Table 1 Comparison of distribution protocols for a fully non-locally N-controlled unitary.
Ancillary Qubits | Maximum Qubits Locally | EPR pairs consumed | Time | |
|---|---|---|---|---|
2N | \(N+M\) | N | \({\mathcal {O}}\left( 1\right)\) | |
Sequential Cascade (Fig. 4) | 2N | \(\max \left\{ 3,\,M+1\right\}\) | N | \({\mathcal {O}}\left( N\right)\) |
Binary Parallel Cascades (Fig. 3) | 2N | \(\max \left\{ 4,\,M+2\right\}\) | N | \({\mathcal {O}}\left( \log N\right)\) |
\(\sqrt{N}\) Parallel Cascades (Fig. 3) | 2N | \(\lceil \sqrt{N}+M\rceil\) | N | \({\mathcal {O}}\left( 1\right)\) |