Pauli X, Y, Z measurement instructions

qiskit/circuit/__init__.py

@@ -286,7 +286,7 @@
 from .operation import Operation
 from .barrier import Barrier
 from .delay import Delay
-from .measure import Measure
+from .measure import Measure, MeasureX, MeasureY, MeasureZ
 from .reset import Reset
 from .parameter import Parameter
 from .parametervector import ParameterVector

qiskit/circuit/library/__init__.py

@@ -136,6 +136,9 @@
    :toctree: ../stubs/
 
    Measure
+   MeasureX
+   MeasureY
+   MeasureZ
    Reset
 
 Generalized Gates
@@ -471,7 +474,7 @@
 from .standard_gates import *
 from .templates import *
 from ..barrier import Barrier
-from ..measure import Measure
+from ..measure import Measure, MeasureX, MeasureY, MeasureZ
 from ..reset import Reset
 
 

qiskit/circuit/library/standard_gates/__init__.py

@@ -109,7 +109,7 @@ def get_standard_gate_name_mapping():
     """Return a dictionary mapping the name of standard gates and instructions to an object for
     that name."""
     from qiskit.circuit.parameter import Parameter
-    from qiskit.circuit.measure import Measure
+    from qiskit.circuit.measure import Measure, MeasureX, MeasureY, MeasureZ
     from qiskit.circuit.delay import Delay
     from qiskit.circuit.reset import Reset
 
@@ -169,6 +169,9 @@ def get_standard_gate_name_mapping():
         ZGate(),
         Delay(Parameter("t")),
         Measure(),
+        MeasureX(),
+        MeasureY(),
+        MeasureZ(),
     ]
     name_mapping = {gate.name: gate for gate in gates}
     return name_mapping

qiskit/circuit/measure.py

@@ -14,15 +14,21 @@
 Quantum measurement in the computational basis.
 """
 
+from __future__ import annotations
+
 import warnings
 
 from qiskit.circuit.instruction import Instruction
 from qiskit.circuit.exceptions import CircuitError
 
 
+# Measure class kept for backwards compatibility, and repurposed
+# as a common parent class for all measurement instructions.
 class Measure(Instruction):
     """Quantum measurement in the computational basis."""
 
+    basis: str | None = None
+
     def __init__(self):
         """Create new measurement instruction."""
         super().__init__("measure", 1, 1, [])
@@ -41,6 +47,71 @@ def broadcast_arguments(self, qargs, cargs):
             raise CircuitError("register size error")
 
 
+class MeasureX(Measure):
+    """Quantum measurement in the X basis."""
+
+    basis: str | None = "X"
+
+    def __init__(self):
+        """Create new X measurement instruction."""
+        # pylint: disable=bad-super-call
+        super(Measure, self).__init__("measure_x", 1, 1, [])
+
+    def _define(self):
+        # pylint: disable=cyclic-import
+        from qiskit.circuit.quantumcircuit import QuantumCircuit
+
+        qc = QuantumCircuit(1, 1)
+        qc.h(0)
+        qc.measure_z(0, 0)
+        qc.h(0)
+
+        self.definition = qc
+
+
+class MeasureY(Measure):
+    """Quantum measurement in the Y basis."""
+
+    basis: str | None = "Y"
+
+    def __init__(self):
+        """Create new Y measurement instruction."""
+        # pylint: disable=bad-super-call
+        super(Measure, self).__init__("measure_y", 1, 1, [])
+
+    def _define(self):
+        # pylint: disable=cyclic-import
+        from qiskit.circuit.quantumcircuit import QuantumCircuit
+
+        qc = QuantumCircuit(1, 1)
+        qc.sdg(0)
+        qc.measure_x(0, 0)
+        qc.s(0)
+
+        self.definition = qc
+
+
+class MeasureZ(Measure):
+    """Quantum Z measurement in the Z basis."""
+
+    basis: str | None = "Z"
+
+    def __init__(self):
+        """Create new measurement instruction."""
+        # pylint: disable=bad-super-call
+        super(Measure, self).__init__("measure_z", 1, 1, [])
+
+    def _define(self):
+        # pylint: disable=cyclic-import
+        from qiskit.circuit.quantumcircuit import QuantumCircuit
+
+        qc = QuantumCircuit(1, 1)
+        qc.measure(0, 0)
+
+        self.definition = qc
+
+
+# TODO: deprecated ? delete : update
 def measure(circuit, qubit, clbit):
     """Measure a quantum bit into classical bit.
 

