Circuit fragments. For example, the
circuit in Figure 3 is from Childs et al.4
Note, strictly speaking, the figure describes
a family of quantum circuits,
parameterized by a rotation angle t and
a size parameter n, as indicated by ellipses
“. . .” in the informal circuit. In
a formal implementation, this parameter
dependency must be made explicit;
High-level operations on circuits.
Examples include “inversion,” where
a circuit is reversed, and “iteration,”
where a circuit is repeated, as in Figure
4; and