This applet demonstrates the 2 dimensional Ising model with no external field on a 20 by 20 square lattice. The spins are altered according to the Metropolis Monte Carlo method. For the purposes of the Boltzmann distribution, k is unity. The coupling constant between nearest neighbor spins (J) is -1, reflecting ferromagnetic coupling.
The temperature of the simulation can be altered by clicking on the "TEMP+" box to increase the temperature in units of 0.1, and clicking on "TEMP-" to decrease the temperature by the same amount.
"Up" spins (spin = 1/2) are represented by red circles, and "Down" spins (spin = -1/2) are represnted y blue circles.
After 5,000 cycles, the applet begins collecting data so as to evaluate the heat capacity and magnetic susceptibility. Both the heat capacity and magnetic susceptibility have a maximum at the critical temperature.
© 2003-2011 by Lawrence T. Sein. All rights reserved.
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