Quantum superposition
If a quantum system can be in state A and can be in state B, then it can also be in a combination of both, called a superposition. This is not ignorance about which state it is really in. The combination produces interference effects that neither A alone nor B alone would produce, and those effects are measured. When the system is measured, one definite outcome appears, with probabilities set by how much of each state the combination contains.
Why it matters
Superposition is what makes quantum computing and quantum interference possible, and it is the feature that generates every interpretive puzzle in the subject.
Also written: superposition
Where it comes up
Read about Quantum superposition on Wikipedia
Sources
- Quantum superposition English Wikipedia
- Quantum Mechanics Stanford Encyclopedia of Philosophy
