The geometrical and quantum-mechanical basis for Davies’ and Unruh’s acceleration temperature is traced to a type of quantum-mechanical (“achronal”) spin. Its existence and definition are based on pairs of causally disjoint accelerated frames. For bosons the expected spin vector of monochromatic particles is given by the “Planckian power” and the “r.m.s. thermal fluctuation” spectra. Under space–time translation the spin direction precesses around that “Planckian” vector. By exhibiting the conserved achronal spin four-current, we extend the identification of achronal spin from single quanta to multiparticle systems. Total achronal spin conservation is also shown to hold, even in the presence of quadratic interactions. In addition, the Lorentz invariance of the acceleration temperature is made explicit by the introduction of pairs of “spherical” Rindler frames.
PAIRED ACCELERATED FRAMES
