Blind quantum computation with a heralded single-photon source

Blind quantum computation is a scheme that adds unconditional security to cloud quantum computation. In the protocol proposed by Broadbent, Fitzsimons, and Kashefi, the ability to prepare and transmit a single qubit is required for a user (client) who uses a quantum computer remotely. In case a weak coherent pulse is used as a pseudo-single-photon source, however, we must introduce decoy states, owing to the inherent risk of transmitting multiple photons. In this paper, we demonstrate that by using a heralded single-photon source and a probabilistic photon number resolving detector we can gain a higher blind state generation efficiency and longer access distance, owing to noise reduction on account of the heralding signal.

Figure 1

Dependence of $S/N$ on $\mu$ (${\eta }_A=0.85,d_A=1.0\times {10}^{-8}$).

Figure 2

$S/N$ dependence on $\mu$ (${\eta }_A=0.04,d_A=1.0\times {10}^{-12}$).

Figure 3

$S/N$ dependence on distance (${\eta }_A=0.85$, $d_A=1.0\times {10}^{-8}$).

Figure 4

$S/N$ dependence on distance up to 1000 km (${\eta }_A=0.85,d_A=1.0\times {10}^{-8}$).

Figure 5

$S/N$ dependence on distance (${\eta }_A=1.0,d_A=1.0\times {10}^{-8}$).

Figure 6

$S/N$ dependence on distance (purple solid line, WCP; green dashed line, HSPS with ${\eta }_A=1.0,d_A=1.0\times {10}^{-8}$; blue dotted line, HSPS with ${\eta }_A=1.0,d_A=1.0\times {10}^{-12}$).