Department of Mathematics, Ohio State University, Columbus, OH 43210, USA

Larmor, radiation, horizon, Rindler, boost, accelerated, measurement, clock

When applied to a dipole source subjected to acceleration which is
violent and long lasting (``extreme acceleration''), Maxwell's
equations predict radiative power which augments Larmor's classical
radiation formula by a nontrivial amount. The physical assumptions
behind this result are made possible by the kinematics of a system of
geometrical clocks whose tickings are controlled by cavities which are
expanding inertially. For the purpose of measuring the radiation from
such a source we take advantage of the physical validity of a
spacetime coordinate framework (``inertially expanding frame'') based
on such clocks. They are compatible and commensurable with the
accelerated clocks of the accelerated source. By contrast, a common
Lorentz frame with its mutually static clocks won't do: it lacks that
commensurability. Inertially expanding clocks give a physicist a
window into the frame of a source with extreme acceleration. He thus
can locate that source and measure radiation from it without being
subjected to such acceleration himself. The conclusion is that
inertially expanding reference frames reveal qualitatively distinct
aspects of nature which would not be accessible if static inertial
frames were the only admissible frames.

**ULRICH H. GERLACH**

**25 February 2003**

- Contents
- INTRODUCTION
- GEOMETRICAL CLOCKS

- PRINCIPLES OF MEASUREMENT
- COMMENSURABILITY

- MEASURING EVENTS VIA RADAR

- IDENTICALLY CONSTRUCTED CLOCKS AS SYMPATHETICALLY RESONATING CAVITIES

- TRANSFER OF TIME ACROSS FROM AN ACCELERATED TO AN INERTIALLY EXPANDING CLOCK
- TRANSFER OF RADAR DATA ACROSS AN EVENT HORIZON
- SUMMARY
- THREE CONCLUSIONS
- Boost Coordinates as Physical and Nonarbitrary
- Conjoint Boost-Invariant Frames as an Arena for Scattering Processes
- Boost Coordinate Frame as a Valid Coordinate Frame in Quantum Field Theory

- ACKNOWLEDGEMENTS
- Bibliography
- About this document ...