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The Scientific Content of the Letters Is Remarkably Rich, Touching on The
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Reviews / Historia Mathematica 33 (2006) 491–508 497 The scientific content of the letters is remarkably rich, touching on the difference between Borel and Lebesgue measures, Baire’s classes of functions, the Borel–Lebesgue lemma, the Weierstrass approximation theorem, set theory and the axiom of choice, extensions of the Cauchy–Goursat theorem for complex functions, de Geöcze’s work on surface area, the Stieltjes integral, invariance of dimension, the Dirichlet problem, and Borel’s integration theory. The correspondence also discusses at length the genesis of Lebesgue’s volumes Leçons sur l’intégration et la recherche des fonctions primitives (1904) and Leçons sur les séries trigonométriques (1906), published in Borel’s Collection de monographies sur la théorie des fonctions. Choquet’s preface is a gem describing Lebesgue’s personality, research style, mistakes, creativity, and priority quarrel with Borel. This invaluable addition to Bru and Dugac’s original publication mitigates the regrets of not finding, in the present book, all 232 letters included in the original edition, and all the annotations (some of which have been shortened). The book contains few illustrations, some of which are surprising: the front and second page of a catalog of the editor Gauthier–Villars (pp. 53–54), and the front and second page of Marie Curie’s Ph.D. thesis (pp. 113–114)! Other images, including photographic portraits of Lebesgue and Borel, facsimiles of Lebesgue’s letters, and various important academic buildings in Paris, are more appropriate. -
From Relativistic Time Dilation to Psychological Time Perception
From relativistic time dilation to psychological time perception: an approach and model, driven by the theory of relativity, to combine the physical time with the time perceived while experiencing different situations. Andrea Conte1,∗ Abstract An approach, supported by a physical model driven by the theory of relativity, is presented. This approach and model tend to conciliate the relativistic view on time dilation with the current models and conclusions on time perception. The model uses energy ratios instead of geometrical transformations to express time dilation. Brain mechanisms like the arousal mechanism and the attention mechanism are interpreted and combined using the model. Matrices of order two are generated to contain the time dilation between two observers, from the point of view of a third observer. The matrices are used to transform an observer time to another observer time. Correlations with the official time dilation equations are given in the appendix. Keywords: Time dilation, Time perception, Definition of time, Lorentz factor, Relativity, Physical time, Psychological time, Psychology of time, Internal clock, Arousal, Attention, Subjective time, Internal flux, External flux, Energy system ∗Corresponding author Email address: [email protected] (Andrea Conte) 1Declarations of interest: none Preprint submitted to PsyArXiv - version 2, revision 1 June 6, 2021 Contents 1 Introduction 3 1.1 The unit of time . 4 1.2 The Lorentz factor . 6 2 Physical model 7 2.1 Energy system . 7 2.2 Internal flux . 7 2.3 Internal flux ratio . 9 2.4 Non-isolated system interaction . 10 2.5 External flux . 11 2.6 External flux ratio . 12 2.7 Total flux . -
Simulating Gamma-Ray Binaries with a Relativistic Extension of RAMSES? A
A&A 560, A79 (2013) Astronomy DOI: 10.1051/0004-6361/201322266 & c ESO 2013 Astrophysics Simulating gamma-ray binaries with a relativistic extension of RAMSES? A. Lamberts1;2, S. Fromang3, G. Dubus1, and R. Teyssier3;4 1 UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041 Grenoble, France e-mail: [email protected] 2 Physics Department, University of Wisconsin-Milwaukee, Milwaukee WI 53211, USA 3 Laboratoire AIM, CEA/DSM - CNRS - Université Paris 7, Irfu/Service d’Astrophysique, CEA-Saclay, 91191 Gif-sur-Yvette, France 4 Institute for Theoretical Physics, University of Zürich, Winterthurestrasse 190, 8057 Zürich, Switzerland Received 11 July 2013 / Accepted 29 September 2013 ABSTRACT Context. Gamma-ray binaries are composed of a massive star and a rotation-powered pulsar with a highly relativistic wind. The collision between the winds from both objects creates a shock structure where particles are accelerated, which results in the observed high-energy emission. Aims. We want to understand the impact of the relativistic nature of the pulsar wind on the structure and stability of the colliding wind region and highlight the differences with colliding winds from massive stars. We focus on how the structure evolves with increasing values of the Lorentz factor of the pulsar wind, keeping in mind that current simulations are unable to reach the expected values of pulsar wind Lorentz factors by orders of magnitude. Methods. We use high-resolution numerical simulations with a relativistic extension to the hydrodynamics code RAMSES we have developed. We perform two-dimensional simulations, and focus on the region close to the binary, where orbital motion can be ne- glected. -
