Fig. 3: Two-qubit gate fidelities as functions of the ratio between the polariton-polariton interaction strength and the dissipation rate (α/γ).

a Fidelities of square-root-SWAP (blue circles) and SWAP (red diamonds) gates as functions of polariton lifetime. The inset shows a scheme for sSWAP and SWAP operations based on three coupled micropillars. For sSWAP gate, we considered \({E}_{x}^{j}/{E}_{z}^{j}=11.55\), \({E}_{y}^{j}/{E}_{z}^{j}=0\), \({E}_{z}^{j}/\alpha =1\), E_T/α = 45.64 and pulse duration τ = 0.576\({\hbar}\)/α and for SWAP gate, we considered \({E}_{x}^{j}/{E}_{z}^{j}=7.6\), \({E}_{y}^{j}/{E}_{z}^{j}=0\), \({E}_{z}^{j}/\alpha =1\), E_T/α = 48.7 and pulse duration τ = 1.08\({\hbar}\)/α. b Fidelity of a maximally entangled state obtained with a cNOT gate as a function of the polariton lifetime. We considered the parameters \({E}_{x}^{1}={E}_{z}^{1}=0\), \({E}_{x}^{2}/{E}_{z}^{2}=0.05\), \({E}_{z}^{2}/\alpha =1\), \({E}_{z}^{12}/\alpha ={\alpha }_{12}/\alpha =1\) and pulse duration τ = 1.36\({\hbar}\)/α (here α_j = α is the nonlinearity strength). The inset shows a scheme for cNOT operation based on two spin components of a polariton condensate.