Independence of the isotropy convention for the one-way light speed in relativity

The convention that the one-way velocity of light is isotropic is shown to be independent of the postulates of relativity in a globally Minkowskian continuum, but not in a continuum which is only locally Minkowskian.     

Test of the isotropy of the speed of light using a continuously rotating optical resonator

We report on a test of Lorentz invariance performed by comparing the resonance frequencies of one stationary optical resonator and one continuously rotating on a precision air bearing turntable. Special attention is paid to the control of rotation induced systematic effects. Within the photon sector of the standard model extension, we obtain improved limits on combinations of 8 parameters at a level of a few parts in 10(-16). For the previously least well known parameter we find [EQUATION: SEE TEXT]. Within the Robertson-Mansouri-Sexl test theory, our measurement restricts the isotropy violation parameter [EQUATION: SEE TEXT]. corresponding to an eightfold improvement with respect to previous nonrotating measurements.     

On the feasibility of using X-ray faster-than-light spots to check the isotropy of the speed of light

An experimental method for checking the isotropy of the speed of light is proposed. It is based on excitation of Cherenkov radiation by a virtual electric charge moving with a faster-than-light velocity.     

Noninvariant one-way speed of light and locally equivalent reference frames

We consider an isotropical inertial reference frame (“stationary”) and in it a uniformly rotating circular platform of radiusR. The velocity of light relative to the rim of the platform is calculated and found to have values necessarily different fromc. This remains the same ifR is increased but the peripheral velocity is kept constant. Since by so doing any small piece of the circumference can be considered better and better at rest in a (“moving”) inertial system, the velocity of light relative to this system can be deduced. Noninvariant values are obtained and shown to coincide with the predictions of our recently published “inertial transformations”.     

Determination of the frequency of dielectric isotropy as a function of temperature by light transmission measurements

The frequency f₀ of dielectric isotropy as a function of temperature for a nematic mixture of phenyl benzoates has been determined by light transmission measurements. The activation energy for this process is 0.88 eV.     

Precision test of the isotropy of light propagation

We report on a test of the isotropy of light propagation performed by comparing the resonance frequencies of two orthogonal cryogenic optical resonators subject to Earths rotation over 1yr. The technical aspects of the experiment are discussed and the analysis of the data is presented in detail. For a possible anisotropy of the speed of light c, we obtain c/c₀=(2.6±1.7)×10^-15. Within the general extension of the standard model of particle physics, we extract limits on seven parameters at accuracies down to 10^-15, improving the best previous result by about two orders of magnitude. Within the Robertson–Mansouri–Sexl test theory, this implies an isotropy-violation parameter --1/2=(2.2±1.5)×10^-9, about three times lower than the best previous result. PACS 03.30.+p; 12.60.-i; 06.30.Ft     

Noninvariant one-way velocity of light

After discussing in the first five sections the meaning and the difficulties of the principle of relativity we present a new sel of spacetime transformations between inertial systems (inertial transformations), based on three assumptions: (1) The two-way velocity of light is c in all inertial systems and in all directions; (2) Time dilation effects take place with the usual relativistic factor; (3) Clocks are synchronized in the way chosen by nature itself, e.g., in the Sagnac effect. We show that our new transformation laws can explain the available experimental evidence in spite of the implied noninvariance of the one-way velocity of light.     

利用气体分子相对速度的各向同性导出平均相对速率

首先通过类比发现理想气体分子相对速度分布与速度分布具有相同的函数形式,但是困难在于确定前者的常数因子.我们发现一个常用的公式恰好可以帮助确定这个常数.最终通过类比平均速率的推导直接得到了平均相对速率公式.     

Distant synchrony and the one-way velocity of light

A number of physical processes and experimental procedures are listed which appear to be inexplicable in the context of the conventionality thesis of Reichenbach and Grünbaum. Distant synchrony can be produced by procedures based on the free displacement or rotation of elastic solids. Results are expected to agree with Einstein's definition of distant synchrony (by means of light signals, assuming isotropy). The one-way velocity of light can be measured using a rotating shaft, slotted disks, and one stationary clock.Deceased.     

Test of cosmic spatial isotropy for polarized electrons using a rotatable torsion balance

To test the cosmic spatial isotropy, we use a rotatable torsion balance carrying a transversely spin-polarized ferrimagnetic Dy6Fe23 mass. With a rotation period of 1 h, the period of anisotropy signal is reduced from one sidereal day by about 24 times, and hence the 1/f noise is reduced. Our present experimental results constrain the cosmic anisotropy Hamiltonian H=C(1)sigma(1)+C2sigma(2)+C3sigma(3) (sigma(3) is in the axis of earth rotation) to (C(2)(1)+C(2)(2))(1/2)=(1.1+/-2.0)x10(-20) eV and /C(3)/=(1.1+/-6.0)x10(-19) eV. This improves the previous limits on (C(2)(1)+C(2)(2))(1/2) by 27 times.     

Noninvariant one-way velocity of light and particle collisions

Recently published space-time transformations between inertial systems (different from the Lorentz transformations) are reviewed. Energy and momentum are defined consistently with these new transformation laws. Formally they equal the usual relativistic expressions only in the privileged frame, but numerically they do so in all inertial frames. All the precise experimental data concerning thresholds for inelastic processes, particle masses, and so on, can thus be explained also within this new theoretical framework.     

The speed of light and the speed of neutrinos

The approximate equality in the arrival times of the neutrino and light signals from SN 1987A allows an accurate check of the hypothesis of special relativity that the limiting velocity for all forms of radiation is the same.     

基准微波原子钟

目前,SI基本单位“秒”定义是基于铯133超精细能级跃迁频率,该频率处于微波波段。铯原子钟是直接复现秒定义的基准微波原子钟,它从最初的热铯束钟进化到激光冷却铯原子喷泉钟,总不确定度达到了2×10^-16。随着喷泉钟技术水平的提高,运行可靠性不断提升,基准微波钟不仅可以校准守时钟,还可以驾驭氢钟作为复合守时钟使用,在时频体系中发挥着重要作用。     

The measurement of the speed of light

In order that a measurement of one item against another item is significant it must be verified that these items ARE INDEPENDENT of each other. It can readily be shown that the unit of m/s is proportional to the speed of light and hence measurements of the speed of light in units of m/s are basically flawed. Some aspects of the speed of light not being a constant are discussed.     

Condition for far-zone spectral isotropy of an electromagnetic light wave on weak scattering

The far-zone spectral isotropy of an electromagnetic light wave on scattering has been discussed. It is shown that a sufficient condition for the far-zone spectral isotropy of an electromagnetic light wave on scattering can be expressed by the following two requirements: the two-point correlation function of the dielectric susceptibility of the scattering medium obeys the so-called scaling law, and the normalized spectrum of the incident light wave has the same distribution along the two perpendicular directions.     

量子频标中的原子物理

频率是自然界中测量得最准的物理量.量子频标是频率的测量标准,它是利用原子跃迁谱线的稳定而准确的频率作为参考频率.频标研究中存在几乎所有的原子物理问题,如原子结构与光谱、原子与电磁场的相互作用以及原子碰撞等问题值得深入研究.本文就量子频标的基本原理和应用,量子频标中存在的原子物理问题做以简要评述.