The relation between relativistic and non-relativistic continuum thermodynamics

Abstract

We consider the relativistic theory of irreversible processes with the aim to answer the following questions: (1) Under which conditions is this theory a relativistic generalization of the non-relativistic theory of irreversible processes (in particular, this implies to ask for the conditions under which the first law of thermodynamics can be recovered from the relativistic conservation law of total energy), and (2) how do the relativistic corrections look like? To this end, we perform a low-energy approximation for the balance equations underlying the theory, i.e., for the balances of the particle number, the energy-momentum and the entropy. It is shown that, going up to the 3rd order in the expansion series of the balances, the non-relativistic theory can be derived when one assumes that the 4-current of the particle flow is purely convective and the product of the 3-dimensional acceleration and velocity is equal to zero. Afterwards, the higher-order terms are discussed. Since our discussion mainly makes use of those balance equations that lie on the basis of most versions of continuum thermodynamics, the results do not only refer to early TIP presented by Eckart (Phys Rev 58:919, 1940) and Landau and Lifshitz (Fluid mechanics. Pergamon Press, Oxford, 1940), but also to its extended and/or general-relativistic versions.