162 research outputs found
Nonlocal Transformations for Accelerated Observers
According to the locality postulate of special relativity, the measurements
of physical fields by accelerated observers at a given event in Minkowski
spacetime are related to each other by the representations of the Lorentz
group. Nonlocal extensions of these representations are necessary, however,
once acceleration-induced nonlocality is taken into account. The particular
case of Dirac spinors is treated in detail and the corresponding nonlocal
transformation group is studied.Comment: 8 pages, accepted for publication in Ann. Phys. (Berlin
Vacuum Electrodynamics of Accelerated Systems: Nonlocal Maxwell's Equations
The nonlocal electrodynamics of accelerated systems is discussed in
connection with the development of Lorentz-invariant nonlocal field equations.
Nonlocal Maxwell's equations are presented explicitly for certain linearly
accelerated systems. In general, the field equations remain nonlocal even after
accelerated motion has ceased.Comment: LaTeX file, 23 pages, no figures, accepted for publication in Annalen
der Physi
On the spin-rotation-gravity coupling
The inertial and gravitational properties of intrinsic spin are discussed and
some of the recent work in this area is briefly reviewed. The extension of
relativistic wave equations to accelerated systems and gravitational fields is
critically examined. A nonlocal theory of accelerated observers is presented
and its predictions are compared with observation.Comment: LaTeX, 13 pages, no figures. Submitted to Hehl festschrift (GRG, to
appear
Necessity of Acceleration-Induced Nonlocality
The purpose of this paper is to explain clearly why nonlocality must be an
essential part of the theory of relativity. In the standard local version of
this theory, Lorentz invariance is extended to accelerated observers by
assuming that they are pointwise inertial. This locality postulate is exact
when dealing with phenomena involving classical point particles and rays of
radiation, but breaks down for electromagnetic fields, as field properties in
general cannot be measured instantaneously. The problem is corrected in
nonlocal relativity by supplementing the locality postulate with a certain
average over the past world line of the observer.Comment: 12 pages; v2: improved version accepted for publication in Ann. Phys.
(Berlin
Gravitoelectromagnetism
Gravitoelectromagnetism is briefly reviewed and some recent developments in
this topic are discussed. The stress-energy content of the
gravitoelectromagnetic field is described from different standpoints. In
particular, the gravitational Poynting flux is analyzed and it is shown that
there exists a steady flow of gravitational energy circulating around a
rotating mass.Comment: LaTeX file, no figures, 12 pages, Plenary talk given at EREs2000
(Valladolid, Spain, 6-9 September 2000); to be published in Proc. Spanish
Relativity Meeting, edited by J.-F. Pascual-S\'anchez, L. Flor\'ia, A. San
Miguel, and F. Vicente (World Scientific, 2001
Gravitation and Nonlocality
The physical basis of the standard theory of general relativity is examined
and a nonlocal theory of accelerated observers is described that involves a
natural generalization of the hypothesis of locality. The nonlocal theory is
confronted with experiment via an indirect approach. The implications of the
results for gravitation are briefly discussed.Comment: LaTeX file, no figures, 12 pages. To be published in: Proc. 25th
Johns Hopkins Workshop "2001: A Relativistic Spacetime Odyssey" (World
Scientific, Singapore
Nonlocal Electrodynamics of Linearly Accelerated Systems
The measurement of an electromagnetic radiation field by a linearly
accelerated observer is discussed. The nonlocality of this process is
emphasized. The nonlocal theory of accelerated observers is briefly described
and the consequences of this theory are illustrated using a concrete example
involving the measurement of an incident pulse of radiation by an observer that
experiences uniform acceleration during a limited interval of time.Comment: 24 pages, no figures, expanded version accepted for publication in
Physical Review
Gravitoelectromagnetism: A Brief Review
The main theoretical aspects of gravitoelectromagnetism ("GEM") are
presented. Two basic approaches to this subject are described and the role of
the gravitational Larmor theorem is emphasized. Some of the consequences of GEM
are briefly mentioned.Comment: 15 pages, no figures; v2: slightly improved version published as the
third chapter of The Measurement of Gravitomagnetism: A Challenging
Enterprise, edited by L. Iorio (Nova Science, New York, 2007), pp. 29-3
Modification of the Doppler Effect due to the Helicity-Rotation Coupling
The helicity-rotation coupling and its current empirical basis are examined.
The modification of the Doppler effect due to the coupling of photon spin with
the rotation of the observer is considered in detail in connection with its
applications in the Doppler tracking of spacecraft. Further implications of
this coupling and the possibility of searching for it in the intensity response
of a rotating detector are briefly discussed.Comment: LaTeX file, no figures, 15 pages, amended versio
Acceleration-Induced Nonlocality
The standard relativistic theory of accelerated reference frames in Minkowski
spacetime is described. The measurements of accelerated observers are
considered and the limitations of the standard theory, based on the hypothesis
of locality, are pointed out. The physical principles of the nonlocal theory of
accelerated observers are presented. The implications of the nonlocal theory
are briefly discussed.Comment: LaTeX file, no figures, 9 pages, to appear in: "Advances in General
Relativity and Cosmology", edited by G. Ferrarese, Pitagora (Bologna), 200
- …