bra-ket
English edit
Etymology edit
Concatenation of the terms bra and ket, which were introduced in 1939[1] and in turn derive from the splitting of the English word bracket.
Noun edit
- (physics) The scalar product of two vectors (and optionally an operator), in Hilbert space, where the left (row) vector is a bra and the right (column) vector is a ket. Symbolised by ⟨...|...⟩ (bra and ket only) or ⟨...|...|...⟩ (bra, operator, ket).