goldsmdn / steanecode

MSc Steane Code project

SteaneCode

MSc Steane Code project

For documentation of the SteaneCodeLogicalQubit class please see the automatically produced documentation.

Please see the Pipecleaning repository for the initial work from which the baseline files were copied.

List of workbooks

Workbook Steane Code is a good place to start. It illustrates the main method calls.

The following additional workbooks are included:

Basic tests

• Basic_single_qubit_errors.ipynb : Compares simulation of parallel single-qubit gates to calculation.
• Basic_single_qubit_errors_transpilation.ipynb : Compares simulation of parallel single-qubit gates to calculation for transpiled gates.
• Steane Code single-qubit error sensitivity : Finds sensitivity of simulations to single-qubit errors.
• Basic_two_qubit_errors.ipynb : Compares simulation of parallel two qubit gates to calculation.

Calibration of noise model

• Egan_single_qubit_errors.ipynb : Compares simulation of randomised benchmarking of Clifford gates to Egan’s observations.
• Egan_two_qubit_errors.ipynb : Compare simulation of parallel XX gates to Egan’s experimental observations.
• Bacon_Shor_1.ipynb : Simulation of full Bacon Shor code 1.
• Bacon_Shor_1.ipynb : Simulation of full Bacon Shor code 2.

Steane code encoding

• Steane Code encoding : Check how much noise is introduced by the encoding circuit.
• Steane Code encoding FTb : Test fault tolerance encoding using scheme B from Goto.
• Steane Code encoding FTc : Test fault tolerance encoding using scheme C from Goto.
• Steane Code encoding FTd : Test novel fault tolerance encoding scheme D.
• Steane Code FT encoding : Plots performance of a single-qubit, non fault tolerant encoding and scheme B, C and D.

Steane code error correction

• Steane Code correction no noise : Ensures that when there is no noise any errors introduced on the Steane code are corrected.
• Steane Code correction noise : Assess the noise introduced by error correction.
• Steane Code error detection software decoding with noise : Measures errors before and after error correction, with and without noise.

Steane code decoding

• Steane Code decoding with noise : Assess noise introduced by each the measurement, encoding, detection and decoding stages.
• Steane Code decoding no noise : Ensures that when there is no noise any errors introduced on the Steane code are corrected and are the results are decoded correctly.

Logical operations

• Steane Code logical operation : Sets up a circuit to produce a logical Bell pair.
• Steane Code logical operation test software decoding with noise : Test the decoding software by introducing errors and making sure these get corrected.
• Steane Code logical operation software decoding with noise and without transpilation : Carries out a sensitivity analysis of the performance of a physical and logical Bell pair at different noise levels.

Sundry circuits

• Count gates : Counts gates in transpiled error correction circuits.

steanecode's Issues

Measurement for data qubit is not correct with FT ancilla

Need to delete graphs and figures

Need to reorganise to delete graphs and figures.

Need fault tolerant ancilla

Code fault tolerant ancilla.

Testing improvement

Improve accuracy of testing by checking results specifically against desired state "0000000".

Change encoding circuit to give an option to reduce by one the number of CX gates

Paetznick and Reichardt [1] suggest a method of reducing the CX gates in the encoding circuit by one. Change the code to allow this to be implemented.

[1] Paetznick A, Reichardt BW. Fault-tolerant ancilla preparation and noise threshold lower bounds for the 23-qubit Golay code. Quantum Inf Comput [Internet]. 2011 Jun 11 [cited 2021 Jul 17];12(11–12):1034–80. Available from: https://arxiv.org/abs/1106.2190v2

Change titles for workbooks for FT scheme B and C

Change titles

Tidy up docutexts

Change diagram in documentation

Existing diagram uses red and green, so it not suitable for some readers with color blindness.

Enhance testing framework

1. Test validation that can't run error correction with two logical qubits
2. Test validation that logical qubit index is in bounds
3. Test validation that physical qubit index is in bounds

Change documentation overview

The documentation overview needs to be updated to reference the Bacon Shor class.

