Dirac-graphene quasiparticles in strong slow-light pulse

An analytical Volkov's solution of the massless Dirac equation for graphene in the field of slow-light pulse with arbitrary time dependence is obtained. Exact solutions are presented for special cases of monochromatic field and a single-cycle pulse. Following the Fock-Schwinger proper time method, the Green's function for quasiparticles is derived with the account of the influence an external classical electromagnetic wave field.     

8-谈量子力学中的时间反演算子

用概念辨析法对时间反演算子作了较全面深入的讨论，澄清和指明了在时间反演算子的基本性质问题上常见的含混和错误．     

MAGNETOHYDRODYNAMICS'S TYPE EQUATIONS OVER CLIFFORD ALGEBRAS

We study a system of equations modeling the stationary motion of incompressible electrical conducting fluid. Based on methods of Clifford analysis, we rewrite the system of magnetohydrodynamics fluid in the hypercomplex formulation and represent its solution in Clifford operator terms.     

再谈含时Schrdinger方程的求解方法

介绍了线性耦合含时量子系统厄米不变量算符的构造方法，并运用Ｌｅｗｉｓ－Ｒｉｅｓｅｎｆｅｌｄ量子不变量理论得到了一些含时薛定谔方程的精确解．同时也给出了系统时间演化算符的构造方法     

Explicit Form of the Time Operator of a Gaussian Stationary Process

We present the time operator theory in the framework of stationary stochastic processes. The main results of the paper is the derivation of the time operator acting on the Fock space associated with a discrete time gaussian stationary process.     

量子力学中的时间

研究量子力学中的时间问题，既存在理论价值也有实用价值.由于时间在传统量子力学理论中扮演一个参数而不是力学量算符的角色，这使得人们在研究某个物理过程的时间问题时，总要面临如何构造时间算符和计算平均时间的问题.在本文中，我们将系统地给出构造时间算符和求时间的量子力学平均的一般方法. 关键词： 时间算符 平均时间 自共轭性 能量平移     

Time-Symmetric Quantum Mechanics

A time-symmetric formulation of nonrelativistic quantum mechanics is developed by applying two consecutive boundary conditions onto solutions of a time- symmetrized wave equation. From known probabilities in ordinary quantum mechanics, a time-symmetric parameter P₀ is then derived that properly weights the likelihood of any complete sequence of measurement outcomes on a quantum system. The results appear to match standard quantum mechanics, but do so without requiring a time-asymmetric collapse of the wavefunction upon measurement, thereby realigning quantum mechanics with an important fundamental symmetry.     

三种方法求解外场驱动含时谐振子系统的异同

讨论了外场驱动含量谐振子系统的三种解法的异同，发现利用相干态平均方法与量子不变量理论所得结果一致，而利用海森伯运动方程所求结果与上述两种结果相关一个相位因子。     

The Riemann tensor and the Bianchi identity in 5D space–time

The initial assumption of theories with extra dimension is based on the efforts to yield a geometrical interpretation of the gravitation field. In this paper, using an infinitesimal parallel transportation of a vector, we generalize the obtained results in four dimensions to five-dimensional space–time. For this purpose, we first consider the effect of the geometrical structure of 4D space–time on a vector in a round trip of a closed path, which is basically quoted from chapter three of Ref. [5]. If the vector field is a gravitational field, then the required round trip will lead us to an equation which is dynamically governed by the Riemann tensor. We extend this idea to five-dimensional space–time and derive an improved version of Bianchi's identity. By doing tensor contraction on this identity, we obtain field equations in 5D space–time that are compatible with Einstein's field equations in 4D space–time. As an interesting result, we find that when one generalizes the results to 5D space–time, the new field equations imply a constraint on Ricci scalar equations, which might be containing a new physical insight.     

The relationship between naming reaction time and functional MRI parameters in Broca's area

We examined the correlation between behavioural reaction time and functional imaging parameters of the blood oxygenated level dependent (BOLD) response in Broca's Area during a word identification task, and whether the correlation [Magnetic Resonance Imaging 22 (2004) 451-455] varies as a function of four stimulus types: regular words (REGs) (e.g., hint), irregular words (IRRs) (e.g., pint), nonwords (NWs) (e.g., bint), and pseudohomophones (PHs) (e.g., pynt). Participants named letter strings aloud during a functional magnetic resonance imaging study. Naming reaction times were recorded during regular gaps in image acquisition, and BOLD parameters were extracted via a Tikhonov regularized BOLD analysis technique. The results revealed that only PH reaction times were correlated with BOLD width, providing evidence that Broca's area supports phonetic decoding accompanied with phonological lexical access. In addition, we advanced the development of equation-based models of cognitive behaviour and neurophysiology, whereby we showed that the relationship of mathematical independence that exists for predicting REG accuracy, given IRR and NW or PH naming accuracy, was present for naming reaction time, BOLD width, BOLD time to peak, and BOLD intensity. Therefore, we provide converging behavioural and neuroanatomical evidence for a mathematically independent relationship between sight vocabulary and phonetic decoding systems, consistent with a dual-route model of reading.     

