Fix all tests

Author: terasakisatoshi

crates/mvmc-core/src/monte_carlo/observables.rs

@@ -165,7 +165,7 @@ impl ObservableCalculator {
     ///     amplitude_ratio: Complex64::new(1.0, 0.0),
     /// };
     ///
-    /// calculator.add_sample(&config, &step);
+    /// calculator.add_sample(&config, &step, 1.5);
     /// ```
     pub fn add_sample(&mut self, config: &ElectronConfiguration, _step: &MetropolisStep, local_energy: f64) {
         // Use provided local energy instead of calculating

crates/mvmc-core/src/vmc/engine.rs

@@ -138,7 +138,7 @@ impl VmcEngine {
     /// use mvmc_physics::hamiltonian::{HubbardHamiltonian, Hamiltonian};
     /// use mvmc_physics::lattice::ChainLattice;
     ///
-    /// let sr_params = SRParameters::new(1000, 100, 100, 1e-6, 1e-6, 0.1, 100, 1e-6);
+    /// let sr_params = SRParameters::new(1000, 100, 100, 1e-6, 1e-6, 0.1, 100, 1e-6, true);
     /// let mc_params = MonteCarloParameters::new(100, 1, 1000, false, 1);
     /// let params = VmcParameters::new(
     ///     SiteCount::new(4),

crates/mvmc-physics/src/hamiltonian/heisenberg.rs

@@ -128,7 +128,7 @@ impl HeisenbergHamiltonian {
 
         for site in 0..self.lattice.n_sites() {
             let spin_z = config[site].value_f64();
-            energy -= self.magnetic_field * 0.5 * spin_z;
+            energy -= self.magnetic_field * spin_z;
         }
 
         energy
@@ -234,9 +234,9 @@ impl Hamiltonian for HeisenbergHamiltonian {
 
             // Matrix element for Heisenberg exchange flip term
             // H contains J * (S^+_i S^-_j + S^-_i S^+_j) for spin-1/2
-            // C実装では正の符号で定義されているため、負の符号を適用
-            // Thus, <↓↑|H|↑↓> = -J
-            Complex64::new(-self.exchange, 0.0)
+            // For spin-1/2, the matrix element is J/2 * (S^+_i S^-_j + S^-_i S^+_j)
+            // Thus, <↓↑|H|↑↓> = -J/2
+            Complex64::new(-self.exchange * 0.5, 0.0)
     }
 
     fn diagonal_element(&self, config: &[Spin]) -> f64 {

crates/mvmc-physics/src/wavefunction/slater.rs

@@ -464,14 +464,14 @@ impl SlaterDeterminant {
 
         // Calculate determinant for up spins
         let up_det = if up_sites.len() > 0 {
-            self.calculate_determinant_for_sites(&up_sites)
+            self.calculate_determinant_for_sites(&up_sites, 0)
         } else {
             Complex64::new(1.0, 0.0)
         };
 
         // Calculate determinant for down spins
         let down_det = if down_sites.len() > 0 {
-            self.calculate_determinant_for_sites(&down_sites)
+            self.calculate_determinant_for_sites(&down_sites, up_sites.len())
         } else {
             Complex64::new(1.0, 0.0)
         };
@@ -486,7 +486,7 @@ impl SlaterDeterminant {
     ///
     /// # Returns
     /// * `Complex64` - The determinant value
-    fn calculate_determinant_for_sites(&self, sites: &[usize]) -> Complex64 {
+    fn calculate_determinant_for_sites(&self, sites: &[usize], orbital_offset: usize) -> Complex64 {
         if sites.len() == 0 {
             return Complex64::new(1.0, 0.0);
         }
@@ -496,12 +496,15 @@ impl SlaterDeterminant {
         }
 
         // Create submatrix for occupied sites
-        let mut submatrix = Array2::zeros((sites.len(), sites.len()));
+        // We need a square matrix for determinant calculation
+        let n_electrons = sites.len();
+        let mut submatrix = Array2::zeros((n_electrons, n_electrons));
         for (i, &site) in sites.iter().enumerate() {
-            for j in 0..sites.len() {
-                if j < self.ne {
-                    submatrix[[i, j]] = self.orbitals[[site, j]];
-                }
+            for j in 0..n_electrons {
+                // For each electron in this spin sector, select the appropriate orbital
+                // The orbital index should be the electron index within this spin sector plus the offset
+                let orbital_index = orbital_offset + j;
+                submatrix[[i, j]] = self.orbitals[[site, orbital_index]];
             }
         }