Statistical Mechanics: A Journey into the Microscopic World

The microstate of a system is completely determined by the positions and momenta of its constituent particles.

The macrostate of a system is completely determined by its thermodynamic variables, such as temperature, pressure, and volume.

The entropy of a system is a measure of the number of microstates that are consistent with the macrostate.

The probability of a microstate is proportional to the Boltzmann factor, which is given by the exponential of the negative of the microstate's energy.