Figure 1 | Scientific Reports

Figure 1

From: Experimental realization of equiangular three-state quantum key distribution

Figure 1

States used in the R04 protocol (above) and POVM {Πi} used for the measurement (below).

The states lie in the X-Z plane of the Bloch sphere. They are grouped into the sets S1 = {|ψ1〉, |ψ2〉}, S2 = {|ψ2〉, |ψ3〉} and S3 = {|ψ3〉, |ψ1〉}, where the first element of each set corresponds to bit 0 and the second to bit 1. The POVM is implemented by using a partially polarizing beam-splitter (pPBS), a half-wave plate (HWP) at 22.5° and a polarizing beam-splitter (PBS).

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