Doppler Boosting and Cosmological Redshift on Relativistic Jets
Doppler Boosting and cosmological redshift on relativistic jets Author: Jordi Fernández Vilana Advisor: Valentí Bosch i Ramon Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain. Abstract: In this study our goal was to identify the possible effects that influence with the Spectral Energy Distribution of a blazar, which we deducted that are Doppler Boosting effect and cosmological redshift. Then we investigated how the spectral energy distribution varies by changing intrinsic parameters of the jet like its Lorentz factor, the angle of the line of sight respect to the jet orientation or the blazar redshift. The obtained results showed a strong enhancing of the Spectral Energy Distribution for nearly 0º angles and high Lorentz factors, while the increase in redshift produced the inverse effect, reducing the normalization of the distribution and moving the peak to lower energies. These two effects compete in the observations of all known blazars and our simple model confirmed the experimental results, that only those blazars with optimal characteristics, if at very high redshift, are suitable to be measured by the actual instruments, making the study of blazars with a high redshift an issue that needs very deep observations at different wavelengths to collect enough data to properly characterize the source population. jet those particles are moving at relativistic speeds, producing I. INTRODUCTION high energy interactions in the process. This scenario produces a wide spectrum of radiation that mainly comes, as we can see in more detail in [2], from Inverse Compton We know that active galactic nuclei or AGN are galaxies scattering. Low energy photons inside the jet are scattered by with an accreting supermassive blackhole in the centre. -
(Special) Relativity
(Special) Relativity With very strong emphasis on electrodynamics and accelerators Better: How can we deal with moving charged particles ? Werner Herr, CERN Reading Material [1 ]R.P. Feynman, Feynman lectures on Physics, Vol. 1 + 2, (Basic Books, 2011). [2 ]A. Einstein, Zur Elektrodynamik bewegter K¨orper, Ann. Phys. 17, (1905). [3 ]L. Landau, E. Lifschitz, The Classical Theory of Fields, Vol2. (Butterworth-Heinemann, 1975) [4 ]J. Freund, Special Relativity, (World Scientific, 2008). [5 ]J.D. Jackson, Classical Electrodynamics (Wiley, 1998 ..) [6 ]J. Hafele and R. Keating, Science 177, (1972) 166. Why Special Relativity ? We have to deal with moving charges in accelerators Electromagnetism and fundamental laws of classical mechanics show inconsistencies Ad hoc introduction of Lorentz force Applied to moving bodies Maxwell’s equations lead to asymmetries [2] not shown in observations of electromagnetic phenomena Classical EM-theory not consistent with Quantum theory Important for beam dynamics and machine design: Longitudinal dynamics (e.g. transition, ...) Collective effects (e.g. space charge, beam-beam, ...) Dynamics and luminosity in colliders Particle lifetime and decay (e.g. µ, π, Z0, Higgs, ...) Synchrotron radiation and light sources ... We need a formalism to get all that ! OUTLINE Principle of Relativity (Newton, Galilei) - Motivation, Ideas and Terminology - Formalism, Examples Principle of Special Relativity (Einstein) - Postulates, Formalism and Consequences - Four-vectors and applications (Electromagnetism and accelerators) § ¤ some slides are for your private study and pleasure and I shall go fast there ¦ ¥ Enjoy yourself .. Setting the scene (terminology) .. To describe an observation and physics laws we use: - Space coordinates: ~x = (x, y, z) (not necessarily Cartesian) - Time: t What is a ”Frame”: - Where we observe physical phenomena and properties as function of their position ~x and time t. -
Einstein, Nordström and the Early Demise of Scalar, Lorentz Covariant Theories of Gravitation
JOHN D. NORTON EINSTEIN, NORDSTRÖM AND THE EARLY DEMISE OF SCALAR, LORENTZ COVARIANT THEORIES OF GRAVITATION 1. INTRODUCTION The advent of the special theory of relativity in 1905 brought many problems for the physics community. One, it seemed, would not be a great source of trouble. It was the problem of reconciling Newtonian gravitation theory with the new theory of space and time. Indeed it seemed that Newtonian theory could be rendered compatible with special relativity by any number of small modifications, each of which would be unlikely to lead to any significant deviations from the empirically testable conse- quences of Newtonian theory.1 Einstein’s response to this problem is now legend. He decided almost immediately to abandon the search for a Lorentz covariant gravitation theory, for he had failed to construct such a theory that was compatible with the equality of inertial and gravitational mass. Positing what he later called the principle of equivalence, he decided that gravitation theory held the key to repairing what he perceived as the defect of the special theory of relativity—its relativity principle failed to apply to accelerated motion. He advanced a novel gravitation theory in which the gravitational potential was the now variable speed of light and in which special relativity held only as a limiting case. It is almost impossible for modern readers to view this story with their vision unclouded by the knowledge that Einstein’s fantastic 1907 speculations would lead to his greatest scientific success, the general theory of relativity. Yet, as we shall see, in 1 In the historical period under consideration, there was no single label for a gravitation theory compat- ible with special relativity. -
