Statistical Physics

As a system is de ned by the collection of a large number of particles, so the “ensembles” can be de ned as a collection of a number macroscopically identical but essentially independent systems. Here the term macroscopically identical means, as, each of the systems constituting an ensemble satis es the same macroscopic conditions, like Volume, Energy, Pressure, Temperature and Total number of particles etc. Here again, the term essentially independent means the system (in the ensemble) being mutually non-interacting to others, i.e., the systems di er in microscopic conditions like parity, symmetry, quantum states etc.