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Physlib.QuantumMechanics.OneDimension.HilbertSpace.PositionStates

2 declarations

definition

Position state δx\delta_x as a tempered distribution

#positionState

For a given position xRx \in \mathbb{R}, the position state is defined as the continuous linear functional on the Schwartz space S(R,C)\mathcal{S}(\mathbb{R}, \mathbb{C}) that maps a function ψ\psi to its value at xx, i.e., ψ(x)\psi(x). This functional is the Dirac delta distribution δx\delta_x, viewed as an element of the space of tempered distributions S(R,C)\mathcal{S}'(\mathbb{R}, \mathbb{C}).

theorem

positionState(x)(ψ)=ψ(x)\text{positionState}(x)(\psi) = \psi(x)

#positionState_apply

For any position xRx \in \mathbb{R} and any Schwartz function ψS(R,C)\psi \in \mathcal{S}(\mathbb{R}, \mathbb{C}), the application of the position state functional at xx to ψ\psi is equal to the value of the function at xx, i.e., positionState(x)(ψ)=ψ(x)\text{positionState}(x)(\psi) = \psi(x). This identifies the position state as the Dirac delta distribution δx\delta_x.