Abstract: Quantum dot devices with independent gate control are disclosed. An example quantum dot device includes N parallel rows of gate lines provided over a quantum well stack. Each of the N parallel rows of gate lines defines a respective row of a quantum dot formation region in the quantum well stack and includes M parallel gate lines stacked above one another. The quantum dot device may further include, for each of the N×M gate lines, a gate that extends toward the quantum well stack, where, for an individual row of the N parallel rows, gates that extend toward the quantum well stack from the M parallel stacked gate lines are arranged above a respective row of a quantum dot formation region in the quantum well stack. In this manner, each of the N×M gates responsible for formation of different quantum dots may be controlled independently.

Abstract: Disclosed herein are 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; a first gate above the quantum well stack, wherein the first gate includes a first gate metal and a first gate dielectric; and a second gate above the quantum well stack, wherein the second gate includes a second gate metal and a second gate dielectric, and the first gate is at least partially between a portion of the second gate and the quantum well stack.

Abstract: Quantum dot devices with three of more accumulation gates provided over a single row of a quantum dot formation region are disclosed. Each accumulation gate is electrically coupled to a respective doped region. In this manner, multiple single electron transistors (SETs) are provided along the row. Side and/or center screening gates may be used to apply microwave pulses for qubit control and to control electrostatics so that source and drain regions of the multiple SETs with quantum dots formed along the single row of a quantum dot formation region are sufficiently isolated from one another. Such quantum dot devices provide strong spatial localization of the quantum dots, good control over quantum dot interactions and manipulation, good scalability in the number of quantum dots included in the device, and/or design flexibility in making electrical connections to the quantum dot devices to integrate the quantum dot devices in larger computing devices.

Abstract: A method and apparatus for calcining calcium sulphate dihydrate in a calcination vessel in which the dihydrate is heated in the vessel to calcination temperature not only by heat applied to the exterior of the vessel but also by hot gas, especially hot gaseous combustion products, supplied into the interior of the mass of calcining material within the vessel. The supply of hot gas according to the invention can improve the production rate in both batch and continuous calcination operations without adversely affecting the product quality, by permitting increase in the heat input to the vessel without entailing the risk of vessel bottom burn-out.