QvC: Quantum vs Classical

Inspiration

Quantum computing is fascinating but abstract. I wanted to demystify it by directly comparing quantum gates with their classical equivalents. Making quantum behavior tangible alongside classical logic helps bridge the gap between theory and practice.

What it does

QvC simulates quantum and classical circuits side-by-side, applying the same logical gates where possible. It shows initial and final states, highlighting where quantum mechanics outperforms or differs from classical logic—especially for superposition and entanglement gates.

How we built it

Built in modular C++: QuantumCircuit and QuantumRegister handle quantum states and gates. ClassicalCircuit and ClassicalRegister mimic classical logic. ComparisonRunner runs paired gate tests with clear outputs. Supports single, two, and multi-qubit gates, including controlled unitary gates. Implements mid-circuit measurements and conditional gate execution.

Challenges we ran into

Correctly implementing controlled gates with multiple qubits and keeping indexing consistent. Managing mid-circuit measurement without corrupting the quantum state. Synchronizing classical conditional logic with probabilistic quantum outcomes. Designing intuitive output for clear quantum vs classical comparison.

Accomplishments that we're proud of

Full support for key quantum gates (X, Y, Z, H, S, T, CNOT, CZ, Toffoli). Successfully simulating classical logic conditionals alongside quantum gates. Demonstrating multi-qubit controlled gates (CU) with arbitrary single-qubit unitary gates. Providing an easy-to-understand comparison framework that educates and inspires.

What we learned

Deepened understanding of quantum gate mechanics and classical logic equivalence. Practical experience with quantum state vectors and complex matrix operations. Challenges of combining deterministic classical logic with quantum probabilistic states. The importance of clear, user-friendly output to communicate complex ideas.

What's next for QvC: Quantum vs Classical

Expand to include noise modeling and error correction simulation. Add visualization of quantum states and measurement probabilities. Integrate real quantum hardware backends for hybrid classical-quantum workflows. Develop educational tools around gate comparisons for students and enthusiasts.

Built With

• c++