Physics of Clocks in Absolute Space-Time
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Refraction and Reflexion According to the Principle of General Covariance
REFRACTION AND REFLEXION ACCORDING TO THE PRINCIPLE OF GENERAL COVARIANCE PATRICK IGLESIAS-ZEMMOUR Abstract. We show how the principle of general covariance introduced by Souriau in smoothly uniform contexts, can be extended to singular situ- ations, considering the group of diffeomorphisms preserving the singular locus. As a proof of concept, we shall see how we get again this way, the laws of reflection and refraction in geometric optics, applying an extended general covariance principle to Riemannian metrics, discontinuous along a hypersurface. Introduction In his paper “Modèle de particule à spin dans le champ électromagnétique et gravitationnel” published in 1974 [Sou74], Jean-Marie Souriau suggests a pre- cise mathematical interpretation of the principle of General Relativity. He names it the Principle of General Covariance. Considering only gravitation field1, he claimed that any material presence in the universe is characterized by a covector defined on the quotient of the set of the Pseudo-Riemannian metrics on space-time, by the group of diffeomorphisms. This principle be- ing, according to Souriau, the correct statement of the Einsteins’s principle of invariance with respect to any change of coordinates. Actually, Souriau’s general covariance principle can be regarded as the active version of Einstein invariance statement, where change of coordinates are interpreted from the active point of view as the action of the group of diffeomorphisms. Now, for reasons relative to the behavior at infinity and results requirement, the group of diffeomorphisms of space-time is reduced to the subgroup of compact supported diffeomorphisms. Date: April 6, 2019. 1991 Mathematics Subject Classification. 83C10, 78A05, 37J10. -
Arxiv:2103.15570V2 [Physics.Hist-Ph] 22 Jun 2021 to This Article in Its Purpose and Content
An Analysis of the Concept of Inertial Frame Boris Čulina Department of Mathematics University of Applied Sciences Velika Gorica Zagrebačka cesta 5, 10410 Velika Gorica, Croatia e-mail: [email protected] Abstract. The concept of inertial frame of reference is analysed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition or it makes them plausible. In particular, the definition shows why physical laws obey space and time symmetries and the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames. keywords: inertial frame of reference, space and time symmetries, the principle of relativity, clock synchronization, physical geometry The concept of inertial frame is a fundamental concept of physics. The opinion of the author is that not enough attention has been paid to such a significant concept, not only in textbooks, but also in the scientific literature. In the scientific literature, many particular issues related to the concept of inertial frame have been addressed, but, as far as the author is aware, a sys- tematic analysis of this concept has not been made. DiSalle’s article [DiS20] in the Stanford Encyclopedia of Philosophy gives an overview of the histori- cal development of the concept of an inertial frame as an essential part of the historical development of physics. -
Type II Familial Synpolydactyly: Report on Two Families with an Emphasis on Variations of Expression
European Journal of Human Genetics (2011) 19, 112–114 & 2011 Macmillan Publishers Limited All rights reserved 1018-4813/11 www.nature.com/ejhg SHORT REPORT Type II familial synpolydactyly: report on two families with an emphasis on variations of expression Mohammad M Al-Qattan*,1 Type II familial synpolydactyly is rare and is known to have variable expression. However, no previous papers have attempted to review these variations. The aim of this paper was to review these variations and show several of these variable expressions in two families. The classic features of type II familial synpolydactyly are bilateral synpolydactyly of the third web spaces of the hands and bilateral synpolydactyly of the fourth web spaces of the feet. Several members of the two families reported in this paper showed the following variations: the third web spaces of the hands showing syndactyly without the polydactyly, normal feet, concurrent polydactyly of the little finger, concurrent clinodactyly of the little finger and the ‘homozygous’ phenotype. It was concluded that variable expressions of type II familial synpolydactyly are common and awareness of such variations is important to clinicians. European Journal of Human Genetics (2011) 19, 112–114; doi:10.1038/ejhg.2010.127; published online 18 August 2010 Keywords: type II familial syndactyly; inherited synpolydactyly; variations of expression INTRODUCTION CASE REPORTS Type II familial synpolydactyly is rare and it has been reported in o30 The first family families.1–12 It is characterized by bilateral synpolydactyly of the third The family had a history of synpolydactyly type II for several web spaces of the hands and bilateral synpolydactyly of the fourth web generations on the mother’s side (Table 1). -
