Hotfix for rabi length following #744

[andrea-pasquale]

In #744 I forgot to update the rabi length protocol.

EDIT: Improved fit for rabi length with probabilities.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.
• Compatibility with Qibo modules (Please edit this section if the current pull request is not compatible with the following branches).
  • Qibo: master
  • Qibolab: main
  • Qibolab_platforms_qrc: main

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.89%. Comparing base (1026f4f) to head (6cd7185).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #754   +/-   ##
=======================================
  Coverage   96.88%   96.89%           
=======================================
  Files         108      108           
  Lines        7491     7508   +17     
=======================================
+ Hits         7258     7275   +17     
  Misses        233      233           

Flag	Coverage Δ
unittests	96.89% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
.../qibocal/protocols/characterization/rabi/length.py	97.87% <100.00%> (-0.05%)	⬇️
...l/protocols/characterization/rabi/length_signal.py	97.93% <100.00%> (+0.50%)	⬆️

[stavros11]

Thanks @andrea-pasquale, I believe it fixes the fitting:
Before: http://login.qrccluster.com:9000/0dk2ahd8RjuAd1tPe_QUHQ==
After: http://login.qrccluster.com:9000/r3dZGTOaRHu21mr0RrNe7A==
(I guess qubit 2 fails in both cases because the signal is not really sinusoidal).

[andrea-pasquale]

Thanks @andrea-pasquale, I believe it fixes the fitting:

Before: http://login.qrccluster.com:9000/0dk2ahd8RjuAd1tPe_QUHQ==

After: http://login.qrccluster.com:9000/r3dZGTOaRHu21mr0RrNe7A==

(I guess qubit 2 fails in both cases because the signal is not really sinusoidal).

Thanks @stavros11. The fix was just to show correctly the fit in the report. I did not touch or improve the performance of the fit. I can have a closer look at qubit 2 before merging.

[stavros11]

Thanks @stavros11. The fix was just to show correctly the fit in the report. I did not touch or improve the performance of the fit. I can have a closer look at qubit 2 before merging.

Well, the minima are clearly more flat than a sinusoidal, so I wouldn't blame the fit for failing in that case. There should be something wrong with the qubit/calibration parameters. We were just discussing with @rodolfocarobene why this happens but we don't have any idea. The insteresting thing is that this is the qubit that has 97% assignment fidelity...

[andrea-pasquale]

Since you have 97% fidelity you could try to run rabi length with probabilities.

[stavros11]

Since you have 97% fidelity you could try to run rabi length with probabilities.

Indeed, looks better but the fit still fails: http://login.qrccluster.com:9000/WfsuyLv_QmKTKPthroPbRQ==

[andrea-pasquale]

Since you have 97% fidelity you could try to run rabi length with probabilities.

Indeed, looks better but the fit still fails: http://login.qrccluster.com:9000/WfsuyLv_QmKTKPthroPbRQ==

Yeah, there was a problem with the fit. Should be fixed by 6cd7185. Feel free to retry now @stavros11.

It turns out that just by normalizing the x axis everything seems to work...

[stavros11]

It works for me as well, thanks.