Abstract: Methods, systems, and apparatus for nonlinear calibration of quantum computing apparatus. In one aspect, elements in a set of experimental data correspond to a respective configuration of control biases for the quantum computing apparatus. An initial physical model comprising one or more model parameters of the quantum computing apparatus is defined. The model is iteratively adjusted to determine a revised physical model, where at each iteration: a set of predictive data corresponding to the set of experimental data is generated, and elements in the predictive data represent a difference between the two smallest eigenvalues of a Hamiltonian characterizing the system qubits for the previous iteration, and are dependent on at least one model parameter of the physical model for the previous iteration; and the model for the previous iteration is adjusted using the obtained experimental data and the generated set of predictive data for the iteration.

Abstract: Methods, systems, and apparatus for nonlinear calibration of quantum computing apparatus. In one aspect, elements in a set of experimental data correspond to a respective configuration of control biases for the quantum computing apparatus. An initial physical model comprising one or more model parameters of the quantum computing apparatus is defined. The model is iteratively adjusted to determine a revised physical model, where at each iteration: a set of predictive data corresponding to the set of experimental data is generated, and elements in the predictive data represent a difference between the two smallest eigenvalues of a Hamiltonian characterizing the system qubits for the previous iteration, and are dependent on at least one model parameter of the physical model for the previous iteration; and the model for the previous iteration is adjusted using the obtained experimental data and the generated set of predictive data for the iteration.

Abstract: A device includes: a first qubit including a first co-planar waveguide; a second qubit including a second co-planar waveguide, in which the second co-planar waveguide crosses the first co-planar waveguide; and a qubit coupler including a loop having a first lobe and a second lobe, in which a first portion of the first lobe extends parallel to the first co-planar waveguide, a second portion of the first lobe extends parallel to the second co-planar waveguide, a first portion of the second lobe extends parallel to the first co-planar waveguide, and a second portion of the second lobe extends parallel to the second co-planar waveguide.

Abstract: A device includes: a first qubit including a first co-planar waveguide; a second qubit including a second co-planar waveguide, in which the second co-planar waveguide crosses the first co-planar waveguide; and a qubit coupler including a loop having a first lobe and a second lobe, in which a first portion of the first lobe extends parallel to the first co-planar waveguide, a second portion of the first lobe extends parallel to the second co-planar waveguide, a first portion of the second lobe extends parallel to the first co-planar waveguide, and a second portion of the second lobe extends parallel to the second co-planar waveguide.

Abstract: A device includes: a first qubit including a first co-planar waveguide; a second qubit including a second co-planar waveguide, in which the second co-planar waveguide crosses the first co-planar waveguide; and a qubit coupler including a loop having a first lobe and a second lobe, in which a first portion of the first lobe extends parallel to the first co-planar waveguide, a second portion of the first lobe extends parallel to the second co-planar waveguide, a first portion of the second lobe extends parallel to the first co-planar waveguide, and a second portion of the second lobe extends parallel to the second co-planar waveguide.

Abstract: A device includes: a first qubit including a first co-planar waveguide; a second qubit including a second co-planar waveguide, in which the second co-planar waveguide crosses the first co-planar waveguide; and a qubit coupler including a loop having a first lobe and a second lobe, in which a first portion of the first lobe extends parallel to the first co-planar waveguide, a second portion of the first lobe extends parallel to the second co-planar waveguide, a first portion of the second lobe extends parallel to the first co-planar waveguide, and a second portion of the second lobe extends parallel to the second co-planar waveguide.