Fig. 1: Experimental setups.
From: Experimental quantum kernel trick with nuclear spins in a solid
a Adamantane molecule. The white and pink balls represent hydrogen and carbon atoms, respectively. b Quantum circuit and pulse sequence employed in this work to realize evaluation of kNMR(xi, xj). The top right shows a pulse sequence for x1 = 0, where X and \(\bar{{\rm{X}}}\) represent +π/2 and −π/2 pulses along x-axis, respectively. In the experiment, Δ and \({{\Delta }}^{\prime}\) are set 3.5 μs and 8.5 μs, respectively. c NMR kernel employed in this work. d Fourier transform of (c) which corresponds to the obtained 1H multiple-quantum spectra for N = 1 to N = 6. Red line is Gaussian \(a\exp (-{m}^{2}/K)\) fitted to the spectra using a and K as fitting parameters. The Gaussian is fitted only to even m data points. K is the cluster size of the system18,30,33.
