Fix converting Rxx and similar Qiskit gates (#2579)

AUTHORS

@@ -59,3 +59,4 @@ Vladimir Kozhukalov
 Francesc Sabater
 Emiliano Godinez
 Tommy Nguyen
+Duong H. D. Tran

mitiq/interface/mitiq_qiskit/conversions.py

@@ -249,14 +249,17 @@ def from_qiskit(circuit: qiskit.QuantumCircuit) -> cirq.Circuit:
     Returns:
         Mitiq circuit representation equivalent to the input Qiskit circuit.
     """
+
     try:
         mitiq_circuit = from_qasm(qasm2.dumps(circuit))
     except QasmException:
         # Try to decompose circuit before running
         # This is necessary for converting qiskit circuits with
         # custom packaged gates, e.g., QFT gates
-        circuit = circuit.decompose()
+        GATES_TO_DECOMPOSE = ["rxx", "rzz", "rzx", "ryy", "QFT"]
+        circuit = circuit.decompose(gates_to_decompose=GATES_TO_DECOMPOSE)
         mitiq_circuit = from_qasm(qasm2.dumps(circuit))
+
     return mitiq_circuit
 
 

mitiq/interface/mitiq_qiskit/tests/test_conversions_qiskit.py

@@ -476,3 +476,11 @@ def test_remove_identity_from_idle_with_multiple_registers():
     input_multi, input_single = _multi_reg_circuits()
     assert circuit_multi_reg == input_multi
     assert circuit_single_reg == input_single
+
+
+def test_convert_to_mitiq_with_rx_and_rzz():
+    """Tests that convert_to_mitiq works with RX and RZZ gates."""
+    test_qc = qiskit.QuantumCircuit(2)
+    test_qc.rx(0.1, 0)
+    test_qc.rzz(0.1, 0, 1)
+    assert convert_to_mitiq(test_qc)