Abstract: A method is disclosed, including positioning a lead wire of a gate chip at a distance of less than 10 nm from a semiconductor heterostructure. The heterostructure includes a surface layer and a subsurface layer. The method also includes inducing an electrostatic potential in the subsurface layer by applying a voltage to the lead wire. The method also includes loading a charge carrier into the subsurface layer. The method also includes detecting the charge carrier in the subsurface layer of the semiconductor heterostructure by emitting a radio-frequency pulse using a resonator coupled to the at least one lead wire of the gate chip, detecting a reflected pulse of the emitted radio-frequency pulse, and determining a phase shift of the reflected pulse relative to the emitted radio-frequency pulse. The method also includes characterizing the quantum dot by measuring valley splitting of the quantum dot.

Abstract: A method is disclosed, including positioning a lead wire of a gate chip at a distance of less than 10 nm from a semiconductor heterostructure. The heterostructure includes a surface layer and a subsurface layer. The method also includes inducing an electrostatic potential in the subsurface layer by applying a voltage to the lead wire. The method also includes loading a charge carrier into the subsurface layer. The method also includes detecting the charge carrier in the subsurface layer of the semiconductor heterostructure by emitting a radio-frequency pulse using a resonator coupled to the at least one lead wire of the gate chip, detecting a reflected pulse of the emitted radio-frequency pulse, and determining a phase shift of the reflected pulse relative to the emitted radio-frequency pulse. The method also includes characterizing the quantum dot by measuring valley splitting of the quantum dot.

Abstract: An always-on, exchange-only (AEON) qubit is comprised of three two-level systems (e.g., semiconductor quantum dot or other spin encoded qubit) and can be operated at a “sweet spot” during both single qubit and two-qubit gate operations. The “sweet spot” operation is immune to variations in noise with respect to nontrivial detuning parameters defining the AEON. By operating at the “sweet spot,” both single and two-qubit gate operations can be performed using only exchange pulses (e.g., DC voltage pulses applied to tunneling gates).

Abstract: An always-on, exchange-only (AEON) qubit is comprised of three two-level systems (e.g., semiconductor quantum dot or other spin encoded qubit) and can be operated at a “sweet spot” during both single qubit and two-qubit gate operations. The “sweet spot” operation is immune to variations in noise with respect to nontrivial detuning parameters defining the AEON. By operating at the “sweet spot,” both single and two-qubit gate operations can be performed using only exchange pulses (e.g., DC voltage pulses applied to tunneling gates).

Abstract: Superconducting regions formed with a crystal provide highly doped regions of acceptor atoms. These superconducting regions are used to provide superconducting devices wherein non-epitaxial interfaces have been eliminated. A method is provided to highly doped regions of a crystal to form the superconducting regions and devices. By forming the superconducting regions within the crystal non-epitaxial interfaces are eliminated.

Abstract: Superconducting regions formed with a crystal provide highly doped regions of acceptor atoms. These superconducting regions are used to provide superconducting devices wherein non-epitaxial interfaces have been eliminated. A method is provided to highly doped regions of a crystal to form the superconducting regions and devices. By forming the superconducting regions within the crystal non-epitaxial interfaces are eliminated.

Abstract: Physical superconducting qubits are controlled according to an “encoded” qubit scheme, where a pair of physical superconducting qubits constitute an encoded qubit that can be controlled without the use of a microwave signal. For example, a quantum computing system has at least one encoded qubit and a controller. Each encoded qubit has a pair of physical superconducting qubits capable of being selectively coupled together. Each physical qubit has a respective tunable frequency. The controller controls a state of each of the pair of physical qubits to perform a quantum computation without using microwave control signals. Rather, the controller uses DC-based voltage or flux pulses.

Abstract: Physical superconducting qubits are controlled according to an “encoded” qubit scheme, where a pair of physical superconducting qubits constitute an encoded qubit that can be controlled without the use of a microwave signal. For example, a quantum computing system has at least one encoded qubit and a controller. Each encoded qubit has a pair of physical superconducting qubits capable of being selectively coupled together. Each physical qubit has a respective tunable frequency. The controller controls a state of each of the pair of physical qubits to perform a quantum computation without using microwave control signals. Rather, the controller uses DC-based voltage or flux pulses.

Abstract: An artificial composite object combines a quantum of sound with a matter excitation. A phonon in a confinement structure containing the matter excites it from an initial state to an excited state corresponding to a frequency of the phonon. Relaxation of the matter back to the initial state emits a phonon of the same frequency into the confinement structure. The phonon confinement structure, for example, a cavity, traps the emitted phonon thereby allowing further excitation of the matter. The coupling between the phonon and the matter results in a quantum quasi-particle referred to as a phoniton. The phoniton can find application in a wide variety of quantum systems such as signal processing and communications devices, imaging and sensing, and information processing.

Abstract: An artificial composite object combines a quantum of sound with a matter excitation. A phonon in a confinement structure containing the matter excites it from an initial state to an excited state corresponding to a frequency of the phonon. Relaxation of the matter back to the initial state emits a phonon of the same frequency into the confinement structure. The phonon confinement structure, for example, a cavity, traps the emitted phonon thereby allowing further excitation of the matter. The coupling between the phonon and the matter results in a quantum quasi-particle referred to as a phoniton. The phoniton can find application in a wide variety of quantum systems such as signal processing and communications devices, imaging and sensing, and information processing.

Abstract: An artificial composite object combines a quantum of sound with a matter excitation. A phonon in a confinement structure containing the matter excites it from an initial state to an excited state corresponding to a frequency of the phonon. Relaxation of the matter back to the initial state emits a phonon of the same frequency into the confinement structure. The phonon confinement structure, for example, a cavity, traps the emitted phonon thereby allowing further excitation of the matter. The coupling between the phonon and the matter results in a quantum quasi-particle referred to as a phoniton. The phoniton can find application in a wide variety of quantum systems such as signal processing and communications devices, imaging and sensing, and information processing.

Abstract: An artificial composite object combines a quantum of sound with a matter excitation. A phonon in a confinement structure containing the matter excites it from an initial state to an excited state corresponding to a frequency of the phonon. Relaxation of the matter back to the initial state emits a phonon of the same frequency into the confinement structure. The phonon confinement structure, for example, a cavity, traps the emitted phonon thereby allowing further excitation of the matter. The coupling between the phonon and the matter results in a quantum quasi-particle referred to as a phoniton. The phoniton can find application in a wide variety of quantum systems such as signal processing and communications devices, imaging and sensing, and information processing.

Abstract: A semiconductor quantum dot device converts spin information to charge information utilizing an elongated quantum dot having an asymmetric confining potential along its length so that charge movement occurs during orbital excitation. A single electron sensitive electrometer is utilized to detect the charge movement. Initialization and readout can be carried out rapidly utilizing RF fields at appropriate frequencies.