A linear wave field in its Minkowski ground state is analyzed heuristically by two observers, one inertial, the other accelerating in a linear and uniform way. Relative to the accelerated observer, the zero-point oscillations of each Minkowski plane wave mode have an unusual Fourier spectrum. Its intensity is (i) the same for all plane wave modes, (ii) isotropic, and (iii) that of a thermal ambience (relative to the accelerated frame). The temperature of this ambience is given by the Davies-Unruh formula (...) kT=(ħ/2π)(g/c). The existence of this ambience is incompatible with the requirement that the laws of nature be formulated in terms of tensors. (shrink)

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, and 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 inertial frames were the only admissible frames. (shrink)

The only observational quantity which quantum mechanics needs to address islocation. The typical primitive observation on a microsystem (e.g., photon) isdetection at alocation (e.g., by a photomultiplier “looking at” a grating). To analyze an experiment, (a) form a conceptual ensemble of replicas of it, (b) assign a wave function (in “position representation”) to its initial condition, (c) evolve the wave function by the Schrödinger equation (known, once and for all, as a function of the system's composition), (d) compute the probability (...) for particle detection at various times and places. The initial wave function is chosen on the basis of experience with such treatments. Key experiments are thus treated: (i) time-of-flight, (ii) Stern-Gerlach, (iii) Franck-Hertz, (iv) photon recoil, (v) photoionization. Quantum states, dynamical variables, and measurements, and the usual postulates about them, are superfluous. The explicit treatments are nonrelativistic; the existence of relativistic generalizations is left open. (shrink)