Established physics · Bridge definitions
Quantum foundations: useful words
amplitude
A generally complex number used to predict a measurement outcome. Its magnitude and phase matter; its squared magnitude gives an outcome probability in a normalized outcome basis.
Bell test
An experiment comparing joint correlations against a Bell inequality, testing the assumptions behind that bound with suitable setting choices and experimental controls.
Born rule
The rule assigning measurement probabilities from a quantum state. For an ideal outcome basis, each probability is the squared magnitude of its normalized amplitude.
decoherence
Suppression of observable interference between alternatives through their correlations with other degrees of freedom, such as an environment.
entanglement
A joint quantum state that cannot be represented as a mixture of independent product states of its parts. It can produce correlations beyond those of separable states.
interference
The change in predicted probabilities caused by adding coherent amplitudes before taking their squared magnitude.
marginal probability
A local probability obtained by summing joint probabilities over the other system’s possible outcomes.
measurement
A physical interaction that correlates a system with an outcome record. Conscious awareness is not a required ingredient.
no-signaling
The inability to alter a remote observer’s unconditioned outcome probabilities using local operations alone. Revealing selected correlations still needs ordinary communication.
phase
The angular part of a complex amplitude. Relative phase changes how coherent alternatives reinforce or cancel.
proper time
The elapsed time measured by an ideal clock along its path through spacetime. This established clock quantity differs from TRQC’s proposed premetric dependency order.
superposition
A quantum state formed by a linear combination of alternatives. Its interference effects depend on their amplitudes and on the measurement being made.