added fix for efficient_su2

Qiskit · Dec 3, 2024 · ea6fa73 · ea6fa73
1 parent 8e2aaad
commit ea6fa73
Show file tree

Hide file tree

Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/qiskit/circuit/library/n_local/efficient_su2.py b/qiskit/circuit/library/n_local/efficient_su2.py
@@ -114,10 +114,13 @@ def efficient_su2(
     if su2_gates is None:
         su2_gates = ["ry", "rz"]
 
+    # Set entanglement_blocks to None when num_qubits == 1
+    entanglement_blocks = ['cx'] if num_qubits > 1 else []
+
     return n_local(
         num_qubits,
         su2_gates,
-        ["cx"],
+        entanglement_blocks,
         entanglement,
         reps,
         insert_barriers,

diff --git a/test/python/circuit/library/test_nlocal.py b/test/python/circuit/library/test_nlocal.py
@@ -790,6 +790,12 @@ def test_efficient_su2(self):
         expected = n_local(4, ["ry", "rz"], "cx", "reverse_linear", reps=3)
         self.assertEqual(expected.assign_parameters(circuit.parameters), circuit)
 
+    def test_efficient_su2_numqubits_equal1(self):
+        """Test the efficient SU(2) circuit."""
+        circuit = efficient_su2(1)
+        expected = n_local(1, ["ry", "rz"], [], "reverse_linear", reps=3)
+        self.assertEqual(expected.assign_parameters(circuit.parameters), circuit)
+
     @data("fsim", "iswap")
     def test_excitation_preserving(self, mode):
         """Test the excitation preserving circuit."""