Techniques regarding lithographic processes for fabricating Josephson junctions are provided. For example, one or more embodiments described herein can comprise a method that can include depositing a first resist layer onto a second resist layer. The first resist layer can include a bridge portion that defines an opening for forming a Josephson junction. The method can also comprise depositing a third resist layer onto the bridge portion. The third resist layer can shield the opening from an angled deposition of a superconducting material during fabrication of the Josephson junction.

In a method for forming joints between MgB.sub.2 filaments of superconducting wires, the MgB.sub.2 filaments from the wires to be joined are exposed, and the exposed filaments are then exposed to a mixture of magnesium powder and boron powder in a furnace, and the MgB.sub.2 filaments and the magnesium and boron powders are pressed together in the furnace. The MgB.sub.2 filaments and the magnesium and the boron powders in the furnace are heated, and oxygen that is present within the furnace is preferentially trapped, and thus removed from the joint, by providing titanium within the furnace.

Superconducting integrated circuits and methods of forming these circuits are discussed. One superconducting integrated circuit has a substrate and a control device formed by a layer of high kinetic inductance material overlying the substrate. The control device has a loop of material, electrical connections between the loop of material and a power line, a coupling element connected to the loop of material, a pair of Josephson junctions that interrupt the loop of material, and an energy storage element connected to the loop of material. An alternative superconducting integrated circuit has a kinetic inductance device formed in a high kinetic inductance layer. The device has a compound Josephson junction structure with two parallel current paths with respective Josephson junctions, a loop of material connected to the compound Josephson junction structure, and a coupling structure. The circuit also has an additional device that couples to the coupling structure.

Systems and techniques that facilitate space-saving coupler arm arrangement for superconducting qubits are provided. In various embodiments, a device can comprise a superconducting qubit. In various aspects, the superconducting qubit can be capacitively coupled to two or more coupler arms. In various instances, a parasitic capacitance between the two or more coupler arms can be within an order of magnitude of a capacitance between the superconducting qubit and at least one of the two or more coupler arms. In various cases, the parasitic capacitance can arise due to a physical proximity between the two or more coupler arms.

A method for producing a hybrid structure, the hybrid structure including at least one structured Majorana material and at least one structured superconductive material arranged thereon includes producing, on a substrate, a first mask for structured application of the Majorana material and a further mask for structured growth of the at least one superconductive material, which are aligned relatively to one another, and applying the at least one structured superconductive material to the structured Majorana material with the aid of the further mask. The structured application of the Majorana material and of the at least one superconductive material takes place without interruption in an inert atmosphere.

Magneto-optical modulator-based systems and devices for transferring quantum information are described. Such systems can be used for many applications, including as part of quantum computers. An example system includes a quantum information system configured to provide a signal corresponding to at least one qubit. The system further includes a magneto-optical driver configured to receive the signal corresponding to the at least one qubit and process the signal to generate a current based on the signal corresponding to the at least one qubit. The system further includes a magneto-optical modulator configured to receive the current from the magneto-optical driver and provide a modulated light output by modulating a received light input based on the current.

A solid state cooler device is disclosed that comprises a first normal metal pad, a first aluminum layer and a second aluminum layer disposed on the first normal metal pad and separated from one another by a gap, a first aluminum oxide layer formed on the first aluminum layer, and a second aluminum oxide layer formed on the second aluminum layer, and a first superconductor pad disposed on the first aluminum oxide layer and a second superconductor pad disposed on the second aluminum oxide layer. The device further comprises a first conductive pad coupled to the first superconductor pad, and a second conductive pad coupled to the second superconductor pad, wherein hot electrons are removed from the first normal metal pad when a bias voltage is applied between the first conductive pad and the second conductive pad.

Systems and techniques that facilitate mode-selective couplers for frequency collision reduction are provided. In various embodiments, a device can comprise a control qubit. In various aspects, the device can comprise a first target qubit coupled to the control qubit by a first mode-selective coupler. In various instances, the first mode-selective coupler can facilitate A-mode coupling between the control qubit and the first target qubit. In various embodiments, the device can comprise a second target qubit coupled to the control qubit by a second mode-selective coupler. In various aspects, the second mode selective coupler can facilitate B-mode coupling between the control qubit and the second target qubit. In various embodiments, the first mode-selective coupler can comprise a capacitor that capacitively couples a middle capacitor pad of the control qubit to a middle capacitor pad of the first target qubit. In various embodiments, the second mode-selective coupler can comprise a first capacitor that capacitively couples an end capacitor pad of the control qubit to an end capacitor pad of the first target qubit and can comprise a second capacitor that capacitively couples the end capacitor pad of the control qubit to a middle capacitor pad of the second target qubit.

Devices and/or computer-implemented methods facilitating static ZZ suppression and Purcell loss reduction using mode-selective coupling in two junction superconducting qubits are provided. In an embodiment, a device can comprise a superconducting bus resonator. The device can further comprise a first superconducting qubit. The device can further comprise a second superconducting qubit, the first superconducting qubit and the second superconducting qubit respectively comprising: a first superconducting pad; a second superconducting pad; a third superconducting pad; a first Josephson Junction coupled to the first superconducting pad and the second superconducting pad; and a second Josephson Junction coupled to the second superconducting pad and the third superconducting pad. The first superconducting pad and the second superconducting pad of the first superconducting qubit and the second superconducting qubit are coupled to the superconducting bus resonator. The superconducting bus resonator entangles the first superconducting qubit and the second superconducting qubit based on receiving a control signal.

A quantum chip is provided, includes: a first substrate and a second substrate arranged opposite to each other, wherein a plurality of qubits and a plurality of first controllers are arranged on a surface of the first substrate facing the second substrate, each of the plurality of