Uniform Relativistic Acceleration
Uniform Relativistic Acceleration Benjamin Knorr June 19, 2010 Contents 1 Transformation of acceleration between two reference frames 1 2 Rindler Coordinates 4 2.1 Hyperbolic motion . .4 2.2 The uniformly accelerated reference frame - Rindler coordinates .5 3 Some applications of accelerated motion 8 3.1 Bell's spaceship . .8 3.2 Relation to the Schwarzschild metric . 11 3.3 Black hole thermodynamics . 12 1 Abstract This paper is based on a talk I gave by choice at 06/18/10 within the course Theoretical Physics II: Electrodynamics provided by PD Dr. A. Schiller at Uni- versity of Leipzig in the summer term of 2010. A basic knowledge in special relativity is necessary to be able to understand all argumentations and formulae. First I shortly will revise the transformation of velocities and accelerations. It follows some argumentation about the hyperbolic path a uniformly accelerated particle will take. After this I will introduce the Rindler coordinates. Lastly there will be some examples and (probably the most interesting part of this paper) an outlook of acceleration in GRT. The main sources I used for information are Rindler, W. Relativity, Oxford University Press, 2006, and arXiv:0906.1919v3. Chapter 1 Transformation of acceleration between two reference frames The Lorentz transformation is the basic tool when considering more than one reference frames in special relativity (SR) since it leaves the speed of light c invariant. Between two different reference frames1 it is given by x = γ(X − vT ) (1.1) v t = γ(T − X ) (1.2) c2 By the equivalence -
Massachusetts Institute of Technology Midterm
Massachusetts Institute of Technology Physics Department Physics 8.20 IAP 2005 Special Relativity January 18, 2005 7:30–9:30 pm Midterm Instructions • This exam contains SIX problems – pace yourself accordingly! • You have two hours for this test. Papers will be picked up at 9:30 pm sharp. • The exam is scored on a basis of 100 points. • Please do ALL your work in the white booklets that have been passed out. There are extra booklets available if you need a second. • Please remember to put your name on the front of your exam booklet. • If you have any questions please feel free to ask the proctor(s). 1 2 Information Lorentz transformation (along the xaxis) and its inverse x� = γ(x − βct) x = γ(x� + βct�) y� = y y = y� z� = z z = z� ct� = γ(ct − βx) ct = γ(ct� + βx�) � where β = v/c, and γ = 1/ 1 − β2. Velocity addition (relative motion along the xaxis): � ux − v ux = 2 1 − uxv/c � uy uy = 2 γ(1 − uxv/c ) � uz uz = 2 γ(1 − uxv/c ) Doppler shift Longitudinal � 1 + β ν = ν 1 − β 0 Quadratic equation: ax2 + bx + c = 0 1 � � � x = −b ± b2 − 4ac 2a Binomial expansion: b(b − 1) (1 + a)b = 1 + ba + a 2 + . 2 3 Problem 1 [30 points] Short Answer (a) [4 points] State the postulates upon which Einstein based Special Relativity. (b) [5 points] Outline a derviation of the Lorentz transformation, describing each step in no more than one sentence and omitting all algebra. (c) [2 points] Define proper length and proper time. -
The Challenge of Interstellar Travel the Challenge of Interstellar Travel
The challenge of interstellar travel The challenge of interstellar travel ! Interstellar travel - travel between star systems - presents one overarching challenge: ! The distances between stars are enormous compared with the distances which our current spacecraft have travelled ! Voyager I is the most distant spacecraft, and is just over 100 AU from the Earth ! The closest star system (Alpha Centauri) is 270,000 AU away! ! Also, the speed of light imposes a strict upper limit to how fast a spacecraft can travel (300,000 km/s) ! in reality, only light can travel this fast How long does it take to travel to Alpha Centauri? Propulsion Ion drive Chemical rockets Chemical Nuclear drive Solar sail F = ma ! Newton’s third law. ! Force = mass x acceleration. ! You bring the mass, your engine provides the force, acceleration is the result The constant acceleration case - plus its problems ! Let’s take the case of Alpha Centauri. ! You are provided with an ion thruster. ! You are told that it provides a constant 1g of acceleration. ! Therefore, you keep accelerating until you reach the half way point before reversing the engine and decelerating the rest of the way - coming to a stop at Alpha Cen. ! Sounds easy? Relativity and nature’s speed limit ! What does it take to maintain 1g of accelaration? ! At low velocities compared to light to accelerate a 1000kg spacecraft at 1g (10ms-2) requires 10,000 N of force. ! However, as the velocity of the spacecraft approaches the velocity of light relativity starts to kick in. ! The relativistic mass can be written as γ x mass, where γ is the relativistic Lorentz factor. -
Voigt Transformations in Retrospect: Missed Opportunities?
