v0.21.0

Summary

This release officially adds support for the learning-based PEC sub-technique which is now fully documented and ready to be applied by Mitiq users. We are still assessing the stability of this new sub-technique, so if you notice any bugs, please let us know by opening issues on GitHub.

Functions to apply Readout Error Mitigation (REM) are also introduced in this release, special thanks to Amir Ebrahimi for this contribution!

Also, the noise scaling by identity insertion method is included in the ZNE section of the user guide. Special thanks to Purva Thakre for this contribution!

During the release cycle we accepted the RFC for implementation of calibration tools (Solution 1). We also completed a prototype of this approach, which will be released in a future version of Mitiq.

In addition, this release adds support for qubit-independent representations for PEC, along with bug fixes and minor dependency upgrades.

What's Changed

• Set master in dev mode for Milestone 0.21 by @Misty-W in #1575
• use python 3.10 for asv by @natestemen in #1580
• Update qiskit requirement from ~=0.39.0 to ~=0.39.1 by @dependabot in #1579
• Update qiskit requirement from ~=0.39.1 to ~=0.39.2 by @dependabot in #1581
• Update amazon-braket-sdk requirement from ~=1.31.1 to ~=1.33.1 by @dependabot in #1585
• Update amazon-braket-sdk requirement from ~=1.33.1 to ~=1.33.2 by @dependabot in #1588
• color output from pytest on CI by @natestemen in #1587
• Update pennylane-qiskit requirement from ~=0.24.0 to ~=0.27.0 by @dependabot in #1591
• Learn biased noise parameters by @Misty-W in #1510
• Update amazon-braket-sdk requirement from ~=1.33.2 to ~=1.34.0 by @dependabot in #1589
• Update amazon-braket-sdk requirement from ~=1.34.0 to ~=1.34.1 by @dependabot in #1595
• use \prod instead of \Pi by @natestemen in #1592
• Raise error when inserting DDD sequence with midcircuit measurement by @natestemen in #1586
• Write user guide section for learning-based PEC by @Misty-W in #1395
• remove skipped test by @natestemen in #1598
• Update amazon-braket-sdk requirement from ~=1.34.1 to ~=1.34.3 by @dependabot in #1599
• Update numpy requirement from ~=1.23.4 to ~=1.23.5 by @dependabot in #1600
• REM implementation by @amirebrahimi in #1449
• Cleanup (some) Deprecation Warnings by @purva-thakre in #1556
• Refactor generate_inverse_confusion_matrix by @amirebrahimi in #1607
• Enable user to define qubit-independent representations by @Misty-W in #1565
• Update pennylane requirement from ~=0.26.0 to ~=0.27.0 by @dependabot in #1590
• Documentation for Identity Scaling by @purva-thakre in #1573
• Techniques intro by @nathanshammah in #1603
• Bump flake8 from 5.0.4 to 6.0.0 by @dependabot in #1609
• Update qiskit requirement from ~=0.39.2 to ~=0.39.3 by @dependabot in #1611
• prepare v0.21.0 release by @Misty-W in #1613

Full Changelog: v0.20.0...v0.21.0

v0.20.0

Summary

This milestone focused on updating our support for numpy (1.23), adding a tutorial demonstrating the learning-based PEC workflow, and scoping out what device/noise calibration might look like as part of Mitiq. Additionally identity insertion has been added as a noise-scaling technique available for mitigation protocols such as zero-noise extrapolation. Expect more documentation of this feature in future releases. Big thanks to @purva-thakre for getting this in Mitiq!

There are also some minor bug fixes, documentation updates, and a new example contributed by @nickdgardner as well!

