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Bra–ket notation


In quantum mechanics, bra–ket notation is a standard notation for describing quantum states. The notation uses angle brackets ("", and "") and vertical bars (""). It can also be used to denote abstract vectors and linear functionals in mathematics. In such terms, the scalar product, or action of a linear functional on a vector in a complex vector space, is denoted by

consisting of a left part,

called the bra /brɑː/, and a right part,


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