用半导体激光器测普朗克常量

本文用小型半导体激光器做单色弱光源,用光电效应法测量普朗克常量,具有精度高、体积小、重量轻、成本低、节约电、使用方便等优点.用光谱分析论证了与相关其他光源比较,半导体激光器光源具有较好的单色性,理论分析了单色光谱线宽度影响测量精确度的原因.     

普朗克常量测定仪的改进

对普朗克常量测定仪的电路部分进行了改造,采用由三端可调稳压器LM317和LM337组成的正负双电源电路,用运算放大器OPA128LM作为电流-电压转换器,电流测量范围可达10-8~10-14A,并总结了在实际电路设计和制作中,提高仪器精度和稳定性的方法.     

测普朗克常量实验数据处理

提出了将实验数据进行分段曲线拟合,计算出曲线方程和交点的方法,并用LabVIEW8.6编写软件辅助数据处理,确定了截止电压U,经线性拟合可方便地得到精确的实验结果.     

趋近平均法测量普朗克常量

为解决光电效应实验中的测量误差较大问题,提出了“趋近平均法”对普朗克常量进行测量,可使测量误差由使用拐点法的34%降至13.5%.     

基于发光二极管的普朗克常量的测量

采用电流表外接法测量发光二极管的伏安特性,确定正向阈值电压;使用多通道光谱仪测量LED的光谱特性,确定与阈值电压对应的LED辐射光的峰值波长,从而计算出普朗克常量.发蓝光、红光及绿光LED测量结果表明h的理论值处于测量值的置信区间内.     

运用Matlab辅助测量普朗克常量

分析了光电效应实验测定普朗克常量传统方法的局限性,运用平移切割法并使用Matlab软件,通过三次样条插值确定"准遏止电压"和最小二乘法拟合,可方便地得到精确的实验结果.     

Determination of the Planck constant by means of a watt balance

The kilogram is the only base unit of the Système International d’unités (SI) still defined by a material artefact. Regarding the past evolution of the SI and the poor knowledge of the stability of the international prototype, its definition is not satisfactory. In the long term, it would be better to move to a definition based either on atomic properties or on fundamental constants. Among the various researches in progress in metrology laboratories, one of the most promising ways seems to be the watt balance. Its principle consists in comparing a mechanical power to an electromagnetic power. This comparison results from a measurement performed in two steps: a static measurement during which the Laplace force acting on a coil driven by a DC current and subjected to an induction field is compared to the weight of a standard mass, and a dynamic measurement where the induced voltage at the terminals of the same coil is determined when it is moved in the same field at a known velocity. The measurement of electrical quantities in terms of the Josephson and the quantum Hall effects then allows the mass unit be linked to the Planck constant. Although the principle of the experiment remains simple and direct, obtaining sufficiently low uncertainty ( 10^-8) implies that devices relevant of various fields of physics must be implemented at their best level. In this paper, a review of the present developments at international level is presented.     

普朗克常量测定系统中实验数据的采集和处理

介绍了在光电效应实验系统改造中,关于实验数据的采集和处理方法。     

Statistical mechanics and the ontological interpretation

To complete our ontological interpretation of quantum theory we have to conclude a treatment of quantum statistical mechanics. The basic concepts in the ontological approach are the particle and the wave function. The density matrix cannot play a fundamental role here. Therefore quantum statistical mechanics will require a further statistical distribution over wave functions in addition to the distribution of particles that have a specified wave function. Ultimately the wave function of the universe will he required, but we show that if the universe in not in thermodynamic equilibrium then it can he treated in terms of weakly interacting large scale constituents that are very nearly independent of each other. In this way we obtain the same results as those of the usual approach within the framework of the ontological interpretation.Professor D. Bohm died on 28 October 1992, shortly after this paper was completed.     

外光电法测量普朗克常量的误差分析与修正

光电效应实验测量得到的普朗克常量与公认普朗克常量值之间存在较大误差,本文通过一系列实验和数据分析,证明了光电效应实验中截止电压对应的光波长并不是滤色片标称的波长,而是小于滤色片标称的波长,是与光电管灵敏度相关的某一起始波长,即起始波长标称不准是误差的主要因素,并设计了相应的改进方案.     

在光电效应实验中用曲率法测普朗克常量

分析了光电效应实验中测试普朗克常量传统的数据处理方法的局限性，提出了运用非线性最小平方拟合的方法进行曲线拟合并用曲率法确定遏止电压Ua，经线性拟合后可获得较精确的普朗克常量。     

Progress on accurate measurement of the Planck constant:Watt balance and counting atoms

The Planck constant h is one of the most significant constants in quantum physics.Recently,the precision measurement of the value of h has been a hot issue due to its important role for the establishment of both a new SI and a revised fundamental physical constant system.Up to date,two approaches,the watt balance and counting atoms,have been employed to determine the Planck constant at a level of several parts in 108.In this paper,the principle and progress on precision measurement of the Planck constant using watt balance and counting atoms at national metrology institutes are reviewed.Further improvement in determining the Planck constant and possible developments of a revised physical constant system in future are discussed.     

The Planck era with a negative cosmological constant and cosmic strings

In the present Letter, we consider the DeBroglie-Bohm interpretation of quantum Friedmann-Robertson-Walker (FRW) models in the presence of a negative cosmological constant and cosmic strings. We compute Bohm's trajectories and quantum potentials for a quantity related to the scale factor.     

The cosmological constant and the color charge at energies of the order of the Planck mass

Quantum gravity as a theory initially exhibiting full conformal invariance is examined. The vacuum expectation value which breaks the symmetry to local Poincaré invariance can produce a cosmological constant as large as the QCD color charge. This result, previously founded through the analysis of the classical solutions by De Alfaro, Fubini, and Furlan, is confirmed by the present calculation of the cosmological constant.     

Unification theory of classical statistical uncertainty relation and quantum uncertainty relation and its applications

General classical statistical uncertainty relation is deduced and generalized to quantum uncertainty relation. We give a general unification theory of the classical statistical and quantum uncertainty relations, and prove that the classical limit of quantum mechanics is just classical statistical mechanics. It is shown that the classical limit of the general quantum uncertainty relation is the general classical uncertainty relation. Also, some specific applications show that the obtained theory is self-consistent and coincides with those from physical experiments.     

浅谈不确定性关系

利用标积概念和统计观点详细清晰地推导了不确定性关系,揭示了教材中用积分不等式证明不确定性关系的缘由,并做了一些讨论.     

Entropic uncertainty relation

Shannon's entropy is used for the formulation of the uncertainty relation. Two concrete examples are solved: the case of dynamically commuting continuous observables, and the case of theh/2 spin projections.     

改进的光电效应测量普朗克常量外推法实验

依据作提出的改进的光电效应外推法实验方案测量了普朗克常量，验证了入射光的频率与“截止电压”的线性关系，得到较好的实验结果．此外，分析了利用爱因斯坦光电方程的截距来测量功函数和确定截止频率的方法误差较大的原因，讨论了现今大学物理实验中两个流行方法的合理性．