All changes

• Port BQSKit example to 1.0 release (#1557) [@natestemen]
• Add Qiskit example on mitigating the energy landscape of a variational circuit (#1551) [@nickdgardner]
• Bump pytest-xdist[psutil] from 2.5.0 to 3.0.2 (#1569) [@dependabot]
• remove badges from contributing to docs doc (#1571) [@natestemen]
• Warn when unsupported gate fidelity is passed (#1542) [@natestemen]
• remove gh-pages deploy action (#1566) [@natestemen]
• First demo of learning function (#1514) [@Misty-W]
• remove stale bot (#1558) [@natestemen]
• Update scipy requirement from ~=1.9.2 to ~=1.9.3 (#1561) [@dependabot]
• Docs infrastructure improvements (#1559) [@natestemen]
• Identity Insertion Scaling (#1442) [@purva-thakre]
• Update scipy requirement from ~=1.9.1 to ~=1.9.2 (#1548) [@dependabot]
• Update amazon-braket-sdk requirement from ~=1.31.0 to ~=1.31.1 (#1549) [@dependabot]
• Update qiskit requirement from ~=0.38.0 to ~=0.39.0 (#1550) [@dependabot]
• Update numpy requirement from ~=1.23.3 to ~=1.23.4 (#1553) [@dependabot]
• Revert "[temporary] ignore errors from first-interaction (#1532)" (#1555) [@natestemen]
• allow all tests to run if one fails (#1554) [@natestemen]
• Update numpy requirement from ~=1.21.6 to ~=1.23.3 (#1486) [@dependabot]
• Update black requirement from ~=22.8 to ~=22.10 (#1544) [@dependabot]
• Update pydata-sphinx-theme requirement from ~=0.10.1 to ~=0.11.0 (#1545) [@dependabot]
• add robots.txt 🤖 (#1543) [@natestemen]
• Set master in dev mode (#1536) [@andreamari]
• Update mypy requirement from ~=0.981 to ~=0.982 (#1537) [@dependabot]
• Update pyquil requirement from ~=3.3.1 to ~=3.3.2 (#1539) [@dependabot]

v0.19.0

Changelog

Version 0.19.0

Summary

With this release Mitiq supports most recent versions of Python: 3.8, 3.9 and 3.10!
We drop support for Python 3.7.

Mitiq is now compatible with Numpy 1.21.6. Different versions of NumPy may not work properly.

Another important update is the addition of new tools for applying learning-based PEC!
This release introduces a function for learning depolarizing noise representations from Clifford circuit data.
Read more in our updated API-doc.

Special thanks to the external contributors @yitchen-tim, @amirebrahimi and @isaac-gs!

All Changes

• Implement conversions of IonQ native gates for Braket (#1525) [@yitchen-tim]
• [temporary] ignore errors from first-interaction (#1532) [@natestemen]
• Update sphinx-autodoc-typehints requirement from ~=1.12.0 to ~=1.19.4 (#1515) [@dependabot]
• Update pytest-cov requirement from ~=3.0.0 to ~=4.0.0 (#1521) [@dependabot]
• Update myst-nb requirement from ~=0.16.0 to ~=0.17.1 (#1529) [@dependabot]
• replace deprecated execution_excludepatterns (#1530) [@natestemen]
• Support python 3.10 (#1504) [@natestemen]
• Fix outdated link in README (2021 -> 2022) (#1528) [@andreamari]
• Add learning-based PEC subsection in API doc (#1524) [@nathanshammah]
• remove print calls (#1519) [@natestemen]
• BQSKit tutorial (#1489) [@natestemen]
• Update pyquil requirement from ~=3.3.0 to ~=3.3.1 (#1516) [@dependabot]
• Update scipy requirement from ~=1.7.3 to ~=1.9.1 (#1467) [@dependabot]
• Update mypy requirement from ~=0.971 to ~=0.981 (#1511) [@dependabot]
• (partially) upgrade numpy (#1501) [@natestemen]
• Update amazon-braket-sdk requirement from ~=1.30.2 to ~=1.31.0 (#1512) [@dependabot]
• Add whitepaper publication info/links (#1456) [@natestemen]
• Support python 3.9 (#1505) [@natestemen]
• Learning function for biased noise (#1358) [@Misty-W]
• Update amazon-braket-sdk requirement from ~=1.30.1 to ~=1.30.2 (#1506) [@dependabot]
• Bump actions/stale from 5 to 6 (#1502) [@dependabot]
• Update amazon-braket-sdk requirement from ~=1.30.0 to ~=1.30.1 (#1499) [@dependabot]
• Restore the titles of the examples in the Mitiq docs (#1497) [@andreamari]
• Update amazon-braket-sdk requirement from ~=1.29.4 to ~=1.30.0 (#1492) [@dependabot]
• Bump codecov/codecov-action from 3.1.0 to 3.1.1 (#1496) [@dependabot]
• removed unused lindblad doc (#1494) [@natestemen]
• Update pennylane requirement from ~=0.25.1 to ~=0.26.0 (#1495) [@dependabot]
• [MCMC 1/3] Moving clifford utils for cdr to own files (#1480) [@isaac-gs]
• Update qiskit requirement from ~=0.37.2 to ~=0.38.0 (#1490) [@dependabot]
• docs: add amirebrahimi as a contributor for code, test, doc (#1487) [@allcontributors]
• Move MeasurementResult into _typing to fix circular dependency in #1449 (#1484) [@amirebrahimi]
• Update amazon-braket-sdk requirement from ~=1.29.3 to ~=1.29.4 (#1483) [@dependabot]

v0.18.0

This release cycle focused on review and approval of two RFCs, one for Readout Error Mitigation (REM) #1387 and one for Identity insertion noise scaling #335 (not listed as PRs). It also includes bug fixes and minor dependency upgrades.

