macrostate
A macrostate is a set of macroscopic properties that describe a physical system, specified by variables such as temperature, pressure, volume, energy, particle number, magnetization, and composition. It captures the large-scale behavior without detailing the exact microscopic configuration. A single macrostate can be realized by many different microscopic configurations, or microstates, that are consistent with the same macroscopic description.
The multiplicity Ω of a macrostate is the number of microstates corresponding to it. In statistical mechanics,
In a system with fixed energy, volume, and particle number, the equilibrium macrostate is the one with
Practical examples include a gas in a container, where the macrostate is defined by energy, volume, and