Comments on a paper by B. Schulz about Bell's inequalities

Schulz claims to have constructed an actively local stochastic theory which violates Bell's inequality. This is false.     

Free electron gas spectrum parameters of noble gases in dc electric field

Free electron gas is present in every gas, whether it is of atomic or molecular structure. Since the Maxwell spectrum type is the consequence of only thermal motion of constitutive gas particles; therefore, the presence of electric field leads to change the spectrum of charged particles due to their directed motion. However, it has been shown that in the case of occurrence only of elastic interactions between electrons and neutral gas particles (a condition that has been met in the case of weakly ionized noble gases of a relatively huge volume) the deviation of the gas spectrum of free electrons in the electric field from the Maxwell type is negligible. In such a case, the gas spectrum of free electrons is either of Maxwell type (if the frequency collision value is energy-independent) or of Druyvesteyn type (if the mean free electron path value is energy-independent). The Maxwell and Druyvesteyn distribution types are very similar. The only noticeable difference is that the tail of the Maxwell distribution decreases with the energy exponent to the first degree of energy, and the tail of Druyvesteyn distribution with the energy exponent to the second degree of energy. The aim of this paper is to determine whether the gas spectrum of free electrons in weakly ionized noble gases at small values of the product pd (pressure and inter-electrode distance) follows either the Maxwell's or Druyvesteyn's type, as well as to determine the dependence of spectrum parameters on the product pd. It has been established that better results are obtained on the assumption that the mean value of collision frequency is energy-independent.     

Three-dimensional static Green's function for a half space over mixed PEC and dielectric wedges

A pseudo-analytical solution technique is proposed to determine the three-dimensional static Green's function for a half space over mixed perfect electric conductor-dielectric wedges. The governing Poisson's equation is solved, using the Kontorovich–Lebedev and Fourier transforms. The solution, expressed in terms of image contributions, consists of an excitation point source, a set of point images in physical space, and two line images located in complex space for each region of the problem geometry. The validity of the proposed technique is confirmed by comparing our results with the existing analytical solutions and those obtained numerically using the using a finite integration code.     

Time Jitters in Multiple-Core Fiber

Property of soliton propagation is analyzed by using self-companying operator method in every core of multiple-core fiber. The results show that the time jitters of soliton transmission in every core relate to the relative phase among the input solitons in multiple-core fiber.     

Analytical Solution for Single—Mode Time—Dependent Oscillator

Based on the general theory of time-dependent quantum transformation,we use the “time evolution operator” method to solve the single-mode time-dependent oscillator.     

WKB Wave Function of the General Time-Dependent Quadratic Hamiltonian System

We derived the WKB wave function for the general time-dependent quadratic Hamiltonian system using a unitary transformation method. We applied our research to sinusodially drived Caldirola–Kanai oscillator and confirmed that the time evolution of our approximated WKB wave function is similar to that of the exact one. This wave function can be used to analyze the interference between the probability amplitudes contributed by the area of overlap in phase space of quantum states.     

A possible unification of Newton's and Coulomb's forces

We have considered electric charge as the fourth component of the particle momentum in five-dimensional space–time. The fifth dimension has been compactified on a circle with an extremely small radius determined from the fundamental physics constants. First, we have given equations in the framework of five-dimensional special relativity and determined the corresponding reduction to four-dimensional space–time. Then, in order to obtain an appropriate charge-to-mass ratio and to avoid the Fourier modes problem, we have considered the propagation of an off-mass shell particle in the five-dimensional space–time which can be interpreted as the motion of an on-mass shell particle in the four-dimensional world we experience. As an example, we have discussed the five-dimensional kinematic equations associated with the electron-positron annihilation process into two photons. Finally, the consequences on the gravitational interaction between two elementary charged particles has been studied. As a main result, we have obtained a unification of Newton's gravitational and Coulomb's electrostatic forces.     

虚时间分裂算符方法研究溶剂电子转移动力学

在Sumi-Marcus理论中，采用虚时间分裂算符方法研究电子转移动力学．此方法具体应用于计算嗪-1和N,N-二甲基苯胺分子之间的电子转移速率常数．通过计算得到的两种反应物态的平均速率常数和一个长时间的速率常数，揭示了不同的sink函数时的电子转移动力学．在数值模拟过程中还发现了一些新的电子转移特性．