitudes that can not be measured by other known non-Gaussianity measures such as the Hilbert—Schmidt metric and the relative entropy metric. We make a comparative study between all existing non-Gaussianity measures according to the metric axioms and point out that the sine distance is the best candidate among them.     

压缩真空态与压缩单光子态的相干叠加态的非经典性质

通过对量子比特态进行压缩操作,获得压缩真空态与压缩单光子态按一定的权重比例叠加而成的相干叠加态,此相干叠加态与压缩参数和权重因子有关,研究其非经典性和非高斯性.研究结果表明,通过压缩使得量子比特态的光子数分布范围变宽了.特别是从亚泊松分布和Wigner函数负定性情况分析了该量子态的非经典属性,从Wigner函数的边缘分布角度观察了该量子态的非高斯性.发现调节权重因子和压缩参数可以改善该态的非经典性和非高斯性.     

n型金属氧化物半导体场效应晶体管噪声非高斯性研究

基于n型金属氧化物半导体场效应晶体管（nMOSFET）噪声的数涨落模型,采用高阶统计量双相干系数平方和研究了nMOSFET噪声的非高斯性.通过对nMOSFET实际测试噪声的分析,发现nMOSFET器件噪声存在非高斯性;小尺寸器件噪声的非高斯性强于大尺寸器件;在器件的强反型线性区,其非高斯性随着漏压的增加而增加.文中还通过蒙特卡罗模拟和中心极限定理理论对nMOSFET噪声的非高斯性作了深入的探讨. 关键词： 噪声 非高斯性 n型金属氧化物半导体场效应晶体管 氧化层陷阱     

Non-Gaussianity of Racetrack Inflation Models

In this paper, we use the result in [C.Y. Sun and D.H. Zhang, arXiv:astro-ph/0510709] to calculate the non-Gaussianity of the racetrack models in [J.J. Blanco-Pillado, et al., JHEP 0411 (2004) 063; arXiv:hep-th/0406230] and [J.J. Blanco-Pillado, et al., arXiv:hep-th/0603129]. The two models give different non-Gaussianities. Both of them are reasonable. However, we find that, for multi-field inflationary models with the non-trivial metric of the field space, the condition of the slow-roll cannot guarantee small non-Gaussianities.