Interleaved Randomized Benchmarking of gates with delays

itoko commented 2 years ago

Description

This project aims to investigate what happens in idling of qubits by conducting Interleaved Randomized Benchmarking (InterleavedRB) of gates with delay instructions using qiskit-experiment (c.f. qiskit-experiments/tutorials).

For example, we may examine how much the spectator qubit (q2) affects CNOT gate (on q0 and q1) fidelity by 3-qubit InterleavedRB of CNOT(q0,q1)+Delay(q2). And investigating if the fidelity can be estimated by the results from the normal 2-qubit InterleavedRB of CNOT(q1, q2) and 1-qubit InterleavedRB of Delay(q2).

The above is just an example. If you think of more interesting experimental scenario, let's pursue it!

Unfortunately, the current InterleavedRB has no full capability to conduct complicated experiments like the above experiment. So you'll have to upgrade it so that you can

interleave Delay instructions
create RB circuits without changing qubit layout during Clifford operations
compare multiple interleaved RB curves with the reference RB curve etc.

Deliverables

A jupyter notebook investigating the results of RB of gates with delays. Advanced: Pull requests to enhance the RB module in qiskit-experiments.

Mentors details

Mentor
- Name: Toshinari Itoko
- GitHub ID: @itoko-san
- What they do: Qiskit developer (Terra/Aer), Researcher (circuit optimization/noise modeling)

Number of mentees

1 or 2

Type of mentees

Required:
- Interest in Randomized benchmarking and qiskit-experiments
- Python basics (including jupyter notebook)
Nice to have:
- Good knowledge of Qiskit transpiler would be helpful

gunchamalik commented 2 years ago

@itoko I am interested. I have basic knowledge of python and transpiler.

bicycle315 commented 2 years ago

I worked on qiskit experiment rb part on last metorship project. I want to keep dive in to this project!

bicycle315 commented 2 years ago

IRB with Delay.pdf

bicycle315 commented 2 years ago

Support dealy IRB with changed code

Interleaved benchmarking module in qiskit-experiments supported interleaving gates and quantumcircuit but not instruction such as delay. We fixed code to interleave delay as instruction.

made a development environment and install qiskit-experiment, qiskit-terra in editable mode
write a testcode to confirm the existing qiskit-experiments fails interleaving delay element and quantumcircuit with delay with unittest
fix the code to make 'delay' regarded as instruction
unittest show the fixed code works well -> make a PR https://github.com/Qiskit/qiskit-experiments/pull/776

Why Delay??

With the new delay element, we want to check how well the system keep the qubit state especially when there is no operation. When delay IRB is run on more than 3 qubit, the effect of spectator qubit can also be recognized. Delay can take an arbitrary duration than I Gate which depends on backend properties. Finally, we can evaluate how well the theory explains the real world by comparing the infidelity of delay which is an experimental value excluding gate dependent error and coherence limited EPG(error per gate) which is a theoretical one .