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Showing papers on "Special relativity (alternative formulations) published in 2004"


Book ChapterDOI
TL;DR: In this paper, the relation between Doubly Special Relativity and quantum gravity, the formal structure of DSR proposal based on Poincar\'e algebra and non-commutative Minkowski space-time, as well us some results and puzzles related to DSR phenomenology.
Abstract: In these notes, based on the lectures given at 40th Winter School on Theoretical Physics, I review some aspects of Doubly Special Relativity (DSR). In particular, I discuss relation between DSR and quantum gravity, the formal structure of DSR proposal based on $\kappa$-Poincar\'e algebra and non-commutative $\kappa$-Minkowski space-time, as well us some results and puzzles related to DSR phenomenology.

207 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that gravity in 2+1 dimensions coupled to point particles provides a nontrivial example of doubly special relativity (DSR), which is obtained by interpretation of previous results in the field and by exhibiting an explicit transformation between the phase space algebra for one particle in 2 + 1 gravity found by Matschull and Welling and the corresponding DSR algebra.
Abstract: It is shown that gravity in 2+1 dimensions coupled to point particles provides a nontrivial example of doubly special relativity (DSR). This result is obtained by interpretation of previous results in the field and by exhibiting an explicit transformation between the phase space algebra for one particle in 2+1 gravity found by Matschull and Welling and the corresponding DSR algebra. The identification of 2+1 gravity as a DSR system answers a number of questions concerning the latter, and resolves the ambiguity of the basis of the algebra of observables. Based on this observation a heuristic argument is made that the algebra of symmetries of ultra high energy particle kinematics in 3+1 dimensions is described by some DSR theory.

162 citations


Journal ArticleDOI
01 Oct 2004-Analysis
TL;DR: The authors argued that the Past is Dead hypothesis is not tenable if combined with Special Relativity and that, on the contrary, special Relativity supports No Futurism or Presentism at the expense of the Parmenidean position that past and future are both real.
Abstract: In 'How do we know it is now now?' David Braddon-Mitchell (2004) develops an objection to No Futurism (also known as the Growing Block theory) that the past is real but the future is not.1 He notes my response to this, namely that the past, although real, is lifeless and (a fortiori?) lacking in sentience. He argues, however, that this response, which I call the Past is Dead hypothesis is not tenable if combined with Special Relativity. My purpose in this reply is to argue that, on the contrary, Special Relativity supports No Futurism or Presentism at the expense of the Parmenidean position that past and future are both real.

81 citations


01 Dec 2004
TL;DR: In this paper, the authors argue that the assumption that there could be superluminal signals in relativity gives rise to well-known paradoxes, and that this situation is not nearly as dire as it appears at first sight.
Abstract: It is widely believed that relativity -- both special and general -- requires that no physical signal travel at a speed faster than that of light. For instance, the assumption that there could be superluminal signals in relativity gives rise to well-known paradoxes. We suggest that this situation is not nearly as dire as it appears at first sight. Indeed, we shall argue that relativity is virtually as viable and self-consistent as a physical theory in the presence of superluminal signals as it is with such signals excluded.

79 citations


Journal ArticleDOI
TL;DR: In this article, a Dirac equation that is consistent with one of the recently-proposed schemes for a "doubly special relativity", a relativity with both an observerindependent velocity scale and an observer-independent length/momentum scale was constructed.
Abstract: We construct a Dirac equation that is consistent with one of the recently-proposed schemes for a 'doubly special relativity', a relativity with both an observer-independent velocity scale (still naturally identified with the speed-of-light constant) and an observer-independent length/momentum scale (possibly given by the Planck length/momentum). We find that the introduction of the second observer-independent scale only induces a mild deformation of the structure of Dirac spinors. We also show that our modified Dirac equation naturally arises in constructing a Dirac equation in the ?-Minkowski noncommutative spacetime. Previous, more heuristic studies had already argued for a possible role of doubly special relativity in ?-Minkowski, but remained vague on the nature of the consistency requirements that should be implemented in order to assure the observer-independence of the two scales. We find that a key role is played by the choice of a differential calculus in ?-Minkowski. A much-studied choice of the differential calculus does lead to our doubly special relativity Dirac equation, but a different scenario is encountered for another popular choice of differential calculus.

51 citations


Journal ArticleDOI
TL;DR: In this paper, the authors propose a reakcni kinetika v dvakrat specialni teorii relativity: stabilita fotonu, reakce vysokoenergetickych kosmickych protonu a gamma fotonus s kos mickym mikrovlnovym pozadim.
Abstract: Reakcni kinetika v dvakrat specialni teorii relativity, porovnavani reakcnich prahu s reakcnimi prahy v specialni teorii relativity: stabilita fotonu, reakce vysokoenergetickych kosmickych protonu a gamma fotonu s kosmickym mikrovlnovym pozadim.

