Mitiq

All Changes

- Fix broken links on the website (erkska, gh-400).
- Use cirq v0.9.0 instead of cirq-unstable (karalekas, gh-402).
- Update mitiq.about() (rmlarose, gh-399).
- Refresh the release process documentation (karalekas, gh-392).
- Redesign factories, batch runs in BatchedFactory, fix Qiskit utils tests (rmlarose, andreamari, gh-381).
- Add note on batched executors to docs (rmlarose, gh-405).
- Added Tensorflow Quantum executor to docs (k-m-schultz, gh-348).
- Fix a collection of small build & docs issues (karalekas, gh-410).
- Add optimal QPR decomposition for depolarizing noise (karalekas, gh-371).
- Add PEC basic implementation assuming a decomposition dictionary is given (andreamari, gh-373).
- Make tensorflow requirements optional for docs (karalekas, gh-417).

Thanks to erkska and k-m-schultz for their contributions to this release!

│ Scale method: fold_global │ Improvement factor: 0.3333 │ Improvement factor: 0.9709 │
├────────────────────────────────────┼────────────────────────────┼────────────────────────────┤
│ Technique: ZNE │ ✘ │ ✔ │
│ Factory: Richardson │ Noisy error: 0.03 │ Noisy error: 1.0 │

│ Scale method: fold_global │ Improvement factor: 0.72 │ Improvement factor: 1.0025 │
└────────────────────────────────────┴────────────────────────────┴────────────────────────────┘


**New benchmarking circuits:** `mitiq.benchmarks` now contains a function `generate_random_clifford_t_circuit` which does what it says on the tin.
Special shoutout to new UF team member Farrokh Labib (farlab) for this contribution.

py
from mitiq.benchmarks import generate_random_clifford_t_circuit

clifft = generate_random_clifford_t_circuit(
num_qubits=2,
num_oneq_cliffords=5,
num_twoq_cliffords=5,
num_t_gates=5
)
print(clifft)
0: ──────────────S───T──────H───T───X───T───T─────────────
│ │ │ │ │
1: ───S───T──────────────X──────────────S──────────X───S───


The `Executor.run` method now supports a single circuit instance in addition to a list for ease of use when working with a single circuit.

diff
- executor.run([circuit])
+ executor.run(circuit)


**Faster Tests!** Working on Mitiq has never been easier to develop with a faster (by 36%) test suite.

📓 Documentation

This release contains quite a few documentation improvements, including

1. New workflow images to elucidate the workflow for for using the `mitiq.shadows` module (available [here](https://mitiq.readthedocs.io/en/stable/guide/shadows.html))
2. A reorganized API-doc which should be easier to navigate
3. General clean up of the CDR user guide pages

Commits

- Clarify CDR training docs regarding the use of a markov chain monte carlo (2130) [natestemen]
- Update workflow images in documentation (2034) [purva-thakre]
- 2115 pauli twirling callibration of expectation estimation shadow needs continue (2116) [bdg221]
- Add randomized clifford+T benchmarking circuits. (2118) [farlab]
- Frontend/Backend docs clean up (2124) [natestemen]
- Speed up tests using mocks (2126) [natestemen]
- resolve flaky mirror QV circuit test (2127) [natestemen + misty-w]
- Simplify expectation_estimation_shadow code (2113) [bdg221]
- Refactor calibration logs (2074) [kozhukalov]
- Organize API-doc (2104) [purva-thakre]
- add support for single circuit on exeuctor run method (2099) [emilianog-byte]

📦 Dependency updates

- Update qiskit-ibm-provider requirement from ~=0.7.2 to ~=0.7.3 (2122) [dependabot]
- Update cirq requirement from <1.3.0,>=1.0.0 to >=1.0.0,<1.4.0 (2107) [dependabot]
- Update pennylane requirement from ~=0.32.0 to ~=0.33.1 (2091) [dependabot]
- Update pennylane-qiskit requirement from ~=0.32.0 to ~=0.33.0 (2081) [dependabot]
- Bump stim/stimcirq from 1.12.0 to 1.12.1 (2106) [dependabot]
- Update amazon-braket-sdk requirement from ~=1.59.2 to ~=1.64.1 (2089 + 2094 + 2114 + 2123) [dependabot]
- Update scipy requirement from <=1.11.3,>=1.5.0 to >=1.5.0,<=1.11.4 (2095) [dependabot]

🧑‍💻 Dev Dependency updates

- Bump myst-nb from 0.17.1 to 1.0.0 (2090) [dependabot]
- Bump pandas from 2.1.2 to 2.1.3 (2093) [dependabot]
- Bump matplotlib from 3.8.0 to 3.8.1 (2084) [dependabot]
- Bump isort from 5.12.0 to 5.13.2 (2120 + 2125) [dependabot]
- Bump actions/setup-python from 4 to 5 (2112) [dependabot]