Quantum Mechanics from General Relativity : Particle Probability from Interaction Weighting
Annales de la Fondation Louis de Broglie, Volume 24, 1999 25 Quantum Mechanics From General Relativity : Particle Probability from Interaction Weighting Mendel Sachs Department of Physics State University of New York at Bualo ABSTRACT. Discussion is given to the conceptual and mathemat- ical change from the probability calculus of quantum mechanics to a weighting formalism, when the paradigm change takes place from linear quantum mechanics to the nonlinear, holistic eld theory that accompanies general relativity, as a fundamental theory of matter. This is a change from a nondeterministic, linear theory of an open system of ‘particles’ to a deterministic, nonlinear, holistic eld the- ory of the matter of a closed system. RESUM E. On discute le changement conceptuel et mathematique qui fait passer du calcul des probabilites de la mecanique quantique a un formalisme de ponderation, quand on eectue le changement de paradigme substituantalam ecanique quantique lineairelatheorie de champ holistique non lineaire qui est associee alatheorie de la relativitegenerale, prise comme theorie fondamentale de la matiere. Ce changement mene d’une theorie non deterministe et lineaire decrivant un systeme ouvert de ‘particules’ a une theorie de champ holistique, deterministe et non lineaire, de la matiere constituant un systeme ferme. 1. Introduction. In my view, one of the three most important experimental discov- eries of 20th century physics was the wave nature of matter. [The other two were 1) blackbody radiation and 2) the bending of a beam of s- tarlight as it propagates past the vicinity of the sun]. The wave nature of matter was predicted in the pioneering theoretical studies of L. -
Principle of Relativity in Physics and in Epistemology Guang-Jiong
Principle of Relativity in Physics and in Epistemology Guang-jiong Ni Department of Physics, Fudan University, Shanghai 200433,China Department of Physics , Portland State University, Portland,OR97207,USA (Email: [email protected]) Abstract: The conceptual evolution of principle of relativity in the theory of special relativity is discussed in detail . It is intimately related to a series of difficulties in quantum mechanics, relativistic quantum mechanics and quantum field theory as well as to new predictions about antigravity and tachyonic neutrinos etc. I. Introduction: Two Postulates of Einstein As is well known, the theory of special relativity(SR) was established by Einstein in 1905 on two postulates (see,e.g.,[1]): Postulate 1: All inertial frames are equivalent with respect to all the laws of physics. Postulate 2: The speed of light in empty space always has the same value c. The postulate 1 , usually called as the “principle of relativity” , was accepted by all physicists in 1905 without suspicion whereas the postulate 2 aroused a great surprise among many physicists at that time. The surprise was inevitable and even necessary since SR is a totally new theory out broken from the classical physics. Both postulates are relativistic in essence and intimately related. This is because a law of physics is expressed by certain equation. When we compare its form from one inertial frame to another, a coordinate transformation is needed to check if its form remains invariant. And this Lorentz transformation must be established by the postulate 2 before postulate 1 can have quantitative meaning. Hence, as a metaphor, to propose postulate 1 was just like “ to paint a dragon on the wall” and Einstein brought it to life “by putting in the pupils of its eyes”(before the dragon could fly out of the wall) via the postulate 2[2]. -
Covariance in Physics and Convolutional Neural Networks
Covariance in Physics and Convolutional Neural Networks Miranda C. N. Cheng 1 2 3 Vassilis Anagiannis 2 Maurice Weiler 4 Pim de Haan 5 4 Taco S. Cohen 5 Max Welling 5 Abstract change of coordinates. In his words, the general principle In this proceeding we give an overview of the of covariance states that “The general laws of nature are idea of covariance (or equivariance) featured in to be expressed by equations which hold good for all sys- the recent development of convolutional neural tems of coordinates, that is, are covariant with respect to networks (CNNs). We study the similarities and any substitutions whatever (generally covariant)” (Einstein, differencesbetween the use of covariance in theo- 1916). The rest is history: the incorporation of the math- retical physics and in the CNN context. Addition- ematics of Riemannian geometry in order to achieve gen- ally, we demonstrate that the simple assumption eral covariance and the formulation of the general relativity of covariance, together with the required proper- (GR) theory of gravity. It is important to note that the seem- ties of locality, linearity and weight sharing, is ingly innocent assumption of general covariance is in fact sufficient to uniquely determine the form of the so powerful that it determines GR as the unique theory of convolution. gravity compatible with this principle, and the equivalence principle in particular, up to short-distance corrections1. In a completely different context, it has become clear 1. Covariance and Uniqueness in recent years that a coordinate-independent description It is well-known that the principle of covariance, or coordi- is also desirable for convolutional networks. -
