# Quantum Error Mitigation

From the QuTiP 4.5 release, the qutip.qip module now contains the noisy quantum circuit simulator (which was a GSoC project) providing enhanced features for a pulse-level description of quantum circuits and noise models. A new class Processor and several subclasses are added to represent different platforms for quantum computing. They can transfer a quantum circuit into the corresponding control sequence and simulate the dynamics with QuTiP solvers. Different noise models can be added to qutip.qip.noise to simulate noise in a quantum device.

This module is still young and many features can be improved, including new device models, new noise models and integration with the existing general framework for quantum circuits (qutip.qip.circuit). There are also possible applications such as error mitigation techniques ([1], [2], [3]).

The tutorial notebooks can be found in the Quantum information processing section of https://qutip.org/qutip-tutorials/index-v5.html. A recent presentation on the FOSDEM conference may help you get an overview (https://fosdem.org/2020/schedule/event/quantum_qutip/). See also the Github Project page for a collection of related issues and ongoing Pull Requests.

## Expected outcomes

- Make an overview of existing libraries and features in error mitigation, similarly to a literature survey for a research article, but for a code project (starting from Refs. [4], [5]). This is done in order to best integrate the features in QuTiP with existing libraries and avoid reinventing the wheel.

- Features to perform error mitigation techniques in QuTiP, such as zero-noise extrapolation by pulse stretching.

- Tutorials implementing basic quantum error mitigation protocols

- Possible integration with Mitiq [6]

## Skills

- Background in quantum physics and quantum circuits.

- Git, python and familiarity with the Python scientific computing stack

## Difficulty

- Medium

## Mentors

- Nathan Shammah (nathan.shammah@gmail.com)

- Alex Pitchford (alex.pitchford@gmail.com)

- Eric Giguère (eric.giguere@usherbrooke.ca)

- Neill Lambert (nwlambert@gmail.com)

- Boxi Li (etamin1201@gmail.com) [QuTiP GSoC 2019 graduate]

## References

[1]

Kristan Temme, Sergey Bravyi, Jay M. Gambetta, Error mitigation for short-depth quantum circuits, Phys. Rev. Lett. 119, 180509 (2017)

[2]

Abhinav Kandala, Kristan Temme, Antonio D. Corcoles, Antonio Mezzacapo, Jerry M. Chow, Jay M. Gambetta, Extending the computational reach of a noisy superconducting quantum processor, Nature 567, 491 (2019)

[3]

19. Endo, S.C. Benjamin, Y. Li, Practical quantum error mitigation for near-future applications, Physical Review X 8, 031027 (2018)

[4]

Boxi Li’s blog on the GSoC 2019 project on pulse-level control, https://gsoc2019-boxili.blogspot.com/

[5]

Video of a recent talk on the GSoC 2019 project, https://fosdem.org/2020/schedule/event/quantum_qutip/

[6]

Mitiq