symop.devices.types.measurement

Type aliases for semantic measurement resolution.

This module defines small literal-based type aliases used to describe how a measured device resolves selected subsystems and how its outcomes are reported at the semantic layer.

The goal of these types is to keep measurement planning explicit and representation-independent. A semantic measurement action should be able to state, in a compact and structured way:

• which detector-visible axes are being resolved,

• how outcomes across one or more ports are grouped,

• and what readout family the detector reports.

These aliases do not describe the concrete backend implementation of a measurement. In particular, they do not specify the actual POVM effects, Kraus operators, or state-update rule. Those belong to a lower layer, such as a measurement specification or instrument description.

Overview

A measurement resolution is described along three types:

MeasurementAxis

Describes the physical or semantic axes in which the detector resolves the selected subsystem. Multiple axes can be defined for a single detector.

MeasurementGrouping

Describes how outcomes from multiple logical detector ports are combined.

MeasurementReadout

Describes the family of detector outcomes that should be reported.

These three types are intentionally separated because they answer different questions:

• “axis”: what structure of the subsystem is visible to the detector?

• “grouping”: how are multiple detector channels combined into outcomes?

• “readout”: what kind of classical record is produced?

Measurement axis

MeasurementAxis specifies the detector-visible decomposition of the selected subsystems.

The supported values are:

"path"

Resolve the measurement in terms of detector paths or channels. This is the most common default for ideal path-local detectors. For example, a number detector on one input path typically measures the total photon number associated with the path-visible subsystems.

"mode"

Resolve the measurement with respect to explicitly selected modes. This is a more fine-grained and representation-sensitive option and is typically most useful when the measured modes are already well defined at the semantic level.

"time_bin"

Resolve the measurement in terms of temporal bins or gated detection windows. This is useful for early/late-bin detectors or any measurement whose outcomes depend on arrival-time structure.

"polarization"

Resolve the measurement with respect to polarization subspaces or polarization-resolved detector channels.

Measurement grouping

MeasurementGrouping specifies how outcomes from multiple logical ports are combined.

The supported values are:

"total"

Report outcomes aggregated across all selected ports.

"per_port"

Report outcomes separately for each logical detector port.

"joint_ports"

Report joint outcomes across multiple ports, preserving correlations between them.

Measurement readout

MeasurementReadout specifies the classical outcome family reported by the detector.

The supported values are:

"number"

Exact-number readout, such as 0, 1, 2, …

"threshold"

Threshold or bucket-detector readout, such as "click" or "no-click".

"parity"

Parity readout, for example even versus odd excitation number.

"custom"

A custom readout family defined elsewhere, for example by an explicit POVM or instrument specification. This value indicates that the literal alone is not sufficient to determine the outcome set.

Notes

These aliases are intended for semantic planning and validation. They are small on purpose and should remain stable and easy to inspect.

For arbitrary POVMs or more general instruments, these types should be supplemented by richer measurement-specification objects carrying the explicit outcome model and operator-level data required for execution.

Classes

MeasurementAxisEnum(*values)
MeasurementGrouppingEnum(*values)
MeasurementIntentEnum(*values)
MeasurementReadoutEnum(*values)

class MeasurementAxisEnum(*values)

Bases: StrEnum

MODE = 'mode'

PATH = 'path'

POLARIZATION = 'polarization'

TIME_BIN = 'time_bin'

static _generate_next_value_(name, start, count, last_values)

Return the lower-cased version of the member name.

class MeasurementGrouppingEnum(*values)

Bases: StrEnum

JOINT_PORTS = 'joint_ports'

PER_PORT = 'per_port'

TOTAL = 'total'

static _generate_next_value_(name, start, count, last_values)

Return the lower-cased version of the member name.

class MeasurementIntentEnum(*values)

Bases: StrEnum

DETECT = 'detect'

OBSERVE = 'observe'

POSTSELECT = 'postselect'

static _generate_next_value_(name, start, count, last_values)

Return the lower-cased version of the member name.

class MeasurementReadoutEnum(*values)

Bases: StrEnum

CUSTOM = 'custom'

NUMBER = 'number'

PARITY = 'parity'

THRESHOLD = 'threshold'

static _generate_next_value_(name, start, count, last_values)

Return the lower-cased version of the member name.