# Notions from Linear Algebra and Bra-Ket Notation

• Rainer Dick
Chapter
Part of the Graduate Texts in Physics book series (GTP)

## Abstract

The Schrödinger equation (1.14) is linear in the wave function ψ(x, t). This implies that for any set of solutions ψ1(x, t), $${\psi }_{2}(x,t),\ldots$$, any linear combination $$\psi (x,t) = {C}_{1}{\psi }_{1}(x,t) + {C}_{2}{\psi }_{2}(x,t) + \ldots$$ with complex coefficients C n is also a solution. The set of solutions of equation (1.14) for fixed potential V will therefore have the structure of a complex vector space, and we can think of the wave function ψ(x, t) as a particular vector in this vector space. Furthermore, we can map this vector bijectively into different, but equivalent representations where the wave function depends on different variables. An example of this is Fourier transformation (2.5) into a wave function which depends on a wave vector k,
$$\psi (k,t) = \frac{1} {{\sqrt{2\pi }}^{3}} \int \nolimits \nolimits \!{d}^{3}x\,\exp \!\left (-\mathrm{i}k \cdot x\right )\psi (x,t).$$

## Keywords

Wave Function Tensor Product Basis Vector Linear Algebra Dual Basis
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

## Authors and Affiliations

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