clock_model

src/models/.ipynb_checkpoints/ising-checkpoint.jl

@@ -0,0 +1,76 @@
+const Ising_βc = log(1.0 + sqrt(2)) / 2.0
+Potts_βc(q) = log(1.0 + sqrt(q))
+
+const f_onsager::BigFloat = -2.10965114460820745966777928351108478082549327543540531781696107967700291143188081390114126499095041781
+
+function classical_ising(β::Number; h=0)
+    function σ(i::Int64)
+        return 2i - 3
+    end
+
+    T_array = [exp(β * (σ(i)σ(j) + σ(j)σ(k) + σ(k)σ(l) + σ(l)σ(i)) +
+                   h / 2 * β * (σ(i) + σ(j) + σ(k) + σ(l)))
+               for i in 1:2, j in 1:2, k in 1:2, l in 1:2]
+
+    T = TensorMap(T_array, ℝ^2 ⊗ ℝ^2 ← ℝ^2 ⊗ ℝ^2)
+
+    return T
+end
+
+function classical_ising_symmetric(β)
+    V = Vect[Z2Irrep](0 => 1, 1 => 1)
+    Ising = zeros(2, 2, 2, 2)
+    c = cosh(β)
+    s = sinh(β)
+    for i in 1:2
+        for j in 1:2
+            for k in 1:2
+                for l in 1:2
+                    if (i + j + k + l) == 4
+                        Ising[i, j, k, l] = 2 * c * c
+                    elseif (i + j + k + l) == 6
+                        Ising[i, j, k, l] = 2 * c * s
+                    elseif (i + j + k + l) == 8
+                        Ising[i, j, k, l] = 2 * s * s
+                    end
+                end
+            end
+        end
+    end
+    return TensorMap(Ising, V ⊗ V ← V ⊗ V)
+end
+
+function classical_Potts(q::Int64, β::Float64)
+    V = ℂ^q
+    A_potts = TensorMap(zeros, V ⊗ V ← V ⊗ V)
+
+    for i in 1:q
+        for j in 1:q
+            for k in 1:q
+                for l in 1:q
+                    E = -(Int(i == j) + Int(j == k) + Int(k == l) + Int(l == i))
+                    A_potts[i, j, k, l] = exp(-β * E)
+                end
+            end
+        end
+    end
+    return A_potts
+end
+
+function classical_Clock(q::Int64, β::Float64)
+    V = ℂ^q
+    A_clock = TensorMap(zeros, V ⊗ V ← V ⊗ V)
+    clock(i,j) = -cos(2π/q*(i-j))
+
+    for i in 1:q
+        for j in 1:q
+            for k in 1:q
+                for l in 1:q
+                    E = clock(i,j)+clock(j,k)+clock(k,l)+clock(l,i)
+                    A_clock[i, j, k, l] = exp(-β * E)
+                end
+            end
+        end
+    end
+    return A_clock
+end

src/models/ising.jl

@@ -56,3 +56,21 @@ function classical_Potts(q::Int64, β::Float64)
     end
     return A_potts
 end
+
+function classical_Clock(q::Int64, β::Float64)
+    V = ℂ^q
+    A_clock = TensorMap(zeros, V ⊗ V ← V ⊗ V)
+    clock(i,j) = -cos(2π/q*(i-j))
+
+    for i in 1:q
+        for j in 1:q
+            for k in 1:q
+                for l in 1:q
+                    E = clock(i,j)+clock(j,k)+clock(k,l)+clock(l,i)
+                    A_clock[i, j, k, l] = exp(-β * E)
+                end
+            end
+        end
+    end
+    return A_clock
+end