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Prof. Rodrigo de Abreu
local time: 2017-10-20 05:56 (+01:00 )
Prof. Rodrigo de Abreu Abstracts
Titles
  • Comment on A One-way Speed of Light Experiment (2009) [Updated 6 years ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:
  • The conceptualization of time and the constancy of the speed of light (2008) [Updated 6 years ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:
  • Special Relativity in Absolute Space: from a contradiction in terms to an obviousness (2006) [Updated 11 days ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:
  • Is the assumption of a special system of reference consistent with Special Relativity? (2005) [Updated 11 days ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:

  • Abstracts Details
  • Comment on A One-way Speed of Light Experiment (2009) [Updated 6 years ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:

    A recent paper published in Am. J. Phys. describes an experiment designed to measure the one-way speed of light.1 Although the experiment is very interesting, in particular to be used in student laboratories, it is in fact determining the two-way speed of light.


  • The conceptualization of time and the constancy of the speed of light (2008) [Updated 6 years ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:

    In this work we show that the null result of the Michelson-Morley experiment in vacuum is deeply
    connected with the notion of time. It can be deduced without any mathematics only from the
    assumption that all good clocks can be used to measure time with the same results, independently
    of the machinery involved in their manufacturing.

    A second important assumption, intrinsic to the very notion of time, is that clocks measure time
    in the same way in different frames, i.e., the notion of time is the same in all inertial frames. Under
    this assumption, we point out that the “postulate” of constancy of the “two-way” speed of light
    in vacuum in all frames independently of the state of motion of the emitting body is also strongly
    related to the concept of time, together with the existence of a limit speed in the “rest frame”. This
    postulate simply results from the construction of clocks where tic-tacs are made by objects traveling
    with the limit speed.


  • Special Relativity in Absolute Space: from a contradiction in terms to an obviousness (2006) [Updated 11 days ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:

    This work deals with the questions of absolute space and relativity. In
    particular, an alternative derivation of the effects described by special
    relativity is provided, which is based on a description that assumes a
    privileged reference frame. The present theory follows the ideas of Lorentz
    and Poincar?, abandoning a strict view of Einstein’s “equivalence” of all
    inertial frames. The meaning of the Principle of Relativity is discussed and
    elucidated, and it is shown that it is not incompatible with the existence of a
    preferred, absolute, frame.

    Most scientists nowadays still consider the basic assumptions of the theory
    proposed here to be plain wrong. Moreover, they tend to see an irreconcilable
    conflict between the Lorentz-Poincar? and the Einstein-Minkowski
    formulations. However, as stated by John Bell [Bell1988], although there is a
    stringent “difference in philosophy” between both views, “the facts of physics
    do not oblige us to accept one philosophy rather than the other”. The validity
    of Bell’s assertion is unambiguously demonstrated, and it is shown how and
    why both approaches do indeed agree in the description of (most of?) the
    physical phenomena. Evidently, the physical meaning of the different
    physical quantities – such as “time”, “speed”, “simultaneity” and
    “synchronization” – is quite different in both programmes. And yet, for
    perplexing it may look at first sight, the present theory, developed under the
    Lorentz-Poincar? assumption of a preferred reference frame, somehow
    encompasses Einstein’s theory. There is no conflict, as there is one theory.

    It must be conceded that what is said in both formulations seems to be
    contradictory, but this is essentially related to a demanding problem of
    language. As a matter of fact, it is revealed that what special relativity says is
    not what usually it is thought it says. By the use of a correct and precise
    language, problems and paradoxes are immediately avoided. Interpretation
    problems only arise because words are used in a sense that is often not correct
    under the chosen description. The core of the problem is related to the largely
    debated question of synchronization of distant clocks. It is stressed that
    reality is not changed by the choices one makes to describe it, so it is not
    changed by the particular way in which the clocks have been set.


  • Is the assumption of a special system of reference consistent with Special Relativity? (2005) [Updated 11 days ago]
    by Rodrigo de Abreu, Vasco Guerra   read the paper:

    In a previous work we have shown that the null result of the Michelson-Morley
    experiment in vacuum is deeply connected with the notion of time. The same is true
    for the the postulate of constancy of the two-way speed of light in vacuum in all
    frames independently of the state of motion of the emitting body. The argumentation
    formerly given is very general and has to be true not only within Special Relativity
    and its ‘equivalence’ of all inertial frames, but as well as in Lorentz-Poincar´e scenario
    of a preferred reference frame. This paper is the second of a trilogy intending to revisit
    the foundations of Special Relativity, and addresses the question of the constancy
    of the one-way speed of light and of the differences and similarities between both
    scenarios. Although they manifestly differ in philosophy, it is debated why and how
    the assumption of a “special system of reference experimentally inaccessible” is indeed
    compatible with Einstein’s Special Relativity, as beautifully outlined and discussed
    by John Bell [1]. This rather trivial statement is still astonishing nowadays to a
    big majority of scientists. The purpose of this work is to bring such assertion into
    perspective, widening the somewhat narrow view of Special Relativity often presented
    in textbooks.