Ising model
An Ising model is a simple model used in statistical mechanics.
The Ising model tries to imitate behavior in which individual elements (e.g., atoms, animals, protein folds, biological membrane, social behavior, etc.) modify their behavior so as to conform to the behavior of other individuals in their vicinity.
Brief History
The Ising model was proposed in the 1924 doctoral thesis of Ernst Ising, a student of W. Lenz. Ising tried to explain certain empirically observed facts about ferromagnetic materials using a model of proposed by Lenz (1920).
It was referred to in Heisenberg's (1928) paper which used the exchange mechanism to describe ferromagnetism.
The name became well-established with the publication of a paper by Peierls (1936), which gave a non-rigorous proof that spontaneous magnetization must exist.
A breakthrough occurred when it was shown that a matrix formulation of the model allows the partition function to be related to the largest eigenvalue of the matrix (Kramers and Wannier 1941, Montroll 1941, 1942, Kubo 1943). Kramers and Wannier (1941) calculated the Curie temperature using a two-dimensional Ising model.
A complete analytic solution was subsequently given by Onsager (1944).
Applications
Recent
The Ising model has more recently been used to model phase separation in binary alloys and spin glasses.
Biology
The Ising model represents neural networks, flocking birds, or beating heart cells.
Sociology
Religion and peer pressure are very good examples of this