Table 2 Characteristic of a two-cascaded CZ gate on metasurface
(a) Encoding rules of signal polarization qubit | ||||
|---|---|---|---|---|
| Â | Signal | Auxiliary | ||
Polarization state | \({| R\left.\right\rangle }_{-1}\) | \({| L\left.\right\rangle }_{-1}\) | \({| R\left.\right\rangle }_{+2}\) | \({| L\left.\right\rangle }_{-2}\) |
Encoded qubit state | \({| 0\left.\right\rangle }_{S}\) | \({| 1\left.\right\rangle }_{S}\) | None | None |
Mode label | \({\hat{S}}_{0}^{R}\) | \({\hat{S}}_{1}^{L}\) | \({\hat{V}}^{R}\) | \({\hat{V}}^{L}\) |
(b) Truth table of 3-qubit input states | ||||
|---|---|---|---|---|
S&T in standard basis | S&T in Hadamard basis | Â | ||
Input | Output | Input | Output | Post-selection probability |
\({| 0\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | 1/27 |
\({| 0\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | 1/27 |
\({| 0\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \(-{| 0\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | 1/27 |
\({| 0\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \(-{| 0\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | \({| 0\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | 1/27 |
\({| 1\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | 1/27 |
\({| 1\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \(-{| 1\left.\right\rangle }_{C}{| 0\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| +\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | 1/27 |
\({| 1\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 0\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | 1/27 |
\({| 1\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \(-{| 1\left.\right\rangle }_{C}{| 1\left.\right\rangle }_{S}{| 1\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| -\left.\right\rangle }_{T}\) | \({| 1\left.\right\rangle }_{C}{| -\left.\right\rangle }_{S}{| +\left.\right\rangle }_{T}\) | 1/27 |