Root-Mean-Square Amplitude of Zero-Point Vibrations in a Crystal

Russian Physics Journal - The paper shows that the values of zero-point energy and vibrations of atoms in a crystal determined by the uncertainty principle, depend on the dynamic response of atoms....     

Absolute Instability of FCC Lattice of Rare-Gas Crystals under Pressure

Physics of the Solid State - On the basis of ab initio calculations of the phonon frequencies of compressed rare-gas crystals in the model of deformable and polarizable atoms, dynamic instability...     

Lattice Vibrations of Imidazole Crystals

Abstract

Polarized low-frequency Raman spectra of imidazole single crystals were measured with a He-Ne laser source. A new band at 172 cm^?1 (Bg) was observed. An assignment for the lattice vibrations of imidazole crystals is proposed on the bases of this Raman data and far-infrared spectral data of Perchard and Novak, as well as the preliminary results calculated from Harada's and Williams' potentials.     

Indelible Rules of Josephson Coupling Energy and Zero-Point Energy in High-Tc Cuprates

This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T_c cuprates. This paper also shows that the values of T_c at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models, respectively.     

Zero-Point Energy of Quantum Fields in a Schwarzschild Geometry

The effective Lagrangian and the zero-point (or Casimir) energy is calculated from the zeta-function which is obtained by the heat kernel method using the expansion of (Bormann and Antonsen, 1995). Calculated this way this unavoidable energy contribution is automatically regularised and ready for further investigation. Interesting observations include a large energy contribution (from scalar field and fermionic zero-point fluctuations) that is non-zero as the mass goes to zero, perhaps indicating a topological origin. Also, plots of the contribution of gauge boson fields to the zero-point energy, as a function of radial distance (gravitational field strength) and the size of the gauge boson coupling (gauge field strength) shows great variation, notably the occurrence of resonances.     

六方系InAlGaN晶体的长波长光学声子研究

利用拉曼散射实验方法对六方系InAlGaN晶体的光学声子进行了测量,同时利用修正随机元素同向位移模型对其光学声子与组分的关系进行了理论模拟。结果表明InAlGaN晶体的E₁与A₁光学声子分支都表现为单模行为,测量得到的In_xGa_0.45-xAl_0.55N晶体的A₁(LO)声子与计算结果一致。对In_xAl_0.42-xGa_0.58N晶体的A₁(LO)声子的计算结果与Cros的测量结果进行了对比,两者也相符。     

Immeasurability of Zero-Point Energy in?the?Cosmological Constant Problem

A huge discrepancy between the zero-point energy calculated from quantum theory and the observed quantity in the Universe has been one of the most illusive problems in physics. In order to examine the measurability of zero-point energy, we construct reference frames in a given measurement using observables. Careful and explicit construction of the reference frames surprisingly reveals that not only is the harmonic oscillator fluctuating at the ground level, but so is the reference frame when the measurement is realized. The argument is then extended to examine the measurability of vacuum energy for a quantized electromagnetic field, and it is shown that while zero-point energy calculated from quantum theory diverges to infinity, it is not measurable.     

Mnx Zny Be1-x-y Se半导体混晶中光学声子的研究

在随机元素等位移(MREI)模型的基础上,运用推广后的适用于任意多元混晶的理论,计算了MnxZnyBe1-x-ySe半导体混晶的光学声子性质随组分比的变化关系.比较了四元混晶的理论结果和实验数据,两者符合较好,同时对今后的实验给出了一定程度的指导.     

Planck's Half-Quanta: A History of the Concept of Zero-Point Energy

Max Planck introduced the concept of zero-point energy in spring 1911. In the early struggles to establish the concept of the energy-quantum, it provided a helpful heuristic principle, to guide as well as supplement the efforts of some leading physicists in understanding the laws that applied in the atomic domain. The history and growth of this concept, and its application in the general development of quantum theory during the past many decades are studied under three principal headings: (1) The Birth of the Concept of zero-Point Energy; (2) Does Zero-Point Energy Really Exist? and (3) The Ground State of Quantum Systems.     

ZM模型中零点能修正对核子有效质量的影响

基于ZM模型,讨论了真空零点能的贡献.认为真空零点能不能简单地丢掉,所以零点能中与温度相关的有限部分被分离了出来,并具体讨论了在核物质中这一零点能修正对核子有效质量的影响,发现在高温时它有着非平庸的贡献.     

Spectral Energy Density of Phonons in Metals with Cubic Lattice

Russian Physics Journal - An expression is given for the spectral energy density of acoustic phonons. The basic properties of anharmonic phonons are introduced, and an expression is written for...     

