The one-dimensional Ising model with nearest neighbor interaction, no external field and a constant coupling constant \( J \) is given by $$ \begin{align} H = -J \sum_{k}^L s_k s_{k + 1}, \tag{30} \end{align} $$ where \( s_i \in \{-1, 1\} \) and \( s_{N + 1} = s_1 \). The number of spins in the system is determined by \( L \). For the low temperature limit there is no phase transition.
We will look at a system of \( L = 40 \) spins with a coupling constant of \( J = 1 \). To get enough training data we will generate 10000 states with their respective energies.
L = 40
n = int(1e4)
spins = np.random.choice([-1, 1], size=(n, L))
J = 1.0
energies = np.zeros(n)
for i in range(n):
energies[i] = - J * np.dot(spins[i], np.roll(spins[i], 1))