Mesostate

[…] the liquid to the solid state via first-order phase transformations, which must be preceded by a breakdown of the structure of the mesostate—an intermediate state of the alum in its transition from the solution to the crystaline phase.

Many substances can be in a state between crystallized and liquid. This means that the molecules have more freedom of motion than in the solid state but not as much as in a liquid, a condition called mesostate.

If the manipulation is slow enough, and the driving connects different mesostates, then jumps between states in the same mesostate satisfy the detailed balance condition.

Even though we said the mesostates x are relatively stable, after a very long time they will also eventually thermalize (unless we additionally protect them).

For systems with metastable conformations, a trajectory initiated in one mesostate spends a (potentially) long time sampling microstates in that mesostate before overcoming the energy barrier to sample the other mesostate, and due to the timescale separateion between the simulation timestep and reaction transitions, it becomes impractical to compute free energies via a brute-force approach.

In operational urban simulation models, virtually no attempt is made to simulate at the level of microstates, i.e., individual behavior. Most of the models operate at the mesostate and/or macrostate level.

Given a microstate description of a system, only one mesostate is possible; and given a mesostate description, only one macrostate is possible: in both cases the higher level description can be found by simple summation ( see Equations 8,3,4) .

For instance, in the first mesostate, the five female voters can only be allocated one way: all voted for a party other than the PDS. Each one of the four males, however, could have voted for a non-PDS party. Therefore, there are a total of four microstates associated with the first mesostate.