qiskit/circuit/quantumcircuit.py

@@ -57,7 +57,7 @@
 from .bit import Bit
 from .quantumcircuitdata import QuantumCircuitData, CircuitInstruction
 from .delay import Delay
-from .measure import Measure
+from .measure import Measure, MeasureX, MeasureY, MeasureZ
 from .reset import Reset
 
 try:
@@ -2259,6 +2259,51 @@ def measure(self, qubit: QubitSpecifier, cbit: ClbitSpecifier) -> InstructionSet
         """
         return self.append(Measure(), [qubit], [cbit])
 
+    def measure_x(self, qubit: QubitSpecifier, cbit: ClbitSpecifier) -> InstructionSet:
+        """Measure quantum bit into classical bit (tuples), in the X basis.
+
+        Args:
+            qubit: qubit to measure.
+            cbit: classical bit to place the measurement in.
+
+        Returns:
+            qiskit.circuit.InstructionSet: handle to the added instructions.
+
+        Raises:
+            CircuitError: if arguments have bad format.
+        """
+        return self.append(MeasureX(), [qubit], [cbit])
+
+    def measure_y(self, qubit: QubitSpecifier, cbit: ClbitSpecifier) -> InstructionSet:
+        """Measure quantum bit into classical bit (tuples), in the Y basis.
+
+        Args:
+            qubit: qubit to measure.
+            cbit: classical bit to place the measurement in.
+
+        Returns:
+            qiskit.circuit.InstructionSet: handle to the added instructions.
+
+        Raises:
+            CircuitError: if arguments have bad format.
+        """
+        return self.append(MeasureY(), [qubit], [cbit])
+
+    def measure_z(self, qubit: QubitSpecifier, cbit: ClbitSpecifier) -> InstructionSet:
+        """Measure quantum bit into classical bit (tuples), in the Z basis.
+
+        Args:
+            qubit: qubit to measure.
+            cbit: classical bit to place the measurement in.
+
+        Returns:
+            qiskit.circuit.InstructionSet: handle to the added instructions.
+
+        Raises:
+            CircuitError: if arguments have bad format.
+        """
+        return self.append(MeasureZ(), [qubit], [cbit])
+
     def measure_active(self, inplace: bool = True) -> Optional["QuantumCircuit"]:
         """Adds measurement to all non-idle qubits. Creates a new ClassicalRegister with
         a size equal to the number of non-idle qubits being measured.

qiskit/dagcircuit/dagdependency.py

@@ -21,9 +21,10 @@
 
 from qiskit.circuit.quantumregister import QuantumRegister, Qubit
 from qiskit.circuit.classicalregister import ClassicalRegister, Clbit
+from qiskit.circuit.commutation_checker import CommutationChecker
+from qiskit.circuit.measure import Measure
 from qiskit.dagcircuit.exceptions import DAGDependencyError
 from qiskit.dagcircuit.dagdepnode import DAGDepNode
-from qiskit.circuit.commutation_checker import CommutationChecker
 
