Abstract: Technologies for two-dimensional spin qubit arrays are disclosed. In an illustrative embodiment, a quantum processor die includes a two-dimensional array of spin qubits. Single-electron transistors (SETs) are arranged near an upper and lower boundary around the two-dimensional array of spin qubits. Each SET may be positioned to be able to read, e.g., qubits from two rows, allowing for the state of four rows of qubits to be read by the SETs above and below the array of qubits. The two-dimensional array of spin qubits may allow for a large number of physical and logical qubits in communication with each other, allowing for large scale quantum computation.

Abstract: Technologies for radiofrequency optimized interconnects for a quantum processor are disclosed. In the illustrative embodiment, signals are carried in coplanar waveguides on a surface of a quantum processor die. A ground ring surrounds the signals and is connected to the ground conductors of each coplanar waveguide. Wire bonds connect the ground ring to a ground of a circuit board. The wire bonds provide both an electrical connection from the quantum processor die to the circuit board as well as increased thermal coupling between the quantum processor die and the circuit board, increasing cooling of the quantum processor die.

Abstract: 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 EDSR of the qubits. Quantum dot devices and related methods and systems that integrate magnetic materials in the gates to provide a gradient magnetic field are disclosed. Magnetic materials in different gates may be of different heights to improve frequency separation of neighboring qubits. 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: 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: 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: 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.