Three Views of a Secret in Relativistic Thermodynamics

It has been shown three different views in relativistic thermodynamics can be derived from the basic formulation proposed by van Kampen and Israel. The way to decompose energy-momentum into the reversible and irreversible parts is not uniquely determined, and different choices result in different views. The effect of difference in the definition of a finite volume is also considered.Comment: 4 pages, no figure

Lorentz Transform of Black Body Radiation Temperature

The Lorentz transform of black body radiation has been investigated from the view point of relativistic statistical mechanics. The result shows that the well known expression with the directional temperature can be derived based on the inverse temperature four vector. The directional temperature in the past literature was the result of mathematical manipulation and its physical meaning is not clear. The inverse temperature four vector has, in contrast, clear meaning to understand relativistic thermodynamical processes.Comment: 6 pages, no figur

Thermodynamics of Extended Bodies in Special Relativity

Relativistic thermodynamics is generalized to accommodate four dimensional rotation in a flat spacetime. An extended body can be in equilibrium when its each element moves along a Killing flow. There are three types of basic Killing flows in a flat spacetime, each of which corresponds to translational motion, spatial rotation, and constant linear acceleration; spatial rotation and constant linear acceleration are regarded as four dimensional rotation. Translational motion has been mainly investigated in the past literature of relativistic thermodynamics. Thermodynamics of the other two is derived in the present paper.Comment: 8 pages, no figur

Equilibrium of a boson gas in curved spacetime coordinates

Planck distribution in a Rindler spacetime has been calculated as an example of boson gas equilibrium under acceleration/gravitation. It is known that local temperatures of a matter in acceleration/gravitation are not uniform since energy (=mass) is subject to its effect. This causes difficulty in calculating a boson gas equilibrium since bosons are waves spread over the cavity and not localized. A global temperature is introduced, which is based on the conserved quantities resulting from the Killing flow, to overcome this difficulty in the present paper; the Planck distribution is successfully obtained