Self-consistent description of the inner crust of a neutron star within a realistic semimicroscopic model

The self-consistent semimicroscopic fully quantum approach developed recently for describing the structure of the inner crust of a neutron star within the Wigner-Seitz method is used to perform a systematic calculation of the properties of the system under study. Only the lowest layers of the crust in the vicinity of the point where a phase transition to a uniform state occurs are excluded from our consideration. Use is made of a realistic microscopic model that treats pairing in neutron matter with allowance for corrections of many-body theory to the Bardeen-Cooper-Schrieffer approximation.     

Ultralocal scalar field models

In this paper the quantum theory of ultralocal scalar fields is developed. Such fields are distinguished by the independent temporal development of the field at each spacial point. Although the classical theories fit into the canonical framework, this is not the case for the quantum theories (with the exception of the free field). Explicit operator constructions are given for the field and the Hamiltonian as well as several other operators, and the calculation of the truncated vacuum expectation values is reduced to an associated single degree of freedom calculation. It is shown that construction of the Hamiltonian from the field, as well as the transition from the interaction to the noninteracting theories entails various infinite renormalizations which are made explicit.     

Thermal diffuse scattering in sub-angstrom quantitative electron microscopy-phenomenon,effects and approaches

This paper reviews the recent progress in the following areas. (1) In quantitative high-resolution transmission electron microscopy, the theoretically calculated images usually give better contrast than the experimentally observed ones although all of the factors have been accounted for. This discrepancy is suggested due to thermal diffusely scattered (TDS) electrons, which were not included in the image calculation. The contribution from TDS electrons is especially important if the image resolution is approaching 0.1 nm and beyond with the introduction of Cs corrected microscopes. A more rigorous multislice theory has been developed to account for this effect. (2) We proved that the off-axis holography is an ideal energy filter that even filters away the contribution made by TDS electrons in the electron wave function, but conventional high-resolution microscopy do contain the contribution made by phonon scattered electrons. (3) In electron scattering, most of the existing dynamical theories have been developed under the first order diffuse scattering approximation, thus, they are restricted to cases where the lattice distortion is small. A formal dynamical theory is presented for calculating diffuse scattering with the inclusion of multiple diffuse scattering. By inclusion of a complex potential in dynamical calculation, a rigorous proof is given to show that the high order diffuse scattering are fully recovered in the calculations using the equation derived under the distorted wave Born approximation, and more importantly, the statistical time and structure averages over the distorted crystal lattices are evaluated analytically prior numerical calculation. This conclusion establishes the basis for expanding the applications of the existing theories. (4) The 'frozen lattice' model is a semi-classical approach for calculating electron diffuse scattering in crystals arisen from thermal vibration of crystal atoms. Based on a rigorous quantum mechanical phonon excitation theory, we have proved that the frozen lattice mode is an excellent approximation and no detectable error would be possible under normal experimental conditions.     

Reality,locality, and probability

It is frequently argued that reality and locality are incompatible with the predictions of quantum mechanics. Various investigators have used this as evidence for the existence of hidden variables. However, Bell's inequalities seem to refute this possibility. Since the above arguments are made within the framework of conventional probability theory, we contend that an alternative solution can be found by an extension of this theory. Elaborating on some ideas of I. Pitowski, we show that within the framework of a generalized probability theory, reality, locality, hidden variables, and the predictions of quantum mechanics can be maintained together. Although our principal model in this work is a spin system, there are indications that this program can be extended to more general systems.     

基于鹰鸽量子博弈理论评价科研院所的科技自主创新能力

科研院所的科技自主创新能力是推动国家科技进步和经济发展,应对国际经济危机的主要动力,创建科学、完善的科技创新能力评价方法有助于提升科研院所科技创新能力,并为国家制定科技创新决策提供参考依据。本文基于鹰鸽量子博弈理论,提出了一种评价科研院所自主创新能力的方法。介绍了量子博弈论的各基本要素在科技自主创新体系中所对应的物理内涵,根据鹰鸽量子博弈理论建立了科技自主创新能力评价模型,分析了纠缠度与收益矩阵之间的关系,确立了依靠各参与者在鹰鸽量子博弈中的纠缠度来表征科技自主创新能力的方法。给出了科研院所科技自主创新能力的量子博弈论解释,构建了科技自主创新能力评价指标体系,并确定了评价的合成计算方法,即量子纠缠度的计算方法。最后,以中科院部分研究所为实例进行了科技自主创新能力的评价,并利用主成份分析法和中物院的简单统计方法对得到的数据进行了对比分析,结果证明了提出的方法合理且有可操作性。     

