Abstract: The present disclosure relates to a kinetic inductance parametric amplifier that comprises an input port arranged to receive a pump tone, a DC bias and input signal; an output port arranged to provide an amplified version of the input signal; a tunable stepped-impedance assembly arranged to attenuate and/or filter predetermined frequency bands; and a high kinetic inductance line. The tunable stepped-impedance assembly is tuned at a frequency that allows for the amplifier to resonate at a predetermined frequency and a pump tone with a frequency higher than the input signal and a DC biasing signal to be transmitted to the high kinetic inductance line.

Abstract: Aspects of the present disclosure are directed to quantum processing systems that include a plurality of donor atom qubits positioned in a semiconductor substrate. The system also comprises a plurality of control gates configured to control the donor atom qubits. The system further comprises an SLQD charge sensor fabricated on/in the semiconductor substrate. The SLQD charge sensor is configured to sense spin-states of two or more donor atom qubits, which are positioned within a sensing range of the SLQD charge sensor.

Abstract: A quantum processing element is disclosed. The element includes a semiconductor substrate, a dielectric material forming an interface with the semiconductor substrate, and a donor molecule embedded in the semiconductor. The donor molecule includes a plurality of dopant dots embedded in the semiconductor, each dopant dot includes one or more dopant atoms, and one or more electrons/holes confined to the dopant dots. A distance between the dopant dots is between 3 and 9 nanometres.

Abstract: A method for readout of a singlet-triplet qubit in a donor based quantum processing element is disclosed. The method includes: initialising the singlet-triplet qubit in a ground state |G; performing a shelving readout; using a final measured charge configuration of the singlet-triplet qubit to determine information about a current Zeeman energy difference; and using the information about the current Zeeman energy difference to adjust mapping of the shelving readout.

Abstract: One-dimensional and two-dimensional arrays of qubits are disclosed. The one-dimensional array includes two or more double-quantum dots embedded in silicon, the two or more double-quantum dots arranged in an Echelon formation, such that the distance between the two or more double-quantum dots is approximately 40 nm and the distance between the two quantum dots in each double-quantum dot is approximately 12 nm; two or more reservoirs to load electrons to the corresponding two or more double-quantum dots to form singlet-triplet qubits in each double-quantum dot; and two or more gates for controlling the formed singlet-triplet qubits. The two-dimensional array of qubits includes two or more layers of vertically-stacked one-dimensional arrays of qubits.

Abstract: A method for measuring the spin of an electron in a quantum dot that is tunnel coupled to a reservoir is disclosed. The method includes measuring a spin state of the injected electron while applying a ramped detuning for a time period.