2D Ising Model Average Number of Domain Walls

  • Context: Undergrad 
  • Thread starter Thread starter thatboi
  • Start date Start date
  • Tags Tags
    Classical Domain
Click For Summary
SUMMARY

The discussion centers on the calculation of the average number of domain walls per site in a 2D Ising model on a square lattice with N sites and no external field. The average internal energy per site at criticality is established as u = -√2, with the coupling constant J set to 1. The calculation reveals that the average number of domain walls per site can be expressed as n_walls/N = (2 - √2)/2, derived from the relationship between the ground state energy and the energy at criticality.

PREREQUISITES
  • Understanding of the Ising model in statistical mechanics
  • Familiarity with concepts of domain walls and their energy contributions
  • Knowledge of critical phenomena and phase transitions
  • Basic algebra for solving equations related to energy states
NEXT STEPS
  • Study the derivation of the Ising model's average internal energy per site
  • Explore the implications of domain walls in phase transitions
  • Investigate the role of external fields in the Ising model
  • Learn about numerical simulations of the Ising model using Monte Carlo methods
USEFUL FOR

Physicists, particularly those specializing in statistical mechanics and condensed matter physics, as well as students and researchers interested in phase transitions and critical phenomena.

thatboi
Messages
130
Reaction score
20
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?
 

Similar threads

  • · Replies 0 ·
Replies
0
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 85 ·
3
Replies
85
Views
9K
Replies
49
Views
3K
  • · Replies 21 ·
Replies
21
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K