42 citations


Book ChapterDOI
TL;DR: A new approach to the dynamics of the universe based on work by O Murchadha, Foster, Anderson and the author is presented in this paper, where the only kinematics presupposed is the spatial geometry needed to define configuration spaces in purely relational terms.
Abstract: A new approach to the dynamics of the universe based on work by O Murchadha, Foster, Anderson and the author is presented. The only kinematics presupposed is the spatial geometry needed to define configuration spaces in purely relational terms. A new formulation of the relativity principle based on Poincare’s analysis of the problem of absolute and relative motion (Mach’s principle) is given. The entire dynamics is based on shape and nothing else. It leads to much stronger predictions than standard Newtonian theory. For the dynamics of Riemannian 3-geometries on which matter fields also evolve, implementation of the new relativity principle establishes unexpected links between special relativity, general relativity and the gauge principle. They all emerge together as a self-consistent complex from a unified and completely relational approach to dynamics. A connection between time and scale invariance is established. In particular, the representation of general relativity as evolution of the shape of space leads to a unique dynamical definition of simultaneity. This opens up the prospect of a solution of the problem of time in quantum gravity on the basis of a fundamental dynamical principle.

37 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the algebra of the recently proposed Triply Special Relativity can be brought to a linear (i.e., Lie) form by a correct identification of its generators.
Abstract: We show that the algebra of the recently proposed Triply Special Relativity can be brought to a linear (ie, Lie) form by a correct identification of its generators. The resulting Lie algebra is the stable form proposed by Vilela Mendes a decade ago, itself a reapparition of Yang's algebra, dating from 1947. As a corollary we assure that, within the Lie algebra framework, there is no Quadruply Special Relativity.

30 citations


Journal ArticleDOI
TL;DR: In this paper, the authors propose a consistent framework to interpret Deformed Special Relativity (DSR) physics and introduce the concept of a pentamomentum and to take into account the renormalization of the DSR deformation parameter kappa.
Abstract: In many different ways, Deformed Special Relativity (DSR) has been argued to provide an effective limit of quantum gravity in almost-flat regime. Unfortunately DSR is up to now plagued by many conceptual problems (in particular how it describes macroscopic objects) which forbids a definitive physical interpretation and clear predictions. Here we propose a consistent framework to interpret DSR. We extend the principle of relativity: the same way that Special Relativity showed us that the definition of a reference frame requires to specify its speed, we show that DSR implies that we must also take into account its mass. We further advocate a 5-dimensional point of view on DSR physics and the extension of the kinematical symmetry from the Poincare group to the Poincare-de Sitter group (ISO(4,1)). This leads us to introduce the concept of a pentamomentum and to take into account the renormalization of the DSR deformation parameter kappa. This allows the resolution of the "soccer ball problem" (definition of many-particle-states) and provides a physical interpretation of the non-commutativity and non-associativity of the addition the relativistic quadrimomentum.

29 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that depending on the direction of deformation of κ -Poincare algebra (time-like, space-like or light-like), the associated phase spaces of a single particle in Doubly Special Relativity theories have the energy-momentum spaces of the form of de Sitter, anti-de Sitter and flat space, respectively.

26 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe the materials they have created to aid in the teaching and learning of introductory special relativity, which is the first topic presented in the modern physics section of introductory physics courses and in the sophomore-level modern physics course.
Abstract: In a recent paper in this journal1 we presented work on the creation and use of Physlet-based2 exercises to teach physical and wave optics. Since then we have developed ready-to-run exercises for introductory physics3,4 and have developed Physlet-based exercises for more advanced topics such as quantum mechanics. In this paper we describe the materials we have created to aid in the teaching and learning of introductory special relativity. There are many reasons to focus on special relativity. Special relativity is the first topic presented in the modern physics section of introductory physics courses and in the sophomore-level modern physics course. It is full of (apparent) paradoxes, and like quantum mechanics, is one of the intriguing theories that continues to captivate students' interest in physics. In addition, because special relativity focuses on abstract concepts, the visualization that Physlet-based material provides is especially valuable.

Journal ArticleDOI
TL;DR: In this article, the authors analyze the Fantappie group and its properties in connection with Cantorian space-time, focusing on the possibility of extending special relativity and the cosmological consequences of such extension appear relevant, since the model of the Big Bang and that of stationary state become compatible.
Abstract: In this paper, we will analyze the Fantappie group and its properties in connection with Cantorian space–time. Our attention will be focused on the possibility of extending special relativity. The cosmological consequences of such extension appear relevant, since thanks to the Fantappie group, the model of the Big Bang and that of stationary state become compatible. In particular, if we abandon the idea of the existence of only one time gauge, since we do not see the whole Universe but only a projection, the two models become compatible. In the end we will see the effects of the projective fractal geometry also on the galactic and extra-galactic dynamics.

