What is Quantum?
A clear, technically honest primer. No hype, no over-simplification — the conceptual model security and engineering professionals actually need.
Qubit
A quantum bit. Unlike a classical bit (0 or 1), a qubit can hold a continuous probability amplitude across both states until measured. Physical implementations include superconducting circuits, trapped ions, neutral atoms, and photonic modes.
Superposition
A qubit can exist in a weighted combination of |0⟩ and |1⟩ simultaneously. n qubits can represent 2ⁿ states at once — the structural source of quantum's parallelism.
Entanglement
Two or more qubits whose states cannot be described independently. Measuring one instantly determines the others. This is the engine behind quantum communication and most useful quantum algorithms.
Quantum Advantage
The point at which a quantum processor solves a problem faster than the best classical algorithm. For some workloads (factoring, simulation) the speedup is exponential. For others, only modest. Knowing which is which is the entire game.
Interactive Qubit
Tap to cycle through basis states and a superposition. The dot is the Bloch-sphere projection of the state vector.