[WIP] Add save_expval to extended_stabilizer - Githubissues

Qiskit / qiskit-aer

Aer is a high performance simulator for quantum circuits that includes noise models

https://qiskit.github.io/qiskit-aer/

Apache License 2.0

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[WIP] Add save_expval to extended_stabilizer #2161

Open doichanj opened 3 weeks ago

doichanj commented 3 weeks ago

Summary

This PR adds (enables) save_expvaland save_expval_var to extended_stabilizer requested by #2121

Details and comments

save_expvaland save_expval_var in extended_stabilizer were disabled because there were bug in expectation values calculation. I found 3 issues:

save_expval_var was not included in State::check_measurement_opt
Phase for Y gate was not updated
The same random number generator was used in the parallel loop in Runner::norm_estimation

Now it works for cliffords cases, but it still does not work for non-cliffords cases