What's Changed

• 0.18.0 in dev by @natestemen in #1433
• Add executor with a backend argument in mitiq_qiskit utils by @andreamari in #1409
• Update pyquil requirement from ~=3.2.1 to ~=3.3.0 by @dependabot in #1436
• Update amazon-braket-sdk requirement from ~=1.28.1 to ~=1.29.0 by @dependabot in #1437
• Update sphinxcontrib-bibtex requirement from ~=2.4.2 to ~=2.5.0 by @dependabot in #1457
• remove patch release docs by @natestemen in #1435
• Simplify issue/PR templates by @natestemen in #1315
• Update amazon-braket-sdk requirement from ~=1.29.0 to ~=1.29.2 by @dependabot in #1459
• Update qiskit requirement from ~=0.37.1 to ~=0.37.2 by @dependabot in #1458
• Mid circuit measurement fixed for ddd by @Aaron-Robertson in #1446
• Update black requirement from ~=22.6 to ~=22.8 by @dependabot in #1477
• Update pennylane requirement from ~=0.24.0 to ~=0.25.1 by @dependabot in #1444
• docs: add 1ucian0 as a contributor for infra, code by @allcontributors in #1461
• docs: add Aaron-Robertson as a contributor for ideas, code, doc by @allcontributors in #1464

Full Changelog: v0.17.1...v0.18.0

Release v0.17.1

Changelog

Version 0.17.1

Summary

This patch release includes support for the latest versions of Qiskit (0.37.1), Cirq (1.0.0), and Pyquil (3.2.1), along with other minor dependency upgrades and bug fixes.

All Changes

• Update pyquil requirement from ~=3.0.0 to ~=3.2.1 (#1425) [@dependabot]
• Update cirq requirement from ~=0.15.0 to ~=1.0.0 (#1402) [@dependabot]
• Add fold methods as parameters to benchmarks (#1374) [@natestemen]
• Updates tests and docstrings for cirq utils (#1371) [@purva-thakre]
• Update amazon-braket-sdk requirement from ~=1.27.1 to ~=1.28.1 (#1430) [@dependabot]
• Bump openfermion from 1.5.0 to 1.5.1 (#1429) [@dependabot]
• Update flake8 requirement from ~=5.0.3 to ~=5.0.4 (#1423) [@dependabot]
• Update flake8 requirement from ~=4.0.1 to ~=5.0.3 (#1419) [@dependabot]
• Support for Qiskit 0.37 (#1421) [@1ucian0]
• Update amazon-braket-sdk requirement from ~=1.26.1 to ~=1.27.1 (#1417) [@dependabot]
• Bump openfermion from 1.3.0 to 1.5.0 (#1412) [@dependabot]
• Update amazon-braket-sdk requirement from ~=1.26.0 to ~=1.26.1 (#1405) [@dependabot]
• Update mypy requirement from ~=0.961 to ~=0.971 (#1406) [@dependabot]
• Update release docs (#1404) [@natestemen]
• Update amazon-braket-sdk requirement from ~=1.25.2 to ~=1.26.0 (#1403) [@dependabot]
• update version.txt to dev (#1398) [@natestemen]
• Prevent idle qubits with qiskit barriers from being lost after conversions (#1369) [@andreamari]
• Add custom RTD favicon (#1390) [@natestemen]
• Update python-rapidjson requirement from <=1.6 to <1.8 (#1389) [@dependabot]

Release v0.17.0

Changelog

Version 0.17.0 (July 6th, 2022)

Summary

This release includes contributions from UnitaryHACK 2022! 🎉 We had 3 merged pull requests, and a fourth is looking to be merged in the next milestone. Along with the great contributions from hackers, this release focused on expanding our ZNE examples to other frontends (Cirq, Braket, and Pennylane), building out learning-based PEC, and improving our benchmarking infrastructure.

