Mitiq

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.41.0...v0.42.0))

Highlights

🎊 Thanks for a great 2024! Our end of the year recap should be out soon. Subscribe [here](https://forms.gle/wVBki9n9ywA4c1Dj6) to get the newsletter in your mailbox.

🚀 Many thanks to **first time contributors** gluonhiggs, JMuff22, sanketsharma and Shivansh20128!

- gluonhiggs added support for some additional Qiskit gates through using gate decomposition for gates that are unavailable
in Cirq. A similar idea was applied to gates not recognized by QASM.
- Shivansh20128 added a new page in the documentation for benchmarking circuits.
- JMuff22 and sanketsharma corrected typos in the documentation.

💡 A new error-mitigation technique is on its way. Thanks to Misty-W for the
[Probabilistic Error Amplification RFC](https://docs.google.com/document/d/1l-74EFdMA0CSFUpHjqCyQYb3ZKCmY77seB1_mOZo5Co/edit?usp=sharing)!

🎏 Modular PEC functions are now available, courtesy of natestemen! These functions allow a
user to generate the intermediary sampled circuits and combine the results in a a two step process. E.g.

py
from mitiq import pec

circuits = pec.intermediary_sampled_circuits(circuit, representations)

sampled_circuit_results = ... execute the circuits on a simulator/hardware/toothbrush/etc

pec_estimate = pec.combine_results(sampled_circuit_results, ...)


✨ Enhancements

- Fix converting Rxx and similar Qiskit gates (2579) [gluonhiggs]
- Handle unsupported gates (2585) [gluonhiggs]
- RFC for Probabilistic Error Amplification technique (2550) [Misty-W]
- Address executor and observable incompatibility (2514) [bdg221]
- Modularize PEC functionality (2604) [natestemen]


🧑🏽‍💻 Developer Improvements

- Fix flaky ZNE factory + observable test (2602) [natestemen]
- Ensure further LRE compatibility with non-Cirq circuits (2599) [natestemen]
- Throw Erorr on Multiple Measurements per Qubit with Observables (2593) [bdg221]

📓 Documentation

- Update Calibration run docstring for API-doc (2516) [bdg221]
- Add benchmarking circuits to user guide (2566) [Shivansh20128]
- Correct run-on sentences in the API-doc for CDR function docstrings (2589) [Shivansh20128]
- Quick fix: Fix typo and headings in classical shadows tutorial (2574) [JMuff22]
- Update executor and observable docs (2594) [bdg221]
- Add log param to calibration guide (2568) [bdg221]
- Fix constant value in ZNE docs (2591) [cosenal]
- Fixed typo in documentation (2611) [sanketsharma]

📦 Dependency Updates

- Update qiskit requirement from ~=1.2.4 to ~=1.3.1 (2603) [dependabot, cosenal]
- Update qibo requirement from ~=0.2.7 to ~=0.2.13 (2559) [dependabot]
- Bump pyqrack from 1.32.21 to 1.32.27 (2582) [dependabot, natestemen]
- Bump codecov/codecov-action from 4 to 5 (2576) [dependabot]
- Bump pyqrack from 1.32.11 to 1.32.21 (2580) [dependabot]

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.40.0...v0.41.0))

Highlights

📓 The Layerwise Richardson Extrapolation **(LRE) user guide is complete**!
The user guide contains information about both the ins and outs of using the implementation, as well as covering the theory behind the technique so you can make judgements about when to apply the technique.
In addition to finishing the user guide, we also have a new tutorial comparing both the performance and overhead needed for LRE and ZNE.
Big thanks to purva-thakre and FarLab for the documentation!

📹 As part of launching LRE we made a **short tutorial video** to showcase the technique, along with how to use it.
Check it out [here](https://www.youtube.com/watch?v=47GWi4h7TWM)!

🧑‍🔬 **First time contributor** jpacold recreated results from [a paper](https://arxiv.org/abs/2211.08318) on phase transitions in the Ising model.
Both the paper authors, and jpacold both used Mitiq's ZNE module to apply error mitigation.
This is both an informative tutorial on turning physics problems into something amenable on a quantum computer, and a class in applying error-mitigation.

✨ Enhancements

- Ensure LRE compatibility with all supported frontends (2547) [natestemen]

🧑🏽‍💻 Developer Improvements

- remove failing test; simplify layerwise ZNE tests (2545) [natestemen]

📞 Call for ideas

We're currently looking into what features we could add to make Mitiq more **noise-aware**.
If you have ideas and features requests in this area, do make a post on the GitHub discussion [here](https://github.com/unitaryfund/mitiq/discussions/2193)!

