Tomaschitz, R. (2000). Superluminal kinematics in the Milne universe: Causality in the cosmic time order, Celestial Mechanics and Dynamical Astronomy 77, 107-126, 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 particle-tachyon interactions can be based on energy-momentum conservation. We study tachyons in a Robertson-Walker cosmology with linear expansion factor and open, negatively curved 3-space (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 - Robertson-Walker cosmology - hyperbolic space
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Title: |
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Superluminal Kinematics in the Milne Universe: Causality in the Cosmic Time Order |
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Authors: |
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Tomaschitz, Roman |
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Affiliation: |
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AA(Department of Physics, Hiroshima University, 1-3-1 Kagami-yama, Higashi-Hiroshima 739-8526, Japan, roman@fusion.sci.hiroshima-u.ac.jp) |
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Publication: |
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Celestial Mechanics and Dynamical Astronomy, v. 77, Issue 2, p. 107-126 (2000). (CeMDA Homepage) |
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Publication Date: |
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09/2000 |
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Origin: |
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KLUWER; SPRINGER |
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Keywords: |
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TACHYONS, SUPERLUMINAL SIGNALS, COSMIC TIME, CAUSALITY, ROBERTSON-WALKER COSMOLOGY, HYPERBOLIC SPACE, tachyons, superluminal signals, cosmic time, causality, Robertson-Walker cosmology, hyperbolic space |
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DOI: |
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Bibliographic Code: |
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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, energy-momentum conservation in particle-tachyon interactions, positivity of tachyonic energy, absolute space and cosmic time, ether, aether, Robertson–Walker cosmology, hyperbolic 3-space, comoving coordinates and globally geodesic rest frames in the Milne universe
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