All Changes

• Support the latest Cirq version (0.15.0) (@andreamari, gh-1379)
• add ZNE example using pennylane (@natestemen, gh-1384)
• Add ZNE example with Braket and IonQ (@andreamari, gh-1363)
• docs: add natestemen as a contributor for infra, doc, test, code (allcontributors, gh-1383)
• remove comma (@natestemen, gh-1381)
• add myself to authors (@natestemen, gh-1372)
• Deploy asv benchmark data to web (@natestemen, gh-1354)
• Batched mitigate (@nylewong, gh-1286)
• Update black requirement from ~=22.3 to ~=22.6 (@dependabot, gh-1370)
• Add Error Mitigation example with Cirq (@Misty-W, gh-1351)
• Update amazon-braket-sdk requirement from ~=1.25.1 to ~=1.25.2 (@dependabot, gh-1367)
• Update pennylane-qiskit requirement from ~=0.23.0 to ~=0.24.0 (@dependabot, gh-1361)
• Update Mitiq paper code blocks based on paper review (@andreamari, gh-1357)
• Update pennylane requirement from ~=0.23.1 to ~=0.24.0 (@dependabot, gh-1362)
• Update amazon-braket-sdk requirement from ~=1.25.0 to ~=1.25.1 (@dependabot, gh-1359)
• Improving the H2 example (@obliviateandsurrender, gh-1337)
• Test on windows and mac on each PR and add openfermion to dev requirements (@andreamari, gh-1348)
• Loss function for learning biased noise (@Misty-W, gh-1340)
• Modify docstrings, documentation to use citations from refs.bib [unitaryhack] (@WingCode, gh-1325)
• [unitaryhack] v2 Updated molecular hydrogen tutorial OpenFermion (@lockwo, gh-1349)
• Update amazon-braket-sdk requirement from ~=1.24.0 to ~=1.25.0 (@dependabot, gh-1345)
• Bump actions/setup-python from 3 to 4 (@dependabot, gh-1344)
• [unitaryhack] Add thumbnails for examples (@obliviateandsurrender, gh-1338)
• Revert "[unitaryhack] Updated molecular hydrogen tutorial" (@andreamari, gh-1347)
• [unitaryhack] Updated molecular hydrogen tutorial (@lockwo, gh-1296)
• Update mypy requirement from ~=0.960 to ~=0.961 (@dependabot, gh-1342)
• Merge pull request #1320 from unitaryfund/nts-contrib-docs (@natestemen)

Release v0.16.0

Changelog

Version 0.16.0 (June 3rd, 2022)

Summary

This release officially adds support for the digital dynamical decoupling (DDD) technique which is now fully documented and so ready to be applied by Mitiq users. This is still very new technique and so, if you notice any bugs, please let us know by
opening issues on GihHub.
A further notable addition is the function generate_quantum_volume_circuit() by @nickdgardner, extending the Mitiq benchmarking module with quantum volume
circuits.

Congratulations to the new member of the Mitiq team @natestemen and special thanks to the external contributors @Aaron-Robertson, @nickdgardner, @ZhaoyiLi-HekJukZaaiZyuJan and @amirebrahimi!

All Changes

• Add section 2 (use case) on DDD to user guide (@nathanshammah, gh-1304)
• Update DDD options documentation (third section) (@andreamari, gh-1327)
• Add additional options subsection for DDD (third section) (@Aaron-Robertson, gh-1326)
• Add theory subsection for DDD (fifth section) (@andreamari, @natestemen, gh-1311)
• Update amazon-braket-sdk requirement from ~=1.19.0 to ~=1.24.0 (@dependabot gh-1324, gh-1310, gh-1306, gh-1303, gh-1297, gh-1278, gh-1271)
• Ensure lists in documentation are displayed properly (@natestemen, gh-1322)
• Add quantum volume circuits to benchmarking module (@nickdgardner, gh-1281)
• Update readme table with DDD (@andreamari, gh-1318)
• Test PR for unitaryhack test bounty (@nathanshammah, gh-1317)
• Fixes unexpected error from repeated rule (@Aaron-Robertson, gh-1316)
• Update mypy requirement from ~=0.950 to ~=0.960 (@dependabot, gh-1314)
• Use single URL when referring to google style (@natestemen, gh-1309)
• Update close-stale.yml (@andreamari, gh-1295)
• Update contributing docs (@amirebrahimi, gh-1305)
• Add fourth section of DDD docs (@andreamari, gh-1276)
• Fix citation file (@natestemen, gh-1299)
• Write the first sub-section of the DDD guide: How do I use DDD? (@Misty-W, gh-1277)
• Update qiskit requirement from ~=0.36.1 to ~=0.36.2 (@dependabot, gh-1302)
• Rename test_randomized_benchmaking.py to test_randomized_benchmarking.py (@nickdgardner, gh-1284)
• Fix broken links in docs (@andreamari, gh-1282)
• Create file structure (@andreamari, gh-1275)
• Update pennylane requirement from ~=0.23.0 to ~=0.23.1 (@dependabot, gh-1274)
• Fixed typo in documentation formula (@ZhaoyiLi-HekJukZaaiZyuJan, gh-1246)
• Update version to 0.16dev (@nathanshammah, gh-1268)

