Fig. 1: Digital quantum simulation of ground states of the RG model for ten spatial orbitals on a superconducting quantum device.
From: Purification-based quantum error mitigation of pair-correlated electron simulations
a, Energy as a function of the coupling parameter g, estimated using various error-mitigation techniques (markers) and compared to classical models (lines). The classical pCCD results do not converge below a critical value, resulting in their cut-off. b, Log plot of experimental energy error (ignoring the model error from the UpCCD approximation). c, Many-body order parameter for the RG Hamiltonian (see text), again compared to classical models. d, Experimental error in estimating the superconducting order parameter versus the target state in the UpCCD approximation (again ignoring model error). Error bars show 1 standard deviation uncertainty from sampling noise, estimated by propagating variance (raw VQE, PS-VQE) or bootstrapping (EV, PS-VD); see Supplementary Information Section III for details. a.u., arbitrary units.
