2.NounA column vector, in Hilbert space, especially as representing the state of a quantum mechanical system; the complex conjugate transpose of a bra (a row vector); a ket vector. Symbolised by |...〉."A particular ket, say
|
A
⟩
{\displaystyle |A\rangle }
, might be represented by a particular column vector. Its corresponding bra,
⟨
A
|
{\displaystyle \langle A|}
, would then be represented by the row vector which is the transpose conjugate of that column vector."