乙炔分子振动光谱的相互作用模式计算

应用量子自陷理论，发展了分子振动光变的相互作用模式方法，对Ｃ２Ｈ２与Ｃ２Ｄ２分子振动光谱进行了计算。计算结果与观测值很符合。     

Self-consistent analysis of a thermally dissipative quantum field system: Korenman's model

Using the Schwinger-Keldysh path-ordering method, a favoured method for doing non-equilibrium quantum field theory, Korenman analyzed a simple model from quantum optics. We study the same model using the recently developed non-equilibrium thermo field dynamics (TFD), and make a comparison of these two methods. TFD can deal with time-dependent non-equilibrium situations caused by the initial conditions being out of equilibrium, while Korenman considered a stationary state maintained by an assumed external pumping mechanism. The explicit TFD calculation at one loop level shows the approach of the system to equilibrium which is described by the master equation derived from the self-consistent renormalization condition. Although both of the methods give practically the same dissipative coefficient in this order of approximation, we would find a larger difference between them in a higher order calculation because of the difference of unperturbative propagators. We also briefly consider the inclusion of a simple pumping mechanism for the system in TFD.     

The Universe and the Quantum Computer

It is first pointed out that there is a common mathematical model for the universe and the quantum computer. The former is called the histories approach to quantum mechanics and the latter is called measurement-based quantum computation. Although a rigorous concrete model for the universe has not been completed, a quantum measure and integration theory has been developed which may be useful for future progress. In this work we show that the quantum integral is the unique functional satisfying certain basic physical and mathematical principles. Since the set of paths (or trajectories) for a quantum computer is finite, this theory is easier to treat and more developed. We observe that the sum of the quantum measures of the paths is unity and the total interference vanishes. Thus, constructive interference is always balanced by an equal amount of destructive interference. As an example we consider a simplified two-slit experiment.     

Light atom scattering from adsorbates at low coverage

A multiple scattering theory is developed for the scattering of light atoms from a disordered adsorbate on a smooth surface. Using gas phase potentials for adatom potentials, excellent agreement is found with data for He scattering from adsorbed Xe and surprisingly good agreement with the extensive data for He scattering from adsorbed CO. The attractive adatom potential must be included in the calculation if quantitative comparison with experimental data is to be made. An important contribution to the total cross section of an adatom are quantum mechanical oscillations similar to glory oscillations in gas phase scattering. The dependence of the total cross section on the incident angle is strongly influenced by the varying number of adatoms seen by the probe.     

简并基态最陡下降微扰理论

本文证明,Cioslowski所引入的一个全新的量子力学计算方案,非简并基态最陡下降微扰理论,通过按对称性选择合适的零级试探波函数后,可以处理简并基态的微扰分裂问题由于最陡下降微扰理论既避免了通常的其他微扰理论需要对各个基矢量无限求和的或求解一组微分方程的缺陷,又具有逐步迭代改善计算结果的优点,本文引进的计算方案可望在原子分子及其他多粒子体系能级的微扰分裂计算中得到广泛应用。 关键词：     

Validity of the semi-classical approach for calculation of the surface excitation parameter

The problem of surface plasmon excitation by moving charges has been elaborated by several different approaches, mainly based on dielectric response theory within either semi-classical or quantum mechanical frameworks. In this work, a comparison of the surface excitation effect between two different frameworks is made by calculation of the differential inverse inelastic mean free path (DIIMFP) and a Monte Carlo simulation of reflection electron energy loss spectroscopy (REELS) spectra. A semi-classical modeling of the interaction between electrons and a solid surface is based on analyzing the work done by moving electrons; the stopping power and inelastic cross section are derived with the induced potential. On the other hand, a quantum mechanical approach is based on derivation of the complex inhomogeneous self-energy of the electrons. The numerical calculation shows that the semi-classical model presents almost the same values of DIIMFP as by the quantum model except at the glancing condition. The simulation of REELS spectra for Ag and SiO(2) as well as a comparison with experimental spectra also confirms that a good agreement with the spectral shape is found among the two simulation results and the experimental data.     

