Amplitude
A complex number whose squared magnitude gives the probability of a measurement outcome.
Reference
Glossary of quantum technology terms
Concise definitions for quantum computing, hardware, error correction and security terminology.
Coherence time
How long a qubit retains usable phase information before environmental interaction degrades it.
Entanglement
A joint state that cannot be written as an independent state for each subsystem.
Fault tolerance
Reliable computation despite faulty components by encoding and repairing errors continuously.
Fidelity
How closely an achieved operation or state matches the intended one.
Logical qubit
An error-protected qubit encoded across many physical qubits.
Post-quantum cryptography
Classical cryptographic schemes designed to resist large-scale quantum attacks.
Qubit
The basic unit of quantum information, described by amplitudes over two basis states.
Superposition
A state described by multiple basis amplitudes, enabling interference between computational paths.