Abstract: Systems and methods for magnetic shielding are described. A magnetic shield formed of a material having a high magnetic permeability may be degaussed using a toroidal degaussing coil. The toroidal degaussing coil may enclose at least a portion of the shield. Magnetic field gradients may be actively compensated using multiple magnetic field sensors and local compensation coils. Trapped fluxons may be removed by an application of Lorentz force wherein an electrical current is passed through a superconducting plane.

Abstract: Adaptations and improvements to tubular metal powder filters include employing non-circular cross sectional geometries, aligning the inner conductor off-axis, replacing the inner conductive wire with a conductive trace carried on a printed circuit board, combining multiple filters within a single common outer conductive housing, and employing meandering and other non-parallel signal paths. The various adaptations and improvements are designed to accommodate single-ended and differential signaling, as well as superconducting and non-superconducting applications.

Abstract: Solving computational problems may include generating a logic circuit representation of the computational problem, encoding the logic circuit representation as a discrete optimization problem, and solving the discrete optimization problem using a quantum processor. Output(s) of the logic circuit representation may be clamped such that the solving involves effectively executing the logic circuit representation in reverse to determine input(s) that corresponds to the clamped output(s). The representation may be of a multiplication circuit. The discrete optimization problem may be composed of a set of miniature optimization problems, where each miniature optimization problem encodes a respective logic gate from the logic circuit representation. A multiplication circuit may employ binary representations of factors, and these binary representations may be decomposed to reduce the total number of variables required to represent the multiplication circuit.

Abstract: Systems and methods for operating digital computer system and a quantum processor to optimize an investment portfolio are described. A set of candidate investments is mapped to the qubits of the quantum processor, where each qubit is programmed with a respective programmable qubit parameter that is representative of the recent performance of the particular candidate investment to which the qubit corresponds. Pair-wise correlations between the candidate investments are mapped to coupling devices of the quantum processor, where each coupling device is programmed with a respective programmable coupling parameter that is representative of the particular correlation to which the coupling device corresponds. The quantum processor is evolved to determine the minimum energy configuration of the qubit states with respect to the programmable qubit and coupling device parameters. The digital computer system interacts with the quantum processor via an investment portfolio optimization module.