Abstract: An array of quantum dot qubits (e.g., an array of spin qubits) relies on a gradient magnetic field to ensure that the qubits are separated in frequency in order to be individually addressable. Furthermore, a strong magnetic field gradient is required to electrically drive the electric dipole spin resonance (EDSR) of the qubits. Quantum dot devices disclosed herein use microcoil arrangements for providing a gradient magnetic field, the microcoil arrangements integrated on the same chip (e.g., on the same die or wafer) as quantum dot qubits themselves. Unlike previous approaches to quantum dot formation and manipulation, various embodiments of the quantum dot devices disclosed herein may enable improved control over magnetic fields and their gradients to realize better frequency targeting of individual qubits, help minimize adverse effects of charge noise on qubit decoherence and provide good scalability in the number of quantum dots included in the device.

Abstract: Disclosed herein are lateral gate material arrangements for quantum dot devices, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a quantum well stack; and a gate above the quantum well stack, wherein the gate includes a gate electrode, the gate electrode includes a first material proximate to side faces of the gate and a second material proximate to a center of the gate, and the first material has a different material composition than the second material.

Abstract: Embodiments of the present disclosure describe quantum circuit assemblies that include one or more filter modules integrated in a package with a quantum circuit component having at least one qubit device. Integration may be such that both the quantum circuit component and the filter module(s) are at least partially inside a chamber formed by a radiation shield structure that is configured to attenuate electromagnetic radiation incident on the quantum circuit component and the filter module(s). Placing filter modules under the protection provided by the radiation shield structure may boost coherence of the qubits. Some example filter modules may include filter(s) configured to convert electromagnetic radiation to heat and filter(s) configured to perform bandpass filtering. Modular blocks of in-line filters inside the shielded environment may allow to route signals to the quantum circuit component with reduced noise and speed up installation of a complete quantum computer.