update docs

Qiskit · May 19, 2023 · e264806 · e264806
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commit e264806
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Showing 3 changed files with 15 additions and 10 deletions.
diff --git a/qiskit_aer/noise/device/models.py b/qiskit_aer/noise/device/models.py
@@ -107,11 +107,12 @@ def basic_device_gate_errors(
         properties (BackendProperties): device backend properties.
         gate_error (bool): Include depolarizing gate errors (Default: True).
         thermal_relaxation (Bool): Include thermal relaxation errors (Default: True).
-                If ``T1`` or ``T2`` value is not supplied via ``target`` (i.e. None) for some qubits,
-                no thermal relaxation errors are added to the qubits even if this flag is True.
-                If ``frequency`` is not defined (i.e. None) for a qubit, no excitation is considered
-                in the thermal relaxation error on the qubit even if non-zero ``temperature``
-                is supplied.
+                If no ``t1`` and ``t2`` values are provided (i.e. None) in ``target`` for a qubit,
+                an identity ``QuantumError` (i.e. effectively no thermal relaxation error)
+                will be added to the qubit even if this flag is set to True.
+                If no ``frequency`` is not defined (i.e. None) in ``target`` for a qubit,
+                no excitation is considered in the thermal relaxation error on the qubit
+                even with non-zero ``temperature``.
         gate_lengths (list): Override device gate times with custom
                              values. If None use gate times from
                              backend properties. (Default: None).

diff --git a/qiskit_aer/noise/noise_model.py b/qiskit_aer/noise/noise_model.py
@@ -474,10 +474,14 @@ def from_backend_properties(
         Args:
             backend_properties (BackendProperties): The property of backend.
             gate_error (Bool): Include depolarizing gate errors (Default: True).
-            readout_error (Bool): Include readout errors in model
-                                  (Default: True).
-            thermal_relaxation (Bool): Include thermal relaxation errors
-                                       (Default: True).
+            readout_error (Bool): Include readout errors in model (Default: True).
+            thermal_relaxation (Bool): Include thermal relaxation errors (Default: True).
+                If no ``t1`` and ``t2`` values are provided (i.e. None) in ``target`` for a qubit,
+                an identity ``QuantumError` (i.e. effectively no thermal relaxation error)
+                will be added to the qubit even if this flag is set to True.
+                If no ``frequency`` is not defined (i.e. None) in ``target`` for a qubit,
+                no excitation is considered in the thermal relaxation error on the qubit
+                even with non-zero ``temperature``.
             temperature (double): qubit temperature in milli-Kelvin (mK) for
                                   thermal relaxation errors (Default: 0).
             gate_lengths (Optional[list]): Custom gate times for thermal relaxation errors.

diff --git a/releasenotes/notes/fix-none-handling-in-noise-model-34fcc9a3e3cbdf6f.yaml b/releasenotes/notes/fix-none-handling-in-noise-model-34fcc9a3e3cbdf6f.yaml
@@ -4,7 +4,7 @@ fixes:
     Fixed a bug in :meth:`~.NoiseModel.from_backend` that raised an error when
     the backend has no T1 and T2 values (i.e. None) for a qubit in its qubit properties.
     This commit updates :meth:`NoiseModel.from_backend` and :func:`basic_device_gate_errors`
-    so that they add an identity ``QuantumError` (i.e. no thermal relaxation error)
+    so that they add an identity ``QuantumError`` (i.e. effectively no thermal relaxation error)
     to a qubit with no T1 and T2 values for all gates acting on qubits including the qubit.
     Fixed `#1779 <https://github.com/Qiskit/qiskit-aer/issues/1779>`__
     and `#1815 <https://github.com/Qiskit/qiskit-aer/issues/1815>`__.