Fig. 5
We prepare the state \(|\Psi ^-\rangle\) off-chip and couple it into the photonic chip, with the chip functioning as two full quantum state tomography (FST) units. We perform FST on the state and analyse the results by maximum likelihood estimation. Here, the (a) real and (b) imaginary parts of the recovered density matrix are visualised. The fidelity of the measured state is 97.3(2)% and its purity is 97.6(5)%. As a benchmark for the on-chip FST units, we also perform off-chip FST on the prepared Bell state. The recovered density matrix’ (c) real and (d) imaginary parts are visualised. We determine a fidelity of 99.109(6)% and a purity of 99.321(15)%.
