Locality Hypothesis and the Speed of Light

The locality hypothesis is generally considered necessary for the study of the kinematics of non-inertial systems in special relativity. In this paper we discuss this hypothesis, showing the necessity of an improvement, in order to get a more clear understanding of the various concepts involved, like coordinate velocity and standard velocity of light. Concrete examples are shown, where these concepts are discussed.     

异地时钟同步与时间的度量

介绍了庞加莱等人关于"异地时钟同步"和"相继时间段(绵延)相等"的思考,介绍了爱因斯坦"约定"异地时钟"同时"的方案,以及朗道等人对该方案的发展.我们赞同庞加莱的设想,即对光速传播性质的约定是时间测量的基础,并指出对光速的约定相当于对时空对称性的约定.我们在"约定光速的基础上"给出了钟速同步具有传递性的条件,不仅解决了"异地坐标钟钟速同步"的定义问题,而且解决了"相继时间段相等"的定义问题,证实了庞加莱原初的猜想,简化了时间测量的理论基础.     

On the Fizeau Experiment

Transformations of space and time, depending on a synchronisation parameter e ₁, indicate the existence of a privileged inertial system S ₀. The Lorentz transformations are obtained for a particular e ₁0. No classical experiment on relativity is expected to depend on the choice of e ₁. We show, consistently with expectations, that the result of the Fizeau experiment is explained equally well by theories adopting different values of e ₁. In previous papers we showed that if accelerated reference frames are considered only e ₁=0 remains possible.     

光速在相对论中的核心地位

介绍了关于真空中光速的假定的重要作用,它不仅是相对论理论的基础,而且使人们能够定义同时性并测量空间距离.     

Derivation of the General Case Sagnac Result Using Non-Time-Orthogonal Analysis

The Sagnac time delay and fringe shift dependency on angular velocity and enclosed area are derived from the rotating reference frame using non-time-orthogonal (NTO) tensor analysis. NTO analysis differs from traditional approaches by postulating that the continuous and single valued nature of physical time constrains simultaneity in a rotating frame to be unique (and thus not a matter of convention.) This implies anisotropy in the physical, local speed of light and invalidity of the hypothesis of locality for NTO frames. The Sagnac relationship for the most general case, in which the area enclosed is not circular and does not have the axis of rotation passing through its center, is determined.     

Spatial measures in special relativity do not empirically determine simultaneity relations: A reply to Coleman and Korté

Coleman and Korté have restated and defended an earlier attempt to refute the traditional thesis of the conventionality of simultaneity within special relativity. Here we argue their attempt still fails and respond to criticisms of a paper in which we addressed the inadequacies of their earlier paper. The spatial criterion they use to argue for standard synchronization throughout an inertial frame is merely a definition and provides no demonstration that a unique distant simultaneity relation exists in nature.     

基于同时的相对性对钟慢尺缩效应的再认识

同时的相对性、钟慢效应和尺缩效应是狭义相对论时空观的主要内容.鉴于同时性是时空测量的基础,本文从同时的相对性出发详述了对钟慢效应和尺缩效应的再认识:钟慢效应是运动时钟走时率变慢和校表问题的综合表现,其实质是同时的相对性在时间量度上的直接反映;尺缩效应的实质是同时的相对性在空间量度上的反映,也是不同观测者对同一客观事实的不同时空描述.     

Conventionality of Simultaneity and the Tippe Top Paradox in Relativity

In this paper we critically examine a recently posed paradox (tippe top paradox in relativity) and its suggested resolution. A tippe top when spun on a table, tips over after a few rotations and eventually stands spinning on its stem. The ability of the top to demonstrate this charming feat depends on its geometry (all tops are not tippe tops). To a rocket-bound observer the top geometry should change because of the Lorentz contraction. This gives rise to the possibility that for a sufficiently fast observer the geometry of the top may get altered to such an extent that the top may not tip over! This is certainly paradoxical since a mere change of the observer cannot alter the fact that the top tips over on the table. In an effort to resolve the issue the authors of the paradox compare the equations of motion of the particles of the top from the perspective of the inertial frames of the rocket and the table and observe among other things that (1) the relativity of simultaneity plays an essential role in resolving the paradox and (2) the puzzle in some way is connected with one of the corrolaries of special relativity that the notion of rigidity is inconsistent with the theory. We show here that the question of the incompatibility of the notion of rigidity with special relativity has nothing to do with the current paradox and the role of the lack of synchronization of clocks in the context of the paradox is grossly over-emphasized. The conventionality of simultaneity of special relativity and the notion of the standard (Einstein) synchrony in the Galilean world have been used to throw light on some subtle issues concerning the paradox.     

Universal One-Way Light Speed from a Universal Light Speed Over Closed Paths

This paper gives two complete and elementary proofs that if the speed of light over closed paths has a universal value c, then it is possible to synchronize clocks in such a way that the one-way speed of light is c. The first proof is an elementary version of a recent proof. The second provides high precision experimental evidence that it is possible to synchronize clocks in such a way that the one-way speed of light has a universal value. We also discuss an old incomplete proof by Weyl which is important from an historical perspective.     

既转动又平动车轮的相对论分析

分析了Ｏ′系中一个既转动又平动车轮的相对论效应