2D Ising Model Average Number of Domain Walls

In summary, the study of the 2D Ising model focuses on understanding the average number of domain walls that form in a system of spins on a lattice. Domain walls are boundaries separating regions of different spin orientations, and their average number is influenced by temperature, interactions between spins, and the system's overall configuration. The analysis employs statistical mechanics and computational methods to derive insights into phase transitions and critical phenomena, highlighting the significance of domain walls in determining the properties of the system.
  • #1
thatboi
133
18
Hi all,
I'm trying to see if my question/logic makes sense. Suppose I have a classical Ising model on a 2-D Square lattice with ##N## sites and 0 external field. There is an exact formula for the average internal energy per site, and at criticality it turns out to be ##u = -\sqrt{2}## where I have set the coupling constant ##J=1##. From here, I'd like to know if it is possible to find the average number of domain walls per site. I know each domain wall contributes energy ##2##. Now suppose the system is in its ground state (say all spin-up). Then the ground state energy is ##-2N##. I want to put in domain walls until the system energy increases to ##-\sqrt{2}N##, so we just need to solve ##-2N + 2n_{\text{walls}} = -\sqrt{2}N## and I get ##\frac{n_{\text{walls}}}{N} = \frac{2-\sqrt{2}}{2}##. Does this make sense?
 
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