Posted Content
TL;DR: Deformed special Relativity (DSR) is obtained by imposing a maximal energy to Special Relativity and deforming the Lorentz symmetry (more exactly the Poincar\'e symmetry) to accommodate this requirement.
Abstract: Deformed Special Relativity (DSR) is obtained by imposing a maximal energy to Special Relativity and deforming the Lorentz symmetry (more exactly the Poincar\'e symmetry) to accommodate this requirement. One can apply the same procedure deforming the Galilean symmetry in order to impose a maximal speed (the speed of light). This leads to a non-commutative space structure, to the expected deformations of composition of speed and conservation of energy-momentum. In doing so, one runs into most of the ambiguities that one stumbles onto in the DSR context. However, this time, Special Relativity is there to tell us what is the underlying physics, in such a way that we can understand and interpret these ambiguities. We use these insights to comment on the physics of DSR.

Journal ArticleDOI
Oliver Passon1
TL;DR: In the spirit and style of John S Bell's well-known paper on How to teach special relativity, it is argued that a Bohmian pedagogy provides a very useful tool to illustrate the relation between classical and quantum physics and illuminates the peculiar features of the latter as discussed by the authors.
Abstract: In the spirit and style of John S Bell's well-known paper on How to teach special relativity [1] it is argued that a 'Bohmian pedagogy' provides a very useful tool to illustrate the relation between classical and quantum physics and illuminates the peculiar features of the latter.


Posted Content
TL;DR: In this paper, a de Sitter invariant special relativity with two universal constants of speed c and length R based on the principle of relativity and the postulate of universal constantsc and R on de Satter space with Beltrami metric was proposed.
Abstract: Physics Department, Tsinghua University, Beijing 100084, China.(Dated: June 17, 2004)Weakening the Euclidean assumption in special relativity and the coordinate-independence hypothesis in general relativity for the de Sitter space, we proposea de Sitter invariant special relativity with two universal constants of speed c andlength R based on the principle of relativity and the postulate of universal constantsc and R on de Sitter space with Beltrami metric. We also propose a postulate onthe origin of the inertial motions and inertial systems as a base of the principle ofrelativity. We show that the Beltrami-de Sitter space provides such a model that theorigin of inertia should be determined by the cosmological constant Λ if the length Ris linked with Λ. In addition, via the ‘gnomonic’ projection the uniform straight-linemotion on Beltrami-de Sitter space is linked with the uniform motion along a great‘circle’ on de Sitter space embedded in 5-d Minkowski space.


Journal ArticleDOI
TL;DR: The physical meaning of the line element in general relativity was discussed in this paper, where it was shown that the physical spatial and temporal coordinates of a given observer are related by Lorentz transformations even though those frames are accelerating or exist in strong gravitational fields.
Abstract: This paper comments on the physical meaning of the line element in general relativity. We emphasize that, generally speaking, physical spatial and temporal coordinates (those with direct metrical significance) exist only in the immediate neighborhood of a given observer, and that the physical coordinates in different reference frames are related by Lorentz transformations (as in special relativity) even though those frames are accelerating or exist in strong gravitational fields.


Posted Content
TL;DR: In this article, the authors argue that the fundamental theory of special relativity has to be consistent with the existence of the massive universe, and with the effects of its gravitational interaction on local physics.
Abstract: In this paper I argue for a reassessment of special relativity. The fundamental theory of relativity applicable in this Universe has to be consistent with the existence of the massive Universe, and with the effects of its gravitational interaction on local physics. A reanalysis of the situation suggests that all relativistic effects that are presently attributed to kinematics of relative motion in flat space-time are in fact gravitational effects of the nearly homogeneous and isotropic Universe. The correct theory of relativity is the one with a preferred cosmic rest frame. Yet, the theory preserves Lorentz invariance. I outline the new theory of Cosmic Relativity, and its implications to local physics, especially to physics of clocks and to quantum physics. This theory is generally applicable to inertial and noninertial motion. Most significanlty, experimental evidence support and favour Cosmic Relativity. There are observed effects that can be consistently explained only within Cosmic Relativity. The most amazing of these is the dependence of the time dilation of clocks on their `absolute' velocity relative to the cosmic rest frame. Important effects on quantum systems include the physical cause of the Thomas precession responsible for part of the spectral fine structure, and the phase changes responsible for the spin-statistics connection. At a deeper level it is conlcuded that relativity in flat space-time with matter reiterates Mach's principle. There will not be any relativistic effect in an empty Universe.

