Tomaschitz, R. (2000). Superluminal kinematics in the Milne universe: Causality in the cosmic time order, Celestial Mechanics and Dynamical Astronomy 77, 107126, DOI: 10.1023/A:1008310222726
Abstract (SpringerLink, SAO/NASA ADS)
The causality of superluminal signal transfer in the galaxy background is scrutinized. The cosmic time of the comoving galaxy frame determines a distinguished time order for events connected by superluminal signals. Every observer can relate his rest frame to the galaxy frame, and compare so the time order of events in his proper time to the cosmic time order. In this way all observers arrive at identical conclusions on the causality of events connected by superluminal signals. The energy of tachyons (superluminal particles) is defined in the comoving galaxy frame analogous to the energy of subluminal particles. It is positive in the galaxy frame and bounded from below in the rest frames of geodesically moving observers, so that particletachyon interactions can be based on energymomentum conservation. We study tachyons in a RobertsonWalker cosmology with linear expansion factor and open, negatively curved 3space (Milne universe). This cosmology admits globally geodesic rest frames for uniformly moving observers, synchronized by Lorentz boosts. In this context we show that no signals can be sent into the past of observers. If an observer emits a tachyonic signal, then the response of a second observer can never reach him prior to the emission, i.e., no predetermination can occur. The proof is based on the positivity of tachyonic energy.
tachyons  superluminal signals  cosmic time  causality  RobertsonWalker cosmology  hyperbolic space
Title: 

Superluminal Kinematics in the Milne Universe: Causality in the Cosmic Time Order 
Authors: 

Tomaschitz, Roman 
Affiliation: 

AA(Department of Physics, Hiroshima University, 131 Kagamiyama, HigashiHiroshima 7398526, Japan, roman@fusion.sci.hiroshimau.ac.jp) 
Publication: 

Celestial Mechanics and Dynamical Astronomy, v. 77, Issue 2, p. 107126 (2000). (CeMDA Homepage) 
Publication Date: 

09/2000 
Origin: 

KLUWER; SPRINGER 
Keywords: 

TACHYONS, SUPERLUMINAL SIGNALS, COSMIC TIME, CAUSALITY, ROBERTSONWALKER COSMOLOGY, HYPERBOLIC SPACE, tachyons, superluminal signals, cosmic time, causality, RobertsonWalker cosmology, hyperbolic space 
DOI: 


Bibliographic Code: 

description: Roman Tomaschitz (2000) Superluminal kinematics in the Milne universe: Causality in the cosmic time order, Celestial Mechanics and Dynamical Astronomy 77, 107.
Keywords: causality of superluminal signal transfer, synchronization of cosmic and proper time, energymomentum conservation in particletachyon interactions, positivity of tachyonic energy, absolute space and cosmic time, ether, aether, Robertson–Walker cosmology, hyperbolic 3space, comoving coordinates and globally geodesic rest frames in the Milne universe
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