│ Scale method: fold_global │ Improvement factor: 0.5333 │ Improvement factor: 1.0309 │
├────────────────────────────────────┼────────────────────────────┼────────────────────────────┤
│ Technique: ZNE │ ✘ │ ✔ │
│ Factory: Linear │ Noisy error: 0.03 │ Noisy error: 1.0 │

([Full Changelog](https://github.com/unitaryfund/mitiq/compare/v0.43.0...v0.44.0))

Highlights

🚀 This release introduces the first version of the **Virtual Distillation** (VD) technique in Mitiq, which is now available for use!
This technique was prototyped and implemented by a team of students at the University of Amsterdam.
VD uses additional qubits to distill a purer version of the quantum state of interest.
The implementation is in its early stages so lacks support for all `QPROGRAM` types.
Currently only programs written in `cirq` are supported.
We welcome feedback and suggestions for improvement.

py
from mitiq import vd

vd.execute_with_vd(circuit, execute)
>>> np.array([0.5, 0.5]) [<Z_0>, <Z_1>] assuming the circuit acts on 2 qubits


We've also made further enhancements to the **Layerwise Richardson Extrapolation** (LRE) technique, including support for observables and the `mitiq.Executor` class.
`mitiq.lre` also has two new functions `mitiq.lre.construct_circuits` and `mitiq.lre.combine_results` that allow users to generate circuits and combine results in a more modular way (bringing this module in line with the other error mitigation techniques).
An example workflow for the two step application LRE is shown below:

py
from mitiq import lre

lre_circuits = lre.construct_circuits(circuit, degree, fold_multiplier)

results = execute(lre_circuits)

lre_result = lre.combine_results(results, circuit, degree, fold_multiplier)


🚨 Breaking Changes

For uniformity across modules within Mitiq we have renamed the folowing functions:
1. `mitiq.zne.scaled_circuits` -> `mitiq.zne.construct_circuits`
2. `mitiq.ddd.generate_circuits_with_ddd` -> `mitiq.ddd.construct_circuits`
3. `mitiq.pec.generate_sampled_circuits` -> `mitiq.pec.construct_circuits`

With this change, you will find the function `mitiq.<module>.construct_circuits` in all of ZNE, PEC, DDD, LRE, and VD.

We've also bound the version of `numpy` to be less than `2.0.0` due to some conflicts when using this latest major version.
We hope to support `numpy` 2.0.0 in a coming release.

---

If you're interested in error mitigation, check out our upcoming error resilience workshop in NYC!
WERQSHOP: Workshop on Error Resilience Quantum computing (https://werq.shop).

---


✨ Enhancements

- Modularization uniformity for ZNE, PEC, DDD, and LRE (2709) [bdg221]
- Add main API entry points for virtual distillation (2658) [Jegbrz]
- UFund => UFoundation (2706) [natestemen]
- allow list/tuple constructor in executor typehints (2700) [natestemen]
- Adding utility functions for Virtual Distillation. (2698) [FarLab]
- Auxilliary code for VD to apply a Bi matrix on a circuit (2650) [khknopp]
- Adding support for observables in LRE executors (2681) [Shivansh20128]
- Adding modularized function generate_circuits_with_ddd (2618) [Shivansh20128]
- Allow for Executor class and batched Executors for LRE (2676) [bdg221]
- Adding modularized function generate_sampled_circuits (2619) [Shivansh20128]
- Default scaling method in modularized ZNE function (2666) [purva-thakre]

📓 Documentation

- Adding docstrings to Observable class (2699) [Shivansh20128]
- add Virtual Distillation rfc to the contributing page and a new row in the error mitigation techniques in the readme. (2691) [FarLab]

📦 Dependency Updates

- bound numpy from above (2712) [natestemen]
- Update qiskit-ibm-runtime requirement from ~=0.36.1 to ~=0.37.0 (2693) [dependabot]
- Update qiskit-aer requirement from ~=0.15.1 to ~=0.17.0 (2694) [dependabot]
- Update amazon-braket-sdk requirement from ~=1.90.2 to ~=1.91.0 (2697) [dependabot]
- Update qiskit requirement from ~=1.4.1 to ~=1.4.2 (2696) [dependabot]
- Bump openfermion from 1.6.1 to 1.7.0 (2671) [dependabot]
- Update amazon-braket-sdk requirement from ~=1.69.0 to ~=1.90.2 (2690) [dependabot]
- Update qibo requirement from ~=0.2.15 to ~=0.2.16 (2689) [dependabot]
- Update qiskit-ibm-runtime requirement from ~=0.20.0 to ~=0.36.1 (2314) [dependabot]
- Update scipy requirement from <=1.14.1,>=1.10.1 to >=1.10.1,<=1.15.2 (2673) [dependabot]
- Update qiskit requirement from ~=1.3.1 to ~=1.4.1 (2685) [dependabot]
- Update pyquil requirement from ~=3.5.4 to ~=4.11.0 (2063) [dependabot]