Posted Content
TL;DR: In this article, a novel experiment to test special relativity via Lorentz symmetry has become factible thanks to three recent technological achievements: huge Michelson-like set-up with arms 3 km long (Virgo) and 4 km (Ligo) with beam paths respectively reaching 120 km and 200 km through multiple reflections, ultrashort laser pulses of 10-15 s and ultrafast detectors of 10 -12 s resolution.
Abstract: A novel experiment to test special relativity via Lorentz symmetry has become factible thanks to three recent technological achievements: huge Michelson-like set-up with arms 3 km long (Virgo) and 4 km (Ligo) with beam paths respectively reaching 120 km and 200 km through multiple reflections, ultrashort laser pulses of 10-15 s and ultrafast detectors of 10-12 s resolution. The alliance of these three elements would allow checking the equality of the time-of-flight of the two orthogonal beams with a resolution high enough to allow prospecting in a novel way the equivalency of inertial system postulated in special relativity. In effect, for a beam path length of 120 or 200 km and a net drift velocity of earth of 370 km/s relative to the cosmic microwave background CMB), a classical analysis predicts a time-of-flight difference of the order of 10 ns between the two orthogonal beams, while relativity infers them to be equal. So, what is under scrutiny is the exhaustivity of the electromagnetic equivalency of inertial systems. A null time-of-flight difference would strengthen the Lorentz symmetry, while a non null result would bring a threshold to the equivalency of inertial systems and at the same time would provide a tool to define their speed, which should be equal to that relative to the CMB for being congruent.

01 Jan 2004
TL;DR: In this article, a novel perspective of probing universal character of gravity is expounded, which suggests that the universal nature of force further suggests that it is intrinsically attractive, self interactive and higher dimensional.
Abstract: I wish to expound a novel perspective of probing universal character of gravity. To begin with, inclusion of zero mass particle in mechanics leads to special relativity while its interaction with a universal force shared by all particles leads to general relativity. The universal nature of force further suggests that it is intrinsically attractive, self interactive and higher dimensional. I argue that the principle of universality could serve as a good guide for future directions.

Journal ArticleDOI
TL;DR: In this paper, the authors presented a procedure to obtain exact analytical solutions of field equations for spherically symmetric self-gravitating distribution of anisotropic matter in bimetric theory of gravitation.
Abstract: In this paper we have presented a procedure to obtain exact analytical solutions of field equations for spherically symmetric self-gravitating distribution of anisotropic matter in bimetric theory of gravitation. The solution agrees with the Einstein's general relativity for a physical system compared to the size of universe such as the solar system.

Journal ArticleDOI
21 Oct 2004-Nature
TL;DR: A measurement of the ‘frame-dragging’ effect of the spinning mass of the Earth confirms Einstein's theory of general relativity.
Abstract: According to a prediction of general relativity, the spinning mass of the Earth affects the motion of satellites. A measurement of this 'frame-dragging' effect confirms Einstein's theory.



Journal ArticleDOI
TL;DR: This article analyzed Albert Einstein's derivation of the Lorentz transformations in his paper, "Zur Elektrodynamik bewegter Korper", originally published in 1905.
Abstract: We analyze Albert Einstein’s derivation of the Lorentz transformations in his paper, “Zur Elektrodynamik bewegter Korper,” originally published in 1905. The analysis clarifies various misunderstandings in the secondary literature and reveals reasons why Einstein’s work entailed interpretive difficulties.

Dissertation
01 Jan 2004
TL;DR: In this paper, the authors propose a method to solve the problem of "uniformity" and "uncertainty" in the context of health care, and propose a solution.
Abstract: vi

Journal ArticleDOI
TL;DR: An overview of numerical methods for special relativistic hydrodynamics (SRHD) is given in this paper, where the exact solution for the SRHD Riemann problem is described.
Abstract: We give an overview of numerical methods for special relativistic hydrodynamics (SRHD). First, a short summary of special relativity is given. Next, the SRHD equations are introduced. The exact solution for the SRHD Riemann problem is described. This solution is used in a Godunov scheme to compute solutions for two test problems. A third test problem is used to show non-convergent behaviour of the numerical solution at the location of the contact discontinuity. Finally, a short description of numerical methods used so far in SRHD is given

Book ChapterDOI
TL;DR: In this paper, simple ideas that shed new light on the physics of rotation as it concerns two famous experiments: The Wilson and Wilson, and the Michelson and Morley experiments.
Abstract: Simple ideas that shed new light on the physics of rotation as it concerns two famous experiments: The Wilson and Wilson, and the Michelson and Morley experiments.