Extension of the Quantum Mechanical Principle of Superposition to Non-Identical States with Short Life Times

We apply the principle of superposition to two quantum mechanical states of which one has a short life time 1/Γ. They must be identical, but may have a small difference in energy-momentum comparable to Γ. This produces new effects resulting from the linear relationship that appears between the S-matrix element and the production cross section of the decay products of the short lived state. An optical theorem for diffraction dissociation processes is proposed. This mechanism also provides a measure of the non-orthogonality between unstable particles that are eigenstates of a non-Hermitian Hamiltonian. Talk presented on the Workshop on Resonances and Time Asymmetric Quantum Theory, Jaca (Spain), 30 May to 4 June 2001     

态|Ψ_n~((2))〉_q的广义非线性等阶N次方H压缩效应

构造了一种新型的多模叠加态 |Ψ(2 )n 〉q=C(R)n |{ -i Z*j }〉q+C(0 )n |{ 0 j}〉q;并首次详细地研究了此量子态的等阶 N次方 H压缩特性 .大量的计算和分析表明 :态 |Ψ(2 )n 〉q是一种多模典型的非经典光场 ;还发现了“相似压缩”等现象     

Quantum Bayesian computation

Quantum Bayesian computation is an emerging field that levers the computational gains available from quantum computers. They promise to provide an exponential speed-up in Bayesian computation. Our article adds to the literature in three ways. First, we describe how quantum von Neumann measurement provides quantum versions of popular machine learning algorithms such as Markov chain Monte Carlo and deep learning that are fundamental to Bayesian learning. Second, we describe quantum data encoding methods needed to implement quantum machine learning including the counterparts to traditional feature extraction and kernel embeddings methods. Third, we show how quantum algorithms naturally calculate Bayesian quantities of interest such as posterior distributions and marginal likelihoods. Our goal then is to show how quantum algorithms solve statistical machine learning problems. On the theoretical side, we provide quantum versions of high dimensional regression, Gaussian processes and stochastic gradient descent. On the empirical side, we apply a quantum FFT algorithm to Chicago house price data. Finally, we conclude with directions for future research.     

四边自由的矩形厚板的自由振动

由于要满足自由边的条件,使得本文所研究的板的分析相当困难。本文采用叠加法完满的解决了这个不易克服的困难,并使得边界条件能满足到任意精度,所取的位移解的每一项都严格满足控制微分方程。     

Rheological characterization of well-defined tetrafluoroethylene/hexafluoropropylene copolymers

The rheology of tetrafluoroethylene/hexafluoropropylene (TFE/HFP) copolymers, also known as Teflon FEP polymers, having different molecular weight and composition (HFP content) was studied by means of a parallel-plate rheometer. Two groups of polymers having different molecular weights with nearly constant polydispersity (around 2.5) were considered; namely, one group having a relatively low melting temperature (amorphous with a high content of HFP) and a second group having a higher melting point (semi-crystalline with a lower content of HFP). The relaxation time spectrum, H(λ), calculated by use of the BSW model (developed for monodisperse linear polymers) followed a scaling relationship in the terminal zone with scaling exponent of 0.13. However, at higher frequencies the model fails to predict adequately the experimental data. The longest relaxation time calculated from both the BSW model and discrete relaxation spectra (λ _i ,g _i ), which was determined by use of a parsimonious fitting software, depends on the molecular weight in a similar way as the zero-shear viscosity does with the well-established scaling factor of 3.4. The critical molecular weight for the onset of entanglements, M _c , was found to be about 100000, a value much higher than those previously reported in literature for other polymers. The rheology of resins in the second group (higher melting point) was found to exhibit a strong dependence on thermal history during oscillatory-shear measurements. The data obtained in experiments at different temperatures without a preheating to a certain value (330°C) exhibited a violation of the time-temperature superposition principle and no well-defined values of the zero-shear viscosity. This is attributed to residual crystallinity even at temperatures well above their melting point (260°C). However, the same experiments with preheating and subsequent cooling to desired temperature resulted into a very good time-temperature scaling. Received: 13 January 1998 Accepted: 6 April 1998     

Viscoelastic characterization of selected foods over an extended frequency range

Three disparate food systems (gummy candy, Mozzarella cheese, and cooked ham) were characterized for their viscoelastic behavior under isothermal conditions over an extended frequency range of 10⁻³ to 10⁴ Hz using broadband viscoelastic spectroscopy (BVS). The materials were tested for any stress-induced fluid flow. However, no evidence of fluid flow was found under the tested frequency range. Validity of time–temperature superposition for the selected materials was also tested and compared with data from BVS.     

Elastic impact on finite Timoshenko beam

In this paper the analytical solutions of the impact of a particle on Timoshenko beams with four kinds of different boundary conditions are obtained according to Navier's idea, which is further developed. The initial values of the impact forces are exactly determined by the momentum conservation law. The propagation of the longitudinal and transverse waves along the beam, especially, the effects of boundary conditions on the characteristics of the reflected waves, are investigated in detail. Some results are compared with those by MSC/NASTRAN.     

高分子材料湿度含量对其力学性能的影响的实验研究

本文从实验的角度对湿度因素影响下的高分子聚合物材料的力学性能进行了研究。选用了尼龙6材料进行了一系列的有关湿度实验，通过不同含湿率下与时间相关的材料性能实验首次从实验上证明高分子聚合物材料存在湿度-时间等效性。即对材料力学性能而言延长作用时间与增加材料含湿率与等效的，并且具体给出了尼龙6材料的湿度-时间等效关系。如该材料在不同含湿率下的广义曲线，本文工作为进一步研究湿度因素影响下的材料性能提供了实验依据。     

局部透射边界和叠加边界的精度分析与比较

本文研究了出平面和平面内波动在局部透射边界和叠加边界的反射系数，在研究中考虑了时空离散化的影响及反射波本身对反射系数的影响．采用一维有限元离散模型讨论了两种边界的阶数对反射系数的影响．通过比较这两种边界的反射系数得出以下结论：局部透射边界在有限元波动模拟中的精度高于叠加边界，且其优越性随着边界阶数的增加而提高。     

炮孔之间爆炸应变场的光力学分析

本文分别运用动态云纹-光弹性和电阻应变量测方法研究了相邻两炮孔之间爆炸应变场。多火花式高速像机和超动态量测系统被用于动态记录。根据动态云纹-光弹条纹分析了应力波的叠加作用,定量地计算了爆炸应力波叠加作用期间内不同时刻地孔连心线上_x(沿连心线方向)和_r(垂直于连心线方向)的分布以及_x在连心线中垂线上的分布。用应变片记录了爆炸应力波叠加作用时连心线上应变-时间示波器轨迹。测量和计算所得炮孔间应力波叠加和衰减的规律与理论分析和动光弹模拟分析结果一致。