Role of Quasi-Longitudinal and Quasi-Transverse Phonons in the Drag Thermopower of Potassium Crystals at Low Temperatures

Journal of Experimental and Theoretical Physics - We have analyzed the effect of elastic energy anisotropy on the electron–phonon drag and thermoelectric phenomena in potassium crystals. It...     

不同退火温度的ZrO_2 纳米颗粒光学声子和表面吸附分子的拉曼散射研究(英文)

本文对晶粒尺寸在5nm 1 μm范围的纯ZrO2 纳米颗粒进行了拉曼散射研究。除了ZrO2 本征拉曼振动峰外,还有几个新的拉曼振动模式被观察到。我们的结果显示当纳米颗粒尺寸减少时,纳米ZrO2 颗粒的体相特征拉曼峰变弱,而由缺陷,表面和颗粒尺寸引起的相关效应呈强势。晶粒尺寸在1 5纳米左右是引起体相拉曼光谱变化的临界尺寸。晶粒尺寸在1 5纳米以下,其体相拉曼峰发生宽化和峰位移动,以及分别出现在位于1 0 40cm- 1的表面振动峰和1 4个较弱的二阶振动模式。这些结果反映了纳米颗粒的微结构变化与颗粒尺寸和表面效应以及它们之间相互作用的信息     

On the Far Infra Red Excitation of LO Vibrations in Thick Single Crystals

New experiments show that the solution of the complicated problem of Far Infrared (FIR) absorption by crystals of very low symmetry, illuminated at quasi-normal incidence, might have a simple solution, which has been suggested now that a number of spectroscopic studies on monoclinic Triglycine Sulphate (TGS) are available: i) in a first classical approximation where only the strongest bands are considered, the absorption spectrum depends only on the direction of the electric field E of the IR radiation, and Transverse Optic (TO) vibrations are directly excited with electric dipole variations dp parallel to E. ii) in a second approximation looking only at the weakest absorption bands, it depends only on the direction of the wave vector k and Longitudinal Optic (LO) vibrations are excited with dp parallel to k and extinction coefficients 3 orders of magnitude smaller.     

Electrodynamics in the Zero-Point Field: On the Equilibrium Spectral Energy Distribution and the Origin of Inertial Mass

Attempts at an electromagnetic explanation of the inertial mass of charged particles have recently been revived within the framework of Stochastic Electrodynamics, characterized by the adoption of a classical version of the electromagnetic zero-point field (ZPF). Recent claims of progress in this area have to some extent received support from related claims that the classical equilibrium spectrum of charged matter is that of the classically conceived ZPF. The purpose of this note is to suggest that some strong qualifications should accompany these claims. It is pointed out that a classical massless charge cannot acquire mass from nothing as a result of immersion in any EM field, and therefore that the ZPF alone cannot provide a full explanation of inertial mass. Of greater concern, it is observed that the peculiar circumstances under which classical matter is in equilibrium with the ZPF do not concur with observation.     

Infrared and Raman Spectra and lattice Vibrations of Some Ionic Crystals: Fluorides and Oxides

The infrared and Raman spectra of so-called ionic crystals have been subjects of many investigations by chemists as well as by physicists. These spectra have been interpreted on the basis of a dynamical theory on the long-lattice vibrations of the optical branches by Born and Huang [l]. An interpretation of the optically active lattice vibrations of crystals yields important information regarding the interionic interactions in the crystal. The interatomic interactions in the ionic crystals are divided into the short-range repulsive and long-range electrostatic interactions, while those in the molecular crystals arise primarily from the short-range repulsive ones.     

Phonons and photons in crystals

The simultaneous propagation of phonons and photons in an insulator is discussed from both phenomenological and quantum mechanical points of view. A phenomenological form of the energy of an insulator is first supposed from which is obtained the equation of propagation of modes involving nuclei displacements and an electric field. This equation is then studied, mainly in the vicinity of q=0, in order to show how various limits lead to different types of propagation. The phenomenological equations are then justified from a microscopic point of view. The proof goes in two steps. A linear screened response function of the electrons in a solid is first assumed; one then proves that all the coefficients entering into the phenomenological equations may be obtained from the sole knowledge of this response function and of the charge of the nuclei. The existence of the response function is then justified from a many-body point of view. Finally, the necessary relations between the phenomenological coefficients are proved. Some other possible applications of the microscopic equations are also discussed at the end of the paper.     

先进绝热压缩空气储能系统的设计计算

作为一种重要的可再生能源,风能的不稳定性问题亟待解决。压缩空气储能(CAES)系统是解决该问题的一种有效途径。先进绝热压缩空气储能(AA-CAES)系统在传统CAES系统的基础上得到改进,在环境保护、资源节约上有明显的优势。以1.5 MW的AA-CAES为例,介绍了先进绝热压缩空气储能系统的设计过程,并给定具体参数进行计算,对该系统的特性及应用前景进行了分析总结。