quantum-computing
6 lessons tagged quantum-computing: free, quiz-checked micro-lessons.
Post-quantum cryptography: lattices, codes, and the migration
What cryptographic schemes Shor's algorithm threatens, what post-quantum schemes replace them, the math behind lattice-based cryptography, the NIST standardization process and its outputs, and the operational mechanics of a real-world cryptographic migration.
Algorithms where quantum beats classical (and where it doesn't)
Shor, Grover, Hamiltonian simulation, HHL — the catalog of known quantum-algorithmic speedups, what 'speedup' precisely means in each case, and the structural reasons most problems do not gain exponential advantage.
Errors, syndromes, and the surface code
Why classical error correction does not directly transfer to qubits, how stabilizer codes and syndrome measurement work around the no-cloning constraint, the surface code as the leading approach, and the math of physical-to-logical qubit overhead.
Hardware approaches: superconducting, ion, photonic, atomic, spin
Six families of physical qubit implementations and the engineering trade-offs that distinguish them — coherence time, gate time and fidelity, scalability, and control complexity. The numbers behind 'which is best' depend on which metric you care about.
Entanglement, gates, and the circuit model
What entanglement is mathematically, how Bell states are built from Hadamard and CNOT, how quantum circuits compose, and why measurement on entangled subsystems looks correlated regardless of separation.
Superposition and the qubit
The mathematical object behind a qubit — a complex unit vector in a two-dimensional Hilbert space — and why measurement collapses superposition. The structural difference between a quantum state and a classical bit, expressed in math.