David Landhuis

TL;DR: In this paper, an updated version of supplementary information to accompany "Quantum supremacy using a programmable superconducting processor", an article published in the October 24, 2019 issue of Nature, is presented.

TL;DR: Quantum supremacy is demonstrated using a programmable superconducting processor known as Sycamore, taking approximately 200 seconds to sample one instance of a quantum circuit a million times, which would take a state-of-the-art supercomputer around ten thousand years to compute.

TL;DR: Several quantum simulations of chemistry with up to one dozen qubits are performed, including modeling the isomerization mechanism of diazene, and error-mitigation strategies based on N-representability that dramatically improve the effective fidelity of the experiments are demonstrated.

TL;DR: The application of the Google Sycamore superconducting qubit quantum processor to combinatorial optimization problems with the quantum approximate optimization algorithm (QAOA) is demonstrated and an approximation ratio is obtained that is independent of problem size and for the first time, that performance increases with circuit depth.

TL;DR: This work implements two gate families: an imaginary swap-like (iSWAP-like) gate to attain an arbitrary swap angle, θ, and a controlled-phase gate that generates an arbitrary conditional phase, ϕ that can provide a threefold reduction in circuit depth as compared to a standard decomposition.