Quantum mechanics describes how matter behaves at atomic and subatomic scales, where particles can act unlike anything predicted by classical physics. Its ideas provide the foundation for understanding quantum computers and their significance to cryptography. section 14.1 section 14.1.1
The key ideas are:
- Particles can behave like waves, allowing waves to superpose, reinforce one another, or cancel briefly. section 14.1.1
- A particle can occupy quantum superposition: an electron, for example, may be described as spinning up and down before measurement. section 14.1.1
- Measurement collapses the superposition into one observable state; for two equally likely spin states, each has a 50% chance of appearing. section 14.1.1
- Quantum computers use this behavior in qubits, which can represent 0 and 1 in superposition rather than holding only one classical bit value. section 14.1.1
