Package structure#

The directory structure of the package appears below.

Code Block 1 Package structure of Qhronology#

qhronology
├──quantum
│  ├──circuits.py
│  ├──gates.py
│  ├──prescriptions.py
│  └──states.py
├──mechanics
│  ├──matrices.py
│  ├──operations.py
│  └──quantities.py
└──utilities
   ├──classification.py
   ├──diagrams.py
   ├──helpers.py
   ├──objects.py
   └──symbolics.py

It consists of three subpackages:

quantum: most of the package’s underlying mathematical framework and its user-facing classes.
mechanics: core logic for creating fundamental quantum objects, performing operations on them, and computing various quantum-mechanical scalar quantities.
utilities: a collection of modules containing various functionality intended for internal-use only, including the visualization engine, the core QuantumObject class, and assorted helper functions.

In this documentation, we focus solely on the quantum and mechanics subpackages, with the former containing all of the classes intended to be user-facing. These are summarized in the following subsections.

`quantum` subpackage#

The quantum subpackage contains most of Qhronology’s underlying mathematical framework and its user-facing classes.

Table 1 Overview of Qhronology’s `quantum` subpackage.#
Module	Contents	Objects
`states.py`	Classes for the creation of quantum states.	Main class: `QuantumState` Subclasses: `VectorState` `MatrixState` `PureState` `MixedState`
`gates.py`	Classes for the creation of quantum gates.	Main class: `QuantumGate` Subclasses: `Pauli` `GellMann` `Rotation` `Phase` `Diagonal` `Swap` `Summation` `Not` `Hadamard` `Fourier` `Measurement` Combinations: `GateInterleave` `GateStack`
`circuits.py`	A class for the creation of quantum circuits.	Class: `QuantumCircuit`
`prescriptions.py`	A class for the creation of quantum circuits containing closed timelike curves. Classes and functions implementing quantum prescriptions of time travel.	Main class: `QuantumCTC` Subclasses: `DCTC` `PCTC`

`mechanics` subpackage#

The mechanics subpackage contains Qhronology’s core logic for creating fundamental quantum objects, performing operations on them, and computing scalar quantities.

Table 2 Overview of Qhronology’s `mechanics` subpackage.#
Module	Contents	Objects
`matrices.py`	Core functions for creating quantum vectors and matrices.	Functions: `vector_basis()` `ket()` `bra()` `quantum_state()` `encode()` `decode_slow()` `decode()` `decode_fast()` `decode_multiple()`
`operations.py`	Functions for performing quantum operations on matrices. A mixin for endowing compatible classes with the ability to perform these operations.	Functions: `densify()` `columnify()` `dagger()` `simplify()` `rewrite()` `apply()` `normalize()` `coefficient()` `partial_trace()` `measure()` `postselect()` Mixin: `OperationsMixin`
`quantities.py`	Functions for computing quantum quantities from matrices. A mixin for endowing compatible classes with the ability to calculate these quantities.	Functions: `trace()` `purity()` `distance()` `fidelity()` `entropy()` `mutual()` Mixin: `QuantitiesMixin`

Package structure#

quantum subpackage#

mechanics subpackage#

`quantum` subpackage#

`mechanics` subpackage#