qit.gate.plusdot

qit.gate.plusdot(n_in, n_out, d=2)

Plus dot.

The dual of copydot. Connecting computational basis states to all of its legs causes it to vanish unless the sum of the basis state labels is zero (mod d).

$$\begin{array}{r}{\mathrm{PLUS}}^{n_{\text{in}}\to n_{\text{out}}}=\frac{1}{d^{(m+n-2)/2}}\sum _{\begin{array}{c}{r}_1\cdots r_{n_{\text{in}}}\\ s_1\cdots s_{n_{\text{out}}}\end{array}}{\delta }_{(\sum _i{r}_i\oplus \sum _j{s}_j),0}|s_1\cdots s_{n_{\text{out}}}⟩⟨r_1\cdots r_{n_{\text{in}}}|,\end{array}$$

Parameters

• n_in (int) – number of input legs

• n_out (int) – number of ouput legs

• d (int) – leg dimension

Returns

plus dot

Return type

Lmap

See [9]