Extended the gate set for pauli twirling

[d-bharadwaj]

This pull request enhances the pauli_twirling utility by adding support for more two-qubit gates and refactoring the code to be more modular. It also includes comprehensive tests for the newly supported gates.

Enhancements to pauli_twirling utility:

• qiskit_research/utils/pauli_twirling.py: Added support for multiple two-qubit gates by importing additional gate classes and defining corresponding gate instances.
• qiskit_research/utils/pauli_twirling.py: Introduced the create_pauli_twirling_sets function to dynamically generate Pauli twirling sets for any two-qubit gate, and updated the TWIRL_GATES dictionary to use this function.

Testing enhancements:

• test/utils/test_pauli_twirling.py: Added imports for the new gate classes to be tested.
• test/utils/test_pauli_twirling.py: Added test cases for each newly supported two-qubit gate to verify correct implementation of Pauli twirling.

Additionally, I have run the tests using tox locally and have added some more tests for the utilities introduced. Also thanks to this repo that helped me out with this. This enhancement was discussed in Issue #120, where I brought it up, and @kevinsung requested me to open a pull request.

[CLAassistant]

All committers have signed the CLA.

[coveralls]

Pull Request Test Coverage Report for Build 11619932235

Details

• 41 of 42 (97.62%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+1.2%) to 68.32%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit_research/utils/pauli_twirling.py	41	42	97.62%

Totals
Change from base Build 11055740630:	1.2%
Covered Lines:	675
Relevant Lines:	988

---

💛 - Coveralls

[kevinsung]

Thank you for the contribution, this is very useful!

[kevinsung]

Thank you!

[d-bharadwaj]

Thank you!

Of course!