From 16555851b6514a736c5c9d8e73de7da7fc9b6288 Mon Sep 17 00:00:00 2001 From: Prefetch Date: Thu, 20 Oct 2022 18:25:31 +0200 Subject: Migrate from 'jekyll-katex' to 'kramdown-math-sskatex' --- source/know/concept/dirac-notation/index.md | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'source/know/concept/dirac-notation') diff --git a/source/know/concept/dirac-notation/index.md b/source/know/concept/dirac-notation/index.md index 8861505..46cc325 100644 --- a/source/know/concept/dirac-notation/index.md +++ b/source/know/concept/dirac-notation/index.md @@ -12,16 +12,16 @@ layout: "concept" without needing to worry about the space's representation. It is basically the *lingua franca* of quantum mechanics. -In Dirac notation there are **kets** $\Ket{V}$ from the Hilbert space -$\mathbb{H}$ and **bras** $\Bra{V}$ from a dual $\mathbb{H}'$ of the +In Dirac notation there are **kets** $$\Ket{V}$$ from the Hilbert space +$$\mathbb{H}$$ and **bras** $$\Bra{V}$$ from a dual $$\mathbb{H}'$$ of the former. Crucially, the bras and kets are from different Hilbert spaces and therefore cannot be added, but every bra has a corresponding ket and vice versa. Bras and kets can be combined in two ways: the **inner product** -$\Inprod{V}{W}$, which returns a scalar, and the **outer product** -$\Ket{V} \Bra{W}$, which returns a mapping $\hat{L}$ from kets $\Ket{V}$ -to other kets $\Ket{V'}$, i.e. a linear operator. Recall that the +$$\Inprod{V}{W}$$, which returns a scalar, and the **outer product** +$$\Ket{V} \Bra{W}$$, which returns a mapping $$\hat{L}$$ from kets $$\Ket{V}$$ +to other kets $$\Ket{V'}$$, i.e. a linear operator. Recall that the Hilbert inner product must satisfy: $$\begin{aligned} @@ -29,7 +29,7 @@ $$\begin{aligned} \end{aligned}$$ So far, nothing has been said about the actual representation of bras or -kets. If we represent kets as $N$-dimensional columns vectors, the +kets. If we represent kets as $$N$$-dimensional columns vectors, the corresponding bras are given by the kets' adjoints, i.e. their transpose conjugates: @@ -45,7 +45,7 @@ $$\begin{aligned} \end{bmatrix} \end{aligned}$$ -The inner product $\Inprod{V}{W}$ is then just the familiar dot product $V \cdot W$: +The inner product $$\Inprod{V}{W}$$ is then just the familiar dot product $$V \cdot W$$: $$\begin{gathered} \Inprod{V}{W} @@ -60,7 +60,7 @@ $$\begin{gathered} = v_1^* w_1 + ... + v_N^* w_N \end{gathered}$$ -Meanwhile, the outer product $\Ket{V} \Bra{W}$ creates an $N \cross N$ matrix: +Meanwhile, the outer product $$\Ket{V} \Bra{W}$$ creates an $$N \cross N$$ matrix: $$\begin{gathered} \Ket{V} \Bra{W} @@ -80,9 +80,9 @@ $$\begin{gathered} \end{bmatrix} \end{gathered}$$ -If the kets are instead represented by functions $f(x)$ of -$x \in [a, b]$, then the bras represent *functionals* $F[u(x)]$ which -take an unknown function $u(x)$ as an argument and turn it into a scalar +If the kets are instead represented by functions $$f(x)$$ of +$$x \in [a, b]$$, then the bras represent *functionals* $$F[u(x)]$$ which +take an unknown function $$u(x)$$ as an argument and turn it into a scalar using integration: $$\begin{aligned} -- cgit v1.2.3