Release v0.15.0

Changelog

Version 0.15.0 (April 29th, 2022)

Summary

This milestone focused on updating dependencies and making progress on two new features, dynamical decoupling and learning based PEC. For dynamical decoupling, high-level functions and rules were added. For learning-based PEC, a function calculating representations with a biased (combination of depolarizing and dephasing) noise model was added. Several high priority bugs and issues were also fixed.

Special thanks to new contributors @RubidgeCarrie and @nickdgardner for their contributions to this release!

All Changes

• Add digital dynamical decoupling high-level functions (@andreamari, gh-1251)
• Fix qubit naming in OperationRepresentations for Qiskit circuits (@Misty-W, gh-1238)
• Fix broken link in contributing guide (@Misty-W, gh-1257)
• Insert sequences for dynamical decoupling (@Aaron-Robertson, gh-1221)
• Short sequences in DDD API docs (@andreamari, gh-1237)
• Update pennylane-qiskit requirement from ~=0.22.0 to ~=0.23.0 (@dependabot, gh-1249)
• Update qiskit requirement from ~=0.36.0 to ~=0.36.1 (@dependabot, gh-1242)
• Update pennylane requirement from ~=0.22.2 to ~=0.23.0 (@dependabot, gh-1248)
• Move the gh pages deploy to a manually triggered action (@crazy4pi314, gh-1243)
• Update AUTHORS (@nickdgardner, gh-1239)
• fix typo (@nickdgardner, gh-1240)
• Add DDD to Api-Doc, fixes #1209 (@nathanshammah, gh-1226)
• Add rules for dynamical decoupling (@Aaron-Robertson, gh-1202)
• Fix compilation to native gateset in Braket notebook (@andreamari, gh-1225)
• Update amazon-braket-sdk requirement from ~=1.17.0 to ~=1.19.0 (@ dependabot, 1235)
• Function to represent OperationRepresentations for biased noise (@Misty-W, gh-1233)
• Bump codecov/codecov-action from 2.1.0 to 3.0.0 (@dependabot, gh-1216)
• Bump actions/stale from 4 to 5 (@dependabot, gh-1217)
• Update sphinxcontrib-bibtex requirement from ~=2.4.1 to ~=2.4.2 (@dependabot, gh-1218)
• Update cirq requirement from ~=0.14.0 to ~=0.14.1 @dependabot, gh-1219)
• Added citiation file for the repo (RubidgeCarrie, gh-1200)
• Add mitigate_executor and cdr_decorator to mitiq.cdr (@Aaron-Robertson, gh-1204)
• Update qiskit requirement from ~=0.35.0 to ~=0.36.0 (@dependabot, gh-1213)

Release v0.14.0

Changelog

Version 0.14.0 (April 6th, 2022)

Summary

This milestone focused on updating dependencies and making progress on two new features, dynamical decoupling and learning based error mitigation techniques. A number of high priority bugs and issues alo were fixed.

