rank one operators #
This defines the rank one operator $| x \rangle\!\langle y |$ for continuous linear maps
(see rank_one
) and linear maps (see rank_one_lm
).
we define the rank one operator $| x \rangle\!\langle y |$ by $x \mapsto \langle y, z \rangle \cdot x$
$| x \rangle\!\langle \alpha\cdot y | = \bar{\alpha} \cdot | x \rangle\!\langle y |$
$| \alpha \cdot x \rangle\!\langle y | = \alpha \cdot | x \rangle\!\langle y |$
$| x \rangle\!\langle y | | z \rangle\!\langle w | = \langle y, z \rangle \cdot | x \rangle\!\langle w |$
$u \circ | x \rangle\!\langle y | = | u(x) \rangle\!\langle y |$
$| x \rangle\!\langle y | \circ u = | x \rangle\!\langle u^*(y) |$
rank one operators given by norm one vectors are automatically idempotent
rank one operators are automatically self-adjoint
$| x \rangle\!\langle y |^* = | y \rangle\!\langle x |$
same as rank_one
, but as a linear map
Equations
- rank_one_lm x y = (rank_one x y).to_linear_map