Voigt transformations in retrospect: missed opportunities? Olga Chashchina Ecole´ Polytechnique, Palaiseau, France∗ Natalya Dudisheva Novosibirsk State University, 630 090, Novosibirsk, Russia† Zurab K. Silagadze Novosibirsk State University and Budker Institute of Nuclear Physics, 630 090, Novosibirsk, Russia.‡ The teaching of modern physics often uses the history of physics as a didactic tool. However, as in this process the history of physics is not something studied but used, there is a danger that the history itself will be distorted in, as Butterfield calls it, a “Whiggish” way, when the present becomes the measure of the past. It is not surprising that reading today a paper written more than a hundred years ago, we can extract much more of it than was actually thought or dreamed by the author himself. We demonstrate this Whiggish approach on the example of Woldemar Voigt’s 1887 paper. From the modern perspective, it may appear that this paper opens a way to both the special relativity and to its anisotropic Finslerian generalization which came into the focus only recently, in relation with the Cohen and Glashow’s very special relativity proposal. With a little imagination, one can connect Voigt’s paper to the notorious Einstein-Poincar´epri- ority dispute, which we believe is a Whiggish late time artifact. We use the related historical circumstances to give a broader view on special relativity, than it is usually anticipated. PACS numbers: 03.30.+p; 1.65.+g Keywords: Special relativity, Very special relativity, Voigt transformations, Einstein-Poincar´epriority dispute I. INTRODUCTION Sometimes Woldemar Voigt, a German physicist, is considered as “Relativity’s forgotten figure” [1]. -
Theory and Experiment in the Quantum-Relativity Revolution
Theory and Experiment in the Quantum-Relativity Revolution expanded version of lecture presented at American Physical Society meeting, 2/14/10 (Abraham Pais History of Physics Prize for 2009) by Stephen G. Brush* Abstract Does new scientific knowledge come from theory (whose predictions are confirmed by experiment) or from experiment (whose results are explained by theory)? Either can happen, depending on whether theory is ahead of experiment or experiment is ahead of theory at a particular time. In the first case, new theoretical hypotheses are made and their predictions are tested by experiments. But even when the predictions are successful, we can’t be sure that some other hypothesis might not have produced the same prediction. In the second case, as in a detective story, there are already enough facts, but several theories have failed to explain them. When a new hypothesis plausibly explains all of the facts, it may be quickly accepted before any further experiments are done. In the quantum-relativity revolution there are examples of both situations. Because of the two-stage development of both relativity (“special,” then “general”) and quantum theory (“old,” then “quantum mechanics”) in the period 1905-1930, we can make a double comparison of acceptance by prediction and by explanation. A curious anti- symmetry is revealed and discussed. _____________ *Distinguished University Professor (Emeritus) of the History of Science, University of Maryland. Home address: 108 Meadowlark Terrace, Glen Mills, PA 19342. Comments welcome. 1 “Science walks forward on two feet, namely theory and experiment. ... Sometimes it is only one foot which is put forward first, sometimes the other, but continuous progress is only made by the use of both – by theorizing and then testing, or by finding new relations in the process of experimenting and then bringing the theoretical foot up and pushing it on beyond, and so on in unending alterations.” Robert A. -
Arxiv:1909.09084V3 [Physics.Hist-Ph] 16 Jul 2020 IX
Defining of three-dimensional acceleration and inertial mass leading to the simple form F=M A of relativistic motion equation Grzegorz M. Koczan∗ Warsaw University of Life Sciences (WULS/SGGW), Poland (Dated: July 20, 2020) Newton's II Law of Dynamics is a law of motion but also a useful definition of force (F=M A) or inertial mass (M =F/A), assuming a definition of acceleration and parallelism of force and accel- eration. In the Special Relativity, out of these three only the description of force (F=dp/dt) does not raise doubts. The greatest problems are posed by mass, which may be invariant rest mass or relativistic mass or even directional mass, like longitudinal mass. This results from breaking the assumption of the parallelism of force and standard acceleration. It turns out that these issues disappear if the relativistic acceleration A is defined by a relativistic velocity subtraction formula. This basic fact is obscured by some subtlety related to the calculation of the relativistic differential of velocity. It is based on the direction of force rather than on a transformation to an instantaneous resting system. The reference to a non-resting system generates a little different velocity subtrac- tion formulae. This approach confirms Oziewicz binary and ternary relative velocities as well as the results of other researchers. Thus, the relativistic three-dimensional acceleration is neither rest acceleration, nor four-acceleration, nor standard acceleration. As a consequence, inertial mass in any direction of the force has the same value as relativistic mass. In other words, the concepts of transverse mass and longitudinal mass, which depend on velocity, have been unified.