a vector a ket and denote it by |a>
This state ket is postulated to contain complete information about the physical state;
everything we are allowed to ask about the state is contained in the ket.
Hell Fast@hellfast.bsky.social
An observable, such as momentum and spin components, can be represented by an operator, such as A
Hell Fast·
the bra ⟨ϕ∣ tells you “how much of the direction ∣ϕ⟩” is contained in ∣ψ⟩
也就是 row vector 是用来计算两个 vectors 之间的关系