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.39.0...v0.40.0))

Highlights

🔉 A new quantum error-mitigation technique is available in Mitiq!
**Layerwise Richardson Extrapolation** is now available through `mitiq.lre.execute_with_lre`.
Documentation is also available in the user guide, with more advanced docs and demonstrations coming in the next release.
Special thanks to Purva Thakre for this contribution!

🥇 We had two **first time contributions** from ecarlander and mbrotos!
Thank you both for your contributions!

🛡️ A **helpful error message** is raised when passing data of the incorrect type to the `MeasurementResult` class, where before it silently gave confusing results.

✨ Enhancements
- LRE Executors (2499) [purva-thakre]
- LRE Inference Functions (2447) [purva-thakre]
- Raise TypeError when a dictionary is passed to MeasurementResult constructor (2523) [natestemen]

📓 Documentation

- Add theory, intro and use case pages of LRE user guide (2522) [purva-thakre]
- add QOSS survey banner (2533) [natestemen]
- Update broken link in the readme (2528) [purva-thakre]
- Move class documentation to class docstrings (2525) [natestemen]
- QSE docs cleanup (2490) [natestemen]
- Add tags to tutorials (2467) [purva-thakre]
- Correct CDR and VNCDR acronyms in example (2479) [bdg221]
- added roadmap link to readme (2468) [ecarlander]
- Update ibmq-backends.md (2474) [mbrotos]

🧑🏽‍💻 Developer Improvements

- Remove `make requirements` (2481) [purva-thakre]
- Fix flaky REM test / refactor (2464) [natestemen]

📦 Dependency Updates

- Bump pyscf from 2.6.2 to 2.7.0 (2518) [dependabot]
- Bump pyqrack from 1.30.24 to 1.30.30 (2521) [dependabot]
- Bump pyqrack from 1.30.22 to 1.30.24 (2497) [dependabot]
- Update qiskit requirement from ~=1.2.1 to ~=1.2.2 (2507) [dependabot]
- Bump qibo from 0.2.10 to 0.2.12 (2506) [dependabot]
- Update qiskit-aer requirement from ~=0.15.0 to ~=0.15.1 (2504) [dependabot]
- Update qiskit requirement from ~=1.2.0 to ~=1.2.1 (2503) [dependabot]
- Bump pyqrack from 1.30.20 to 1.30.22 (2489) [dependabot]
- Update qiskit-aer requirement from ~=0.14.2 to ~=0.15.0 (2484) [dependabot]
- Bump pyqrack from 1.30.8 to 1.30.20 (2487) [dependabot]
- Update cirq-core requirement from <1.4.0,>=1.0.0 to >=1.0.0,<1.5.0 (2390) [dependabot]
- Update qiskit requirement from ~=1.1.1 to ~=1.2.0 (2482) [dependabot]
- Update scipy requirement from <=1.14.0,>=1.10.1 to >=1.10.1,<=1.14.1 (2477) [dependabot]
- Bump pyqrack from 1.30.0 to 1.30.8 (2476) [dependabot]
- Bump sphinx from 7.2.6 to 8.0.2 (2455) [dependabot]
- Bump qibo from 0.2.9 to 0.2.10 (2458) [dependabot]

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.38.0...v0.39.0))

Highlights

We've made updates to our documentation, beginning with the completion of the first section of the Pauli Twirling user guide, which offers a comprehensive introduction to this feature.
Additionally, we've added a new tutorial on CDR (Clifford Data Regression) using [Qrack](https://github.com/unitaryfund/qrack/) as an efficient near-Clifford simulator.
This demonstrates a workflow that harnesses the speed of Qrack in the CDR training phase, while providing users with an in-depth look at how to integrate Mitiq and Qrack effectively.

📓 Documentation

- Complete first section of Pauli Twirling user guide (2454) [cosenal]
- Hide primary sidebar from certain pages of the documentation (2424) [purva-thakre]
- CDR Tutorial with Qrack (2451) [bdg221]

🧑🏽‍💻 Developer Improvements

- Separate docs build workflow (2441) [purva-thakre]
- clean and git ignore all coverage reports (2443) [cosenal]
- Ignore _about.py in pytest coverage (2379) [purva-thakre]
- use date to make version unique for testpypi uploads (2436) [natestemen]

📦 Dependency Updates

- Update scipy requirement from <=1.13.1,>=1.10.1 to >=1.10.1,<=1.14.0 (2420) [dependabot]

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.37.0...v0.38.0))

Highlights

🚀 As of this release, thanks to natestemen, **we are officially supporting Python 3.12 and dropping Python 3.9**.