Correct capitalisation in Workbook titles

Some have Steane code, not Steane Code.

Add new class for Bacon Shor code

• add new class to circuits.py
• update Bacon Shor worksheet

Final workbook versions

Place final versions of workbooks into GitHub after checking.

Code refactoring

Need to refactor code to remove variables like self.__data_0 by creating a list.

Upversion Steane Code master worksheet

1. Reformat diagram
2. Add initialisation at start of process. This happens anyway but is added for clarity.
3. Tidy up and recheck parameter settings.

Change definition of validity

In function process_FT_results add a new parameter post_select and if this is True only count codewords as not valid if outside the range.

Refactor correct_errors for issue found whilst documenting code

Make code more readible when handling case of two parity row matrices.

Change code so that the parity matrix is a list of strings

1. Change from list of lists to list of strings

Minor change to circuits.py documentation

Add _ to variable names in force_errors code

Remediate count_valid_output_strings

• allow post selection
• refactor code to be more logical

Remove deadcode

Tidy up and remove deadcode.

Add new output text to process_FT_results

Also, need to change logic for processing FT ancilla after testing.

Basic tests on a single qubit error

We need a test to verify that the impact on a single qubit is as predicted by the error model.

Add ancilla to Bacon Shor circuits

Change circuits.

Add new functions to return parity matrix and codewords.

Add to helper functions.

Updates to documentation

Need to update the documentation to include:

• overview
• documentation explanation
• notebook explanation

Also include the baseline workbook

Change title of documentation

Remove reference to MSc on conf.py

Refactor code to modularise standing data and register set up

Make new function modules to:

• define the standing data
• define the quantum registers

Documentation issues

1. Correct spelling in documentation index
2. Give more information in the overview

Include get_noise in helper functions

1. Add function module in helper functions
2. Change worksheets

Add more texts to circuits.py

Modify helper functions

Change helper functions to:

• add look up data
• modify summarise_logical_counts to use a list of values
• add convert codewords to change to a list of lists to a list of strings

Allow ability to measure FT logical encoding repetively

Need new test for error correction by code

Add new test to test_circuits.py

Add mean to graph in the basic single qubit worksheet.

• graph updated.

Code refactoring

Need to refactor code to remove variables like self.__data_0 by creating a list.

Documentation updates

Need:

• new documentation for helper functions module
• update documentation in test functions module for new tests
• change documentation in circuits module for changes to module
• regenerate documentation

Add new function to reset one qubit to enable new encoding scheme.

Add new function to reset one qubit. Set up new workbook to test scheme.

Change worksheet to include scheme D in comparison. Needed to change helper functions.

Fix bug in summarise logical counts

No key error returned.

Update to single qubit gates workbooks

1. Update documentation for single qubit gate workbook
2. Include Egan single qubit gate
3. Update Readme

Initialise ancilla

Initialise ancilla

Add further worksheets

-Steane_code_decoding_no_noise

• Basic single qubit errors transpilation
• Steane code decoding with noise
• Steane code error detection with noise
• Steane_Code_error_detection_no_noise
• Steane code logical operations with noise and without transpilation

Baseline release for noise model tests

• Improve documentation for baseline cases
• Include graphs
• Delete superseded workbooks

Add mean and standard deviation to worksheets

1. Change single qubit worksheet to add mean and standard deviation
2. Add new helper function to calculate mean of a list
3. Add new test of helper function

Need to be able to suppress ancilla rows

Change define registers to only set up registers needed.

Need a diagram of the Steane code in the overview

Add a diagram of the Steane code to the overview.

Code tidy up

Shorten code so less than 80 charactors per line if possible.

Python code changes

• Need a new module for helper functions
• Need to change circuits.py to allow two options for error correction
• Modify and add extra tests.

Jupyter Notebook

Tidy up Jupyter Notebook to remove reference to pipe cleaning

Baseline - Single qubit and two qubit errors