Reconstructing William Craig Explanation of Absolute Time Based on Islamic Philosophy
Reconstructing William Craig Explanation of Absolute Time Based on Islamic Philosophy M. S. Kavyani (1), H. Parsania (2), and H. Razmi (3) Department of Philosophy of Physics, Baqir al Olum University, 37185-787, Qom, I. R. Iran. (2) Permanent Address: Department of Social Sciences, Tehran University, Tehran, I. R. Iran. (3) Permanent Address: Department of Physics, University of Qom, Qom, I. R. Iran. (1) [email protected] (2) [email protected] (3) [email protected] Abstract After the advent of the theory of special relativity, the existence of an absolute time in nature was rejected in physics society. In recent decades, William Craig has endeavored to offer an interpretation of empirical evidences corresponding to theory of relativity with the preservation of an absolute time. His strategy is based on two viewpoints including dynamical theory of time and the Eminent God’s temporal being. After considering and criticizing these two viewpoints, using the well-known overall substantial motion of nature in Islamic philosophy and thus the realization of a general time for all the nature, we have tried to reconstruct Craig argument for an absolute time. Although Craig has considered some evidences from modern physics reasoning on an absolute time, the special advantage of the approach considered here is in this fact that it connects better the existing gap between the metaphysics and the physics of the argument. Keywords: Absolute time; Theory of relativity; William Craig; The dynamical time theory; Islamic Philosophy; Nature overall substantial motion; General time Introduction In classical mechanics, the absolute universal time was considered as the measure of the events chronology and a parameter for determining their priority, posteriority, and simultaneity. -
Lost in the Tensors: Einstein's Struggles with Covariance Principles 1912-1916"
JOHN EARMAN and CLARK GL YMOUR LOST IN THE TENSORS: EINSTEIN'S STRUGGLES WITH COVARIANCE PRINCIPLES 1912-1916" Introduction IN 1912 Einstein began to devote a major portion of his time and energy to an attempt to construct a relativistic theory of gravitation. A strong intimation of the struggle that lay ahead is contained in a letter to Arnold Sommerfeld dated October 29, 1912: At the moment I am working solely on the problem of gravitation and believe 1 will be able to overcome all difficulties with the help of a local, friendly mathemat- ician. But one thing is certain, that I have never worked so hard in my life, and that I have been injected with a great awe of mathematics, which in my naivet~ until now I only viewed as a pure luxury in its subtler forms! Compared to this problem the original theory of relativity is mere child's play.' Einstein's letter contained only a perfunctory reply to a query from Sommerfeld about the Debye-Born theory of specific heats. Obviously disappointed, Som- merfeld wrote to Hilbert: 'My letter to Einstein was in vain . Einstein is evidently so deeply mired in gravitation that he is deaf to everything else? Sommerfeld's words were more prophetic than he could possibly have known; the next three years were to see Einstein deeply mired in gravitation, sometimes seemingly hopelessly so. In large measure, Einstein's struggle resulted from his use and his misuse, his understanding and his misunderstanding of the nature and implications of covariance principles. In brief, considerations of general covariance were bound up with Einstein's motive for seeking a 'generalized' theory of relativity; mis- understandings about the meaning and implementation of this motivation threatened to wreck the search; and in the end, the desire for general covariance helped to bring Einstein back onto the track which led to what we now recognize *Present address c/o Department of Philosophy, University of Minnesota, Minneapolis, Minn, U.S.A. -
Stauer Swiss Tactical Chronograph
WATCH DISPLAY TIMESETTING USING THE CHRONOGRAPH CHRONOGRAPH RESET A. TO SET THE TIME TO SET THE CHRONOGRAPH Chronograph Reset (includes after 1. Pull the crown (part C) out to position “2” This chronograph is able to measure and replacing the battery) B. G. and rotate it to the desired time. display time in 1 second increments up to a 1. Pull the crown (part C) out to position “2”. 2. Once the correct time is set, push the maximum of 59 minutes (part F) and 2. Press the Start/Stop Button (part B) to set 12 C. crown back into “0” (zero) position. The 59 seconds (part G). the Chronograph Second Hand (part F) to the 0 1 2 30 60 Seconds Dial (part A) will start to run. zero position. The chronograph hand can be 1. To start the Chronograph feature, press advanced rapidly by continuously pressing the the Start/Stop Button (part B). To measure 20 10 40 20 TO SET THE DATE Start/Stop Button (part B). split times press the Split/Reset Button (part 20 1. Pull the crown (part C) out to posi- 3. Once the Chronograph Second Hand (part D) to stop counting. tion “1” and rotate it clockwise (away from you) G) has been set to the zero position, push the to the desired date (part E). 2. Press the Split/Reset Button (part D) to F. 6 crown (part C) back into “0” (zero) position. D. 2. Once the correct date is set, push the crown reset the chronograph, and the Chronograph Minute Dial (part F) and the Chronograph To reset the Chronograph Minute (part H) E. -
