Boolean circuits as gates

[alexanderivrii]

Summary

Part of #13046. Adds the following Gate classes in addition to existing QuantumCircuit classes:

• AndGate for AND
• OrGate for OR
• BitwiseXorGate for XOR
• InnerProductGate for InnerProduct

Details and comments

To be honest, the difference between an AndGate gate and an AND quantum circuit is rather small. In addition to the general consistency pursued by #13046, it might be just a tiny bit more ergonomic to type
qc.append(AndGate(5), [0, 1, 2, 3, 4, 5]) rather than qc.append(AND(5).to_gate(), [0, 1, 2, 3, 4, 5]), and the first circuit has one less level of nestedness than the second (in the former case it takes one call to decompose to see the definition circuit, and in the latter case - two). This applies to all 4 gates.

Actually, another benefit for AndGate and OrGate is that as their definitions are built on top of MCX gates, we are able to use all the synthesis methods that leverage ancilla qubits via the "mcx" plugin mechanism.

[qiskit-bot]

One or more of the following people are relevant to this code:

• @Cryoris
• @Qiskit/terra-core
• @ajavadia

[coveralls]

Pull Request Test Coverage Report for Build 11595891469

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 91 of 98 (92.86%) changed or added relevant lines in 6 files are covered.
• 12 unchanged lines in 5 files lost coverage.
• Overall coverage increased (+0.02%) to 88.711%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit/circuit/library/boolean_logic/inner_product.py	15	16	93.75%
qiskit/circuit/library/boolean_logic/quantum_and.py	24	25	96.0%
qiskit/circuit/library/boolean_logic/quantum_or.py	25	26	96.15%
qiskit/circuit/library/boolean_logic/quantum_xor.py	22	26	84.62%

Files with Coverage Reduction	New Missed Lines	%
qiskit/circuit/library/iqp.py	1	96.15%
crates/accelerate/src/unitary_synthesis.rs	1	92.2%
crates/qasm2/src/expr.rs	1	94.02%
crates/qasm2/src/lex.rs	3	92.48%
crates/qasm2/src/parse.rs	6	97.62%

Totals
Change from base Build 11590598875:	0.02%
Covered Lines:	75593
Relevant Lines:	85213

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💛 - Coveralls

[Cryoris]

Thanks for adding this! I left some small comments below 🙂

[Cryoris]

LGTM, thank you!