Born rule in quantum mechanics

E75605

The Born rule in quantum mechanics is the fundamental postulate that connects a system’s wavefunction to experimentally observed probabilities by stating that measurement outcomes occur with probabilities given by the squared magnitude of the wavefunction’s amplitudes.


Statements (50)
Predicate Object
instanceOf postulate of quantum mechanics
probability rule
alsoKnownAs Born statistical interpretation
Born’s rule
appliesTo positive operator-valued measures
projective measurements
quantum measurement outcomes
assumes normalized wavefunction
concerns outcome statistics of repeated measurements
connects Hilbert space formalism to experimental statistics
domain Hilbert space of quantum states
field quantum mechanics
formalExpression P(a) = ⟨ψ|Π_a|ψ⟩ where Π_a is the projector onto the eigenspace of outcome a
P(i) = |c_i|^2 for a state |ψ⟩ = Σ_i c_i |i⟩
implies interference patterns in double-slit experiments
probabilities depend on relative phases of amplitudes
total probability equals one
isAssumedIn standard quantum theory
isAssumedRatherThanDerivedIn standard textbook formulations
isCompatibleWith unitary time evolution between measurements
isDebatedIn interpretations of quantum mechanics
isDerivedInSomeApproachesFrom decision-theoretic axioms
envariance arguments
symmetry principles
typicality arguments
isEssentialFor empirical predictions of quantum mechanics
isFoundationFor Bayesian approaches to quantum probabilities
Born measure on projective Hilbert space
frequentist interpretation of quantum probabilities
quantum decision theory
isPostulateIn Copenhagen interpretation of quantum mechanics
isUsedIn Born approximation in scattering
particle physics experiments
quantum computing
quantum information theory
quantum optics
quantum state tomography
quantum statistical mechanics
scattering theory
spectroscopy
namedAfter Max Born
relates measurement probabilities
wavefunction
requires complex-valued wavefunction or state vector
role gives operational meaning to the wavefunction
links quantum states to observable probabilities
statesThat the probability of obtaining a measurement outcome is given by the squared modulus of the corresponding amplitude in the wavefunction
usesQuantity probability amplitude
squared magnitude of the wavefunction
yearProposed 1926

Referenced by (5)
Subject (surface form when different) Predicate
Born rule ("Born’s rule")
alsoKnownAs
Copenhagen interpretation of quantum mechanics ("Born rule")
coreConcept
Copenhagen interpretation of quantum mechanics ("Born's probabilistic interpretation")
influencedBy
Max Born
knownFor
von Neumann measurement scheme ("Born rule for outcome probabilities")
postulates

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