Inspiration
Quantum computing presents unprecedented capabilities for communication security and computational problem-solving. We were inspired to explore the foundational principles of quantum information science—from entanglement-based cryptography with the Ekert91 protocol to algorithmic quantum search and variational algorithms for molecular chemistry.
What it does
Our project tackles core challenges within quantum computing using Qiskit:
- E91 Quantum Key Distribution (QKD): Implemented Ekert's entanglement-based protocol using Bell pairs. It performs random basis selection, key sifting, quantum bit error rate (QBER) estimation, and evaluates Bell/CHSH inequality violations to detect intercept-resend eavesdropping attacks versus channel noise.
- Grover Search under Noise: Benchmarked quantum database search using oracle construction and diffusion operators, evaluating algorithm fidelity and success probabilities under bit-flip and depolarizing noise models against classical bounds.
- Variational Quantum Eigensolver (VQE): Explored molecular ground-state energy estimation (LiH) with Jordan-Wigner Hamiltonian mapping, symmetry reductions, and parameterized ansatz circuits under realistic shot and gate budgets.
How we built it
- Framework: Implemented using IBM's Qiskit SDK (v2.x) and Qiskit Aer for realistic noisy statevector and shot-based quantum circuit simulations.
- Analysis & Verification: Formulated theoretical predictions, statistical error bounds, and CHSH correlation metrics with NumPy and SciPy.
- Visualization: Plotted correlation curves, noise thresholds, and fidelity sweeps using Matplotlib.
Challenges we ran into
- Managing shot noise and finite measurement statistics while reliably distinguishing eavesdropper intervention from physical depolarizing noise in the E91 protocol.
- Balancing circuit depth and two-qubit gate counts within strict resource budgets.
Accomplishments that we're proud of
- Verified Bell's inequality violation ($S > 2$) showing non-classical correlations in safe channels.
- Successfully detected intercept-resend attacks through both CHSH degradation and elevated QBER.
- Built modular, reproducible Qiskit implementations designed for automated testing.
What we learned
- Deep practical intuition on how quantum entanglement enables provable security in quantum communications.
- Techniques for noisy quantum circuit simulation and error mitigation in NISQ-era algorithms.
