A pedagogical introduction to thermodynamic systems with zero chemical potential

Abstract We explore the pedagogically interesting problem in thermal physics, the thermodynamic consequences of having fixed chemical potential μ equal to zero. We will show that the zero chemical potential gas (ZCPG) equation of state (EOS) is directly defined via its internal energy density u = u ( T ), which in this case has to be a function of temperature only. The main aim of this article is to unify gases with μ = 0 under one general framework of the ZCPG EOS which is better accessible to undergraduate students. We define properties of a ZCPG and then focus on an interesting subset of ZCPGs due to its simplicity, and in this context, we utilize electromagnetic radiation in equilibrium with cavity walls as specific pedagogical examples of a ZCPG.