Configurations
To better understand what is meant with a configuration,
consider first the case of the one-dimensional Ising model
with
B=0.
In general, a given configuration of
N spins in one
dimension may look like
↑↑↑…↑↓↑…↑↓123…i−1ii+1…N−1N
In order to illustrate these features
let us further specialize to
just two spins.
With two spins, since each spin takes two values only,
we have 22=4 possible arrangements of the two spins.
These four possibilities are
1=↑↑2=↑↓3=↓↑4=↓↓