C300 Abbreviated Instruction
English C300 Abbreviated instruction • To see details of specifications and operations, refer to the instruction manual: C300 instruction manual Component identification Setting the calendar The calendar of this watch does not have to be adjusted manually until Thursday, UTC hour hand UTC minute hand December 31, 2099 including leap years. (perpetual calendar) • Press and hold button B for 2 seconds or more to move the hour and minute Minute hand hands to 12 o'clock position temporarily to see the digital display without their MHP Button B 9:00 1:10 interruption. Press the button again to return them to normal movement. 8:00 Button A 1:20 22 24 2 M 20 4 1. Press and release the lower right button repeatedly to 7:00 1:30 Hour hand 18 6 16 UTC 8 move the mode hand to point to [CAL]. 14 1:40 12 10 24 6:00 20 4 The calendar is indicated on the digital display. PM AM 1:50 16 8 12 0 24-hour hand PM 2:0 A TME CAL 2. Press and release the upper right button or lower left 5:00 SET TM Digital display H.R. R AL-1 4:30 UP button C repeatedly to indicate an area name you want on CHR MODE DOWN AL-2 2:30 00 : AL-3 4 Button M 0 :3 3 the digital display. 0 0 Button C 3: Mode hand 3. Pull out the lower right button M. The calendar indication on the digital display starts blinking and the calendar becomes adjustable. -
Circular Motion Review KEY 1. Define Or Explain the Following: A
Circular Motion Review KEY 1. Define or explain the following: a. Frequency The number of times that an object moves around a circle in a given period of time. b. Period The amount of time needed for an object to move once around a circular path. c. Hertz The standard unit of frequency. 1 cycle/second (or 1 revolution per second) d. Centripetal Force The centrally directed force that causes an object’s tangential velocity to change direction as it moves around a circle. e. Centrifugal Force The imaginary outward force which you feel as you go around a turn in a car. This “force” is a consequence of you being accelerating and your brain interpreting your tendency to move in a straight line as a force. 2. Which of the following is NOT a property of Centripetal Force? a. It is unbalanced b. It always has a real source c. It is directed outward from the center of the circle d. Its magnitude is proportional to mass e. Its magnitude is proportional to the square of speed f. Its magnitude is inversely proportional to the radius of the circle g. It is the amount of force required to turn a particular object in a particular circle 3. If an object is swung by a string in a vertical circle, explain two reasons why the string is most likely to break at the bottom of the circle. 1. The string tension needs to overcome the weight of the object to provide the needed centripetal force. 2. The object is moving the fastest at the bottom unless some force keeps the object at a constant speed as it moves around the circle. -
Relationalism About Mechanics Based on a Minimalist Ontology of Matter
Relationalism about mechanics based on a minimalist ontology of matter Antonio Vassallo,∗ Dirk-André Deckert,† Michael Esfeld‡ Accepted for publication in European Journal for Philosophy of Science This paper elaborates on relationalism about space and time as motivated by a minimalist ontology of the physical world: there are only matter points that are individuated by the distance relations among them, with these re- lations changing. We assess two strategies to combine this ontology with physics, using classical mechanics as example: the Humean strategy adopts the standard, non-relationalist physical theories as they stand and interprets their formal apparatus as the means of bookkeeping of the change of the distance relations instead of committing us to additional elements of the on- tology. The alternative theory strategy seeks to combine the relationalist ontology with a relationalist physical theory that reproduces the predictions of the standard theory in the domain where these are empirically tested. We show that, as things stand, this strategy cannot be accomplished without compromising a minimalist relationalist ontology. Keywords: relationalism, parsimony, atomism, matter points, ontic structural realism, Humeanism, classical mechanics Contents 1 From atomism to relationalism about space and time 2 2 From ontology to physics: two strategies 11 ∗Université de Lausanne, Faculté des lettres, Section de philosophie, 1015 Lausanne, Switzerland. E- arXiv:1609.00277v1 [physics.hist-ph] 1 Sep 2016 mail: [email protected] †Ludwig-Maximilians-Universität