RELATIVISTIC TEMPERATURE

A measurement theory for the temperature of relativistic systems is de veloped. The resulting operational approach is shown to be quasi-local and therefore may be applicable in general Riemannian manifolds even when there are temperature gradients which induce heat flows. The surp rising feature of our analysis is that it leads to a bifurcation of th e temperature concept into two distinctly different measurable quantit ies: one a frame invariant scalar field which a local co-moving observ er would tend to identify with the local temperature and employ in the definition of entropy, the other a frame dependent, but nevertheless locally determinable quantity which governs the flow of heat and the a bility to extract work. The two quantities differ by the bookkeeping m ethodology employed to calibrate the thermometer. A simple relationshi p between the two temperatures can be established if a preferred Killi ng vector held is available in the Riemannian manifold.