1.2 KiB
Vectors to describe quantum states can get tedious really quick, so we introduce a new notation.
We can rewrite a quantum state in the following way:
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To represent the vector e_i as its classical possibility we use \ket{} .
For a classical possibility x, which is the i-th possibility represented by e_i we use:
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Example:
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Also we have 2 special cases:
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\ket{+} = \begin{pmatrix} \frac{1}{\sqrt{2}} \\ \frac{1}{\sqrt{2}} \end{pmatrix}
\ket{-} = \begin{pmatrix} \frac{1}{\sqrt{2}} \\ -\frac{1}{\sqrt{2}} \end{pmatrix}
The Teleportation example from Quantum Circuits with ket notation:
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Bra and Braket notation
Additionally to ket notation, bra notation, \bra{} denotes the conjugate transpose of \ket{}:
\bra{\psi} := \ket{\psi}^\dagger
Example:
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Combined, we get the Braket notation \braket{\psi||\phi}
Example:
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