基于量子微扰的AlGaN/GaN异质结波函数半解析求解

基于量子力学微扰理论的分析，得到AlGaN/GaN异质结波函数的半解析模型.给出了模型的理论分析和计算结果.对于相同问题，给出了与差分算法的对照结果.与传统的差分方法相比，半解析方法具有收敛性强、大规模问题计算效率高的特点，更适合作为AlGaN/GaN异质结量子阱的求解算法. 关键词： AlGaN GaN 量子阱 薛定谔方程     

Gauge invariant finite size spectrum of the giant magnon

It is shown that the finite size corrections to the spectrum of the giant magnon solution of classical string theory, computed using the uniform light-cone gauge, are gauge invariant and have physical meaning. This is seen in two ways: from a general argument where the single magnon is made gauge invariant by putting it on an orbifold as a wrapped state obeying the level matching condition as well as all other constraints, and by an explicit calculation where it is shown that physical quantum numbers do not depend on the uniform light-cone gauge parameter. The resulting finite size effects are exponentially small in the R-charge and the exponent (but not the prefactor) agrees with gauge theory computations using the integrable Hubbard model.     

Influence of external magnetic field,finite-size effects and chemical potential on the phase transition of a complex scalar field

A scalar model is built, as a quantum field theory defined on a toroidal topology, to describe a phase transition in films subjected to periodic boundary conditions and influenced by an external and constant magnetic field. Criticality is studied and the relations between the critical temperature, the film thickness, the magnetic field strength and the chemical potential are investigated. Since the model describes a second-order phase transition a comparison with the Ginzburg–Landau theory is made.     

Renormalization of the Quantum Theory of the Solid State

The perturbative structure of a quantum field theory of the solid state, including allradiative corrections, is applied for the calculation of renormaiization factors and counterterms. After a general outline, approximation schemes for the explicit evaluation of renormalization parameters are developed.     

Observers and Locality in Everett Quantum Field Theory

A model for measurement in collapse-free nonrelativistic fermionic quantum field theory is presented. In addition to local propagation and effectively-local interactions, the model incorporates explicit representations of localized observers, thus extending an earlier model of entanglement generation in Everett quantum field theory (Rubin in Found. Phys. 32:1495–1523, 2002). Transformations of the field operators from the Heisenberg picture to the Deutsch-Hayden picture, involving fictitious auxiliary fields, establish the locality of the model. The model is applied to manifestly-local calculations of the results of measurements, using a type of sudden approximation and in the limit of massive systems in narrow-wavepacket states. Detection of the presence of a spin-1/2 system in a given spin state by a freely-moving two-state observer illustrates the features of the model and the nonperturbative computational methodology. With the help of perturbation theory the model is applied to a calculation of the quintessential “nonlocal” quantum phenomenon, spin correlations in the Einstein-Podolsky-Rosen-Bohm experiment.     

甚长波量子阱红外探测器的暗电流特性研究

基于载流子在量子结构中的输运理论研究了甚长波量子阱红外探测器(峰值响应波长15μm，量子阱个数大于40)的载流子的输运性质.研究结果表明，在甚长波量子阱红外探测器中，电流密度一般很低，暗电流主要来源于能量高于势垒边的热激发电子.通过薛定谔方程和泊松方程以及电流的连续性方程的自洽求解，发现外加偏压下电子浓度在甚长波器件各量子阱的分布发生较大变化，电场在整个器件结构上呈非均匀分布，靠近发射极层的势垒承担的电压远远高于均匀分布的情形.平带模型假定电压在器件体系上均匀分布，导致小偏压下的理论计算值远远低于实验值. 关键词： 甚长波量子阱红外探测器 量子波输运 暗电流     

Quantum Chaos,Random Matrices,and Irreversibility in Interacting Many-Body Quantum Systems

The Pauli master equation describes the statistical equilibration of a closed quantum system. Simplifying and generalizing an approach developed in two previous papers, we present a derivation of that equation using concepts developed in quantum chaos and random-matrix theory. We assume that the system consists of subsystems with strong internal mixing. We can then model the system as an ensemble of random matrices. Equilibration results from averaging over the ensemble. The direction of the arrow of time is determined by an (ever-so-small) coupling to the outside world. The master equation holds for sufficiently large times if the average level densities in all subsystems are sufficiently smooth. These conditions are quantified in the text, and leading-order correction terms are given.     

On the independent particle approximation of gauge theories

In this work the independent particle model formulation is studied as a mean-field approximation of gauge theories using the path integral approach in the framework of quantum electrodynamics in 1+1 dimensions. It is shown how a mean-field approximation scheme can be applied to fit an effective potential to an independent particle model, building a straightforward relation between the model and the associated gauge field theory. An example is made considering the problem of massive Dirac fermions on a line, the so called massive Schwinger model. An interesting result is found, indicating a behaviour of screening of the charges in the relativistic limit of strong coupling. A forthcoming application of the method developed to confining potentials in independent quark models for QCD is in view and is briefly discussed.