Abstract
A class of systems of noninteracting quantum-mechanical particles is defined, so that it is often justifiable to approximate a given system of particles as a system of class . A "limit " is defined as the limiting case which arises of the number of particles and the volume of the system are both allowed to tend to infinity so as to keep the ratio a finite and nonzero constant. It is shown that if one wishes to calculate the mean value of an extensive variable, as averaged over a canonical or over a grand canonical ensemble, for a system of class in the limit , one can apply the continuous spectrum approximation directly to the particle quantum states (excepting, possibly, the states which belong to the lowest energy level) without using a limiting process.
- Received 14 December 1953
DOI:https://doi.org/10.1103/PhysRev.94.469
©1954 American Physical Society