[Stretch] Add stretch variable support to QuantumCircuit.

crates/circuit/src/duration.rs

@@ -0,0 +1,36 @@
+// This code is part of Qiskit.
+//
+// (C) Copyright IBM 2025
+//
+// This code is licensed under the Apache License, Version 2.0. You may
+// obtain a copy of this license in the LICENSE.txt file in the root directory
+// of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+//
+// Any modifications or derivative works of this code must retain this
+// copyright notice, and modified files need to carry a notice indicating
+// that they have been altered from the originals.
+
+use pyo3::prelude::*;
+
+#[pyclass(eq, module = "qiskit._accelerate.circuit")]
+#[derive(PartialEq, Clone, Copy, Debug)]
+#[allow(non_camel_case_types)]
+pub enum Duration {
+    dt(u64),
+    ns(f64),
+    us(f64),
+    ms(f64),
+    s(f64),
+}
+
+impl Duration {
+    fn __repr__(&self) -> String {
+        match self {
+            Duration::ns(t) => format!("Duration.ns({})", t),
+            Duration::us(t) => format!("Duration.us({})", t),
+            Duration::ms(t) => format!("Duration.ms({})", t),
+            Duration::s(t) => format!("Duration.s({})", t),
+            Duration::dt(t) => format!("Duration.dt({})", t),
+        }
+    }
+}

crates/circuit/src/lib.rs

@@ -17,6 +17,7 @@ pub mod converters;
 pub mod dag_circuit;
 pub mod dag_node;
 mod dot_utils;
+pub mod duration;
 pub mod error;
 pub mod gate_matrix;
 pub mod imports;
@@ -157,6 +158,7 @@ macro_rules! impl_intopyobject_for_copy_pyclass {
 }
 
 pub fn circuit(m: &Bound<PyModule>) -> PyResult<()> {
+    m.add_class::<duration::Duration>()?;
     m.add_class::<circuit_data::CircuitData>()?;
     m.add_class::<circuit_instruction::CircuitInstruction>()?;
     m.add_class::<dag_circuit::DAGCircuit>()?;

qiskit/circuit/__init__.py

@@ -1282,6 +1282,8 @@ def __array__(self, dtype=None, copy=None):
         \end{pmatrix}
 """
 
+from qiskit._accelerate.circuit import Duration  # pylint: disable=unused-import
+
 from .exceptions import CircuitError
 from . import _utils
 from .quantumcircuit import QuantumCircuit

qiskit/circuit/classical/expr/__init__.py

@@ -210,6 +210,10 @@
     "greater",
     "greater_equal",
     "index",
+    "add",
+    "sub",
+    "mul",
+    "div",
     "lift_legacy_condition",
 ]
 
@@ -234,5 +238,9 @@
     shift_left,
     shift_right,
     index,
+    add,
+    sub,
+    mul,
+    div,
     lift_legacy_condition,
 )