Disclosed herein are quantum dot devices with trenched substrates, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a substrate having a trench disposed therein, wherein a bottom of the trench is provided by a first material, and a quantum well stack at least partially disposed in the trench. A material of the quantum well stack may be in contact with the bottom of the trench, and the material of the quantum well stack may be different from the first material.

Quantum dot devices, and related systems and methods, are disclosed herein. In some embodiments, a quantum dot device may include a quantum well stack; a plurality of first gate lines above the quantum well stack; a plurality of second gate lines above the quantum well stack, wherein the second gate lines are perpendicular to the first gate lines; and an array of regularly spaced magnet lines.

Quantum dot devices, and related systems and methods, are disclosed herein. In some embodiments, a quantum dot device may include a quantum well stack having a first face and a second opposing face; an array of parallel first gate lines at the first face or the second face of the quantum well stack; and an array of parallel second gate lines at the first face or the second face of the quantum well stack, wherein the second gate lines are oriented diagonal to the first gate lines.

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 including a quantum well layer, wherein the quantum well layer includes an isotopically purified material; a gate dielectric above the quantum well stack; and a gate metal above the gate dielectric, wherein the gate dielectric is between the quantum well layer and the gate metal.

A quantum bit array is disclosed. In an embodiment, the quantum bit array includes a control gate coupled to a qubit and at least one pass gate coupled between the qubit and an adjacent qubit to control operation of the qubit of the quantum bit array, a bit line, and a first transistor channel that connects the bit line to the control gate. The array further comprises at least one word line coupled to the first transistor channel. The at least one word line selectively controls charge flow through the first transistor channel. The array further comprises a capacitor coupled to selectively store charge in the first transistor channel.

A fabrication method for a semiconductor structure with a hole spin qubit includes: providing a substrate; growing a germanium quantum well on the substrate, in which the germanium quantum well is an inclined quantum well structure grown in a [110] direction, and the germanium quantum well is grown by a complementary metal oxide semiconductor process; and fabricating a two-dimensional gate-defined quantum dot in the germanium quantum well.

Methods, devices, and systems are described for storing and transferring quantum information. An example device may comprise at least one semiconducting layer, one or more conducting layers configured to define at least two quantum states in the at least one semiconducting layer and confine an electron in or more of the at least two quantum states, and a magnetic field source configured to generate an inhomogeneous magnetic field. The inhomogeneous magnetic field may cause a first coupling of an electric charge state of the electron and a spin state of the electron. The device may comprise a resonator configured to confine a photon. An electric-dipole interaction may cause a second coupling of an electric charge state of the electron to an electric field of the photon.

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 including a quantum well layer and a barrier layer; a first gate metal above the quantum well stack, wherein the barrier layer is between the first gate metal and the quantum well layer; and a second gate metal above the quantum well stack, wherein the barrier layer is between the second gate metal and the quantum well layer, and a material structure of the second gate metal is different from a material structure of the first gate metal.

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 (111) silicon substrate, a (111) germanium quantum well layer above the substrate, and a plurality of gates above the quantum well layer. In some embodiments, a quantum dot device may include a silicon substrate, an insulating material above the silicon substrate, a quantum well layer above the insulating material, and a plurality of gates above the quantum well layer.

The present disclosure relates to an electronic combiner circuit comprising: a DC bias input, an AC control input and a signal output; the DC bias input being arranged to receive a DC signal and couple the DC signal to the signal output in DC; the AC control input being arranged to receive an AC signal and couple the AC signal to the signal output at any frequency; the signal output being arranged to provide a combined signal for operating a quantum device; a first conductive path arranged between the AC input and the signal output; the first conductive path being such that the DC component of a signal provided at the AC input is prevented from being transmitted from the AC input to the signal output along the first conductive path; a second conductive path arranged between the AC input and the signal output; the second conductive path being such that the DC component of a signal provided at the AC input transmits from the AC input to the signal output along the second conductive path.