 
 # ToDo: DagDependency needs to be refactored:
@@ -382,8 +383,12 @@ def _create_op_node(self, operation, qargs, cargs):
         Returns:
             DAGDepNode: the newly added node.
         """
-        directives = ["measure"]
-        if not getattr(operation, "_directive", False) and operation.name not in directives:
+        directives = []
+        if (
+            not getattr(operation, "_directive", False)
+            and not isinstance(operation, Measure)
+            and operation.name not in directives
+        ):
             qindices_list = []
             for elem in qargs:
                 qindices_list.append(self.qubits.index(elem))

qiskit/visualization/circuit/matplotlib.py

@@ -199,7 +199,7 @@ def __init__(
         self._calibrations = self._circuit.calibrations
 
         for node in itertools.chain.from_iterable(self._nodes):
-            if node.cargs and node.op.name != "measure":
+            if node.cargs and not isinstance(node.op, Measure):
                 if cregbundle:
                     warn(
                         "Cregbundle set to False since an instruction needs to refer"
@@ -992,6 +992,17 @@ def _measure(self, node):
             linewidth=self._lwidth2,
             zorder=PORDER_GATE,
         )
+        if node.op.basis:
+            self._ax.text(
+                qx - 0.4 * WID,
+                qy + 0.25 * HIG,
+                node.op.basis.upper(),
+                color=self._data[node]["gt"],
+                clip_on=True,
+                zorder=PORDER_TEXT,
+                fontsize=0.5 * self._style["fs"],
+                fontweight="bold",
+            )
         # arrow
         self._line(
             self._data[node]["q_xy"][0],

qiskit/visualization/circuit/qcstyle.py

@@ -261,6 +261,9 @@ def __init__(self):
                 "reset": (colors["black"], colors["white"]),
                 "target": (colors["white"], colors["white"]),
                 "measure": (colors["black"], colors["white"]),
+                "measure_x": (colors["black"], colors["white"]),
+                "measure_y": (colors["black"], colors["white"]),
+                "measure_z": (colors["black"], colors["white"]),
             },
         }
 

qiskit/visualization/circuit/styles/default.json

@@ -197,6 +197,18 @@
         "measure": [
             "#000000",
             "#FFFFFF"
+        ],
+        "measure_x": [
+            "#000000",
+            "#FFFFFF"
+        ],
+        "measure_y": [
+            "#000000",
+            "#FFFFFF"
+        ],
+        "measure_z": [
+            "#000000",
+            "#FFFFFF"
         ]
     }
 }

qiskit/visualization/circuit/text.py

@@ -210,12 +210,17 @@ class MeasureFrom(BoxOnQuWire):
         bot: └╥┘    └╥┘
     """
 
-    def __init__(self):
+    def __init__(self, basis=None):
         super().__init__()
         self.top_format = self.mid_format = self.bot_format = "%s"
-        self.top_connect = "┌─┐"
-        self.mid_content = "┤M├"
-        self.bot_connect = "└╥┘"
+        if basis:
+            self.top_connect = "┌───┐"
+            self.mid_content = "┤M_{}├".format(basis.lower())
+            self.bot_connect = "└─╥─┘"
+        else:
+            self.top_connect = "┌─┐"
+            self.mid_content = "┤M├"
+            self.bot_connect = "└╥┘"
 
         self.top_pad = self.bot_pad = " "
         self._mid_padding = "─"
@@ -682,7 +687,7 @@ def __init__(
         self._wire_map = {}
 
         for node in itertools.chain.from_iterable(self.nodes):
-            if node.cargs and node.op.name != "measure":
+            if node.cargs and not isinstance(node.op, Measure):
                 if cregbundle:
                     warn(
                         "Cregbundle set to False since an instruction needs to refer"
@@ -1073,7 +1078,7 @@ def add_connected_gate(node, gates, layer, current_cons):
                     current_cons.append((actual_index, gate))
 
         if isinstance(op, Measure):
-            gate = MeasureFrom()
+            gate = MeasureFrom(op.basis)
             layer.set_qubit(node.qargs[0], gate)
             register, _, reg_index = get_bit_reg_index(self._circuit, node.cargs[0])
             if self.cregbundle and register is not None: