Mitiq is a Python toolkit for implementing error mitigation techniques on quantum computers.

Current quantum computers are noisy due to interactions with the environment, imperfect gate applications, state preparation and measurement errors, etc. Error mitigation seeks to reduce these effects at the software level by compiling quantum programs in clever ways.

Want to know more? Check out our documentation and chat with us on Discord.

Do you use near-term quantum hardware? Have you tried Mitiq? Either way, take our survey and help make Mitiq better! bit.ly/mitiq-survey

Quickstart

Installation

pip install mitiq

Example

Define a function which inputs a circuit and returns an expectation value you want to compute, then use Mitiq to mitigate errors.

import cirq
from mitiq import zne, benchmarks


def execute(circuit: cirq.Circuit, noise_level: float = 0.001) -> float:
    """Returns Tr[ρ |0⟩⟨0|] where ρ is the state prepared by the circuit with depolarizing noise."""
    noisy_circuit = circuit.with_noise(cirq.depolarize(p=noise_level))
    return cirq.DensityMatrixSimulator().simulate(noisy_circuit).final_density_matrix[0, 0].real


circuit: cirq.Circuit = benchmarks.generate_rb_circuits(n_qubits=1, num_cliffords=50)[0]

true_value = execute(circuit, noise_level=0.0)       # Ideal quantum computer.
noisy_value = execute(circuit)                       # Noisy quantum computer.
zne_value = zne.execute_with_zne(circuit, execute)   # Noisy quantum computer + Mitiq.

print(f"Error (w/o  Mitiq): %0.4f" %abs((true_value - noisy_value) / true_value))
print(f"Error (with Mitiq): %0.4f" %abs((true_value - zne_value) / true_value))

Sample output:

Error (w/o  Mitiq): 0.0688
Error (with Mitiq): 0.0002

See our guides and examples for more explanation, techniques, and benchmarks. The examples and other notebooks can be run interactively on the cloud with mybinder.org.

Quick Tour

Error mitigation techniques

See our roadmap for additional candidate techniques to implement. If there is a technique you are looking for, please file a feature request.

Interface

We refer to any programming language you can write quantum circuits in as a frontend, and any quantum computer / simulator you can simulate circuits in as a backend.

Supported frontends

Cirq	Qiskit	pyQuil	Braket	PennyLane

Note: Cirq is a core requirement of Mitiq and is installed when you pip install mitiq.

Supported backends

You can use Mitiq with any backend you have access to that can interface with supported frontends.

Citing Mitiq

If you use Mitiq in your research, please reference the Mitiq preprint (bibtex). A list of papers citing Mitiq can be found on Google Scholar / Semantic Scholar.

License

GNU GPL v.3.0.

Contributing

We welcome contributions to Mitiq including bug fixes, feature requests, etc. To get started, check out our contribution guidelines and/or documentation guidelines. An up-to-date list of contributors can be found here and below.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

Yash-10 ⚠️ 💻	Laurent AJDNIK 📖	Tianyi Hao 💻 🐛	Brian Lui 💻 🐛	Cole Kissane 💻 🐛	Michał Stęchły 💻	Kunal Marwaha 📖
k-m-schultz 💡	Bobin Mathew 📖	LogMoss 📖 🐛	DSamuel1 💡 💻	sid1993 💻 🐛	Yousef Hindy 💻 ⚠️ 📖	Mohamed El Mandouh 💻 ⚠️ 📖
Aaron Robertson 💡 ⚠️ 🐛	Ashish Panigrahi 📖	Maxime Tremblay 💻 📖 🤔	Andre 📖 ⚠️	Purva Thakre 📖 🚇 💻 🤔	Peter Karalekas 🚧 💻 📖 🚇 🤔	Sarah Kaiser 🚧 💻 📖 🚇 🤔
Andrea Mari 🚧 💻 📖 🚇 🤔	Will Zeng 🚧 💻 📖 🚇 🤔	Nathan Shammah 🚧 💻 📖 🚇 🤔	Ryan LaRose 🚧 💻 📖 🚇 🤔	francespoblete 🎨	Misty-W 💻 💡	AkashNarayanan B 🚇

This project follows the all-contributors specification. Contributions of any kind welcome!