🌉 As part of UnitaryHack 2024, new contributor NnguyenHTommy **fixed a Qiskit to Cirq gate conversion error** by implementing a fallback mechanism to decompose and transpile the Qiskit circuit into native Cirq gates.

🌀 Another Unitary Hacker, EmilianoG-byte **added functionality to simulate noise specifically on CNOT and CZ gates when using the Pauli Twilring technique** to symmetrize errors.

🔉 As hinted in last release's spoilers, purva-thakre has **implemented the noise scaling functionality required for the Layerwise Richardson Extrapolation (LRE) technique**, which allows a more fine-grained control over the amount of noise in circuits compared to the standard unitary folding method.

✨ Enhancements
- **Noise Scaling for LRE** (2347) [purva-thakre]
- **Issue 2354 Fix - qiskit QFT gates error during conversion** (2404) [NnguyenHTommy]
- **Simulate noise for CNOT and CZ gates in Pauli Twirling** (2397) [EmilianoG-byte]

🛠️ Maintenance and Upkeep Improvements
- Update readme (2421) [purva-thakre]
- Update README with Github discussion link (2419) [bdg221]
- Update contributing guide (2382) [purva-thakre]

🧑🏽‍💻 Dev Environment Improvements
- Used trusted publishers for testpypi publishing (2320) [natestemen]
- bump min python version for intersphinx map (2425) [natestemen]
- **Support python 3.12 and drop 3.9** (2066) [natestemen]

📦 Dependency Updates
- Bump qibo from 0.2.8 to 0.2.9 (2430) [dependabot[bot]]
- Update qiskit requirement from ~=1.1.0 to ~=1.1.1 (2414) [dependabot[bot]]
- Bump pyscf from 2.6.0 to 2.6.2 (2415) [dependabot[bot]]

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.36.0...v0.37.0))

Highlights

✨ Stacking quantum error mitigation techniques is a primary area of focus in Mitiq. In this release, jordandsullivan introduced a **Tutorial on composing Digital Dynamical Decoupling (DDD) and Zero Noise Extrapolation (ZNE)**.

🗒️ **»Download Notebook«**: Users have now the option to download tutorials in Jupyter `.ipynb` format directly from our documentation. We hope this will encourage experimentation with existing tutorials.

🤐 Lastly, a spoiler on what's upcoming: a Request for Comments document by purva-thakre on adding **Layerwise Noise-Scaling and Multivariate Richardson Extrapolation** has been reviewed and approved. These techniques will soon make their way into Mitiq, stay tuned!


Enhancements
- Add the RFC LRE link (2329) [purva-thakre]
- Example stacking DDD and ZNE (2345) [jordandsullivan]
- Add download notebook link in docs (2363) [cosenal]
- Add example near-Clifford circuit simulators with links (2367) [bdg221]

Maintenance and upkeep improvements
- Remove qiskit-ibm-provider (2342) [andre-a-alves]
- Delete old version of diagram, as unnecessary (2364) [jordandsullivan]
- Remove duplicate readme entry in toctree (2362) [jordandsullivan]
- Update glossary (2355) [purva-thakre]
- Update QSE diagram to call module mitiq.qse, add versions to images, update references to point to v2 image (2361) [jordandsullivan]
- Updated docstring for `generate_mirror_circuits` (2353) [jordandsullivan]
- Pretty print supported programs enum (2352) [cosenal]

Dev environment improvements
- Document tip for easily generating release note (2398) [cosenal]
- Missing unit tests for benchmarking circuits (2366) [purva-thakre]

📦 Dependency updates
- Bump pyscf from 2.5.0 to 2.6.0 (2396) [dependabot[bot]]
- Update qiskit-aer requirement from ~=0.14.0.1 to ~=0.14.2 (2393) [dependabot[bot]]
- Update scipy requirement from <=1.13.0,>=1.10.1 to >=1.10.1,<=1.13.1 (2380) [dependabot[bot]]
- Bump qibo from 0.2.7 to 0.2.8 (2385) [dependabot[bot]]
- Update qiskit requirement from ~=1.0.2 to ~=1.1.0 (2369) [dependabot[bot]]
- Update pennylane-qiskit requirement from ~=0.35.1 to ~=0.36.0 (2350) [dependabot[bot]]
- Update pennylane requirement from ~=0.35.1 to ~=0.36.0 (2349) [dependabot[bot]]