All Changes

• Update pennylane requirement from ~=0.22.1 to ~=0.22.2 (@dependabot, gh-1203)
• Update mypy requirement from ~=0.931 to ~=0.942 (@dependabot, gh-1183)
• Update pennylane-qiskit requirement from ~=0.20.0 to ~=0.22.0 (@dependabot, gh-1170)
• Update pennylane requirement from ~=0.21.0 to ~=0.22.1 (@dependabot, gh-1172)
• Update qiskit requirement from ~=0.34.2 to ~=0.35.0 (@dependabot, gh-1199)
• Update black requirement from ~=22.1 to ~=22.3 (@dependabot @andreamari @crazy4pi314, gh-1191)
• Avoid creation of empty moments when using fold_global (@andreamari, gh-1196)
• Merge pull request #1198 from unitaryfund/1140-raise-error-if-executo (@Misty-W)
• Port changes from old branch - workaround (@Misty-W)
• Merge pull request #1195 from unitaryfund/update-qiskit (@Misty-W)
• Update docs/source/guide/pec-3-options.myst @crazy4pi314 (@Misty-W)
• Merge branch 'master' into update-qiskit (@crazy4pi314)
• Update Cirq to 0.14 (@andreamari, gh-1193)
• fix pec-3-options notebook problem (@andreamari)
• Remove option to squash moments in global folding (@purva-thakre @andreamari, gh-1113)
• update qiskit and fix conversions (@andreamari)
• Idle qubits in conversion (@Aaron-Robertson, gh-1185)
• Add get_circuit_mask() for dynamical decoupling (@Aaron-Robertson, gh-1178)
• Update pydata-sphinx-theme requirement from ~=0.8.0 to ~=0.8.1 (@dependabot, gh-1188)
• Add get_slack_matrix_from_circuit_matrix() function for dynamical decoupling (@andreamari @Aaron-Robertson,gh-1178)
• Fix sphinx dependency problem (@andreamari , gh-1181)
• Create file structure for digital dynamical decoupling (@andreamari, gh-1175)
• adding pages publish step (@crazy4pi314,gh-1135)
• cast gate exponents to float (@andreamari,gh-1174)
• Update release.rst (@andreamari,gh-1145)
• Bump actions/setup-python from 2 to 3 (@dependabot, gh-1149)
• Bump actions/checkout from 2 to 3 (@dependabot, gh-1151)
• Update amazon-braket-sdk requirement from ~=1.15.0 to ~=1.17.0 (@dependabot, gh-1153)
• fixing install permissions, container user is root (@crazy4pi314 , gh-1147)

Release v0.13.0

Changelog

Version 0.13.0 (February 25th, 2022)

Summary

Mitiq is now compatible with the latest version (0.13.1) of Cirq! This update was blocked for a long time because of some technical difficulties. So, many thanks to @vtomole for finding a solution to this issue!
This should solve several dependency conflicts or warnings that you may have got when running pip install mitiq or pip install -U mitiq.

The HTML rendering of all PyQuil examples in our documentation is now fixed. Thanks @astrojuanlu for useful suggestions about readthedocs!

We also thank @Rahul-Mistri for adding GHZ circuits to our benchmarking module and for making Clifford circuits compatible with the Mitiq CDR technique (instead of raising an error as it happened before this release).

We discussed and approved the design documents (RFC) for two new error-mitigation techniques: learning-based PEC and digital dynamical decoupling. You can find them at this link. Special thanks go to @Misty-W and @Aaron-Robertson!

All Changes

• Add pre-executed pyquil notebooks (@andreamari, gh-1142)
• Fix optimal representation tests and unskip one of them (@andreamari gh-1141)
• Update amazon-braket-sdk requirement from ~=1.11.1 to ~=1.15.0 (@dependabot, gh-1137, gh-1116, gh-1108, gh-1105)
• Update black requirement from ~=19.10b0 to ~=22.1 (@dependabot, @crazy4pi314, gh-1110)
• Bump actions/github-script from 5 to 6 (@dependabot, gh-1129)
• Update mypy requirement from ~=0.930 to ~=0.931 (@dependabot, gh-1078)
• docs: add vtomole as a contributor for test, code (@allcontributors, @andreamari, gh-1132)
• docs: add Rahul-Mistri as a contributor for test, code (@allcontributors, @andreamari, gh-1130)
• docs: add L-P-B as a contributor for test, code (@allcontributors, gh-1131)
• Update PR template (@nathanshammah, gh-1117)
• Remove unused functions from cirq_utils and fix non-deterministic tests. (@andreamari gh-1123)
• Update pennylane requirement from ~=0.20.0 to ~=0.21.0 (@dependabot, gh-1122)
• Bump cirq version from 0.10.0 to 0.13.0 (@vtomole, gh-988)
• Can use Clifford Circuits with execute_with_cdr (@Rahul-Mistri, gh-1104)
• Docstring for GHZ-circuits reformatted (@Rahul-Mistri, gh-1101)