Composite Bras and Kets
Two Hilbert spaces V and W may form a third space by a tensor product. In quantum mechanics, this is used for describing composite systems. If a system is composed of two subsystems described in V and W respectively, then the Hilbert space of the entire system is the tensor product of the two spaces. (The exception to this is if the subsystems are actually identical particles. In that case, the situation is a little more complicated.)
If is a ket in V and is a ket in W, the direct product of the two kets is a ket in . This is written variously as
- or or or
Read more about this topic: Bra-ket Notation
Famous quotes containing the words composite and/or bras:
“A positive learning climate in a school for young children is a composite of many things. It is an attitude that respects children. It is a place where children receive guidance and encouragement from the responsible adults around them. It is an environment where children can experiment and try out new ideas without fear of failure. It is an atmosphere that builds children’s self-confidence so they dare to take risks. It is an environment that nurtures a love of learning.”
—Carol B. Hillman (20th century)
“You mean those nuts that burn their bras and walk around all disheveled and hate men? They’re crazy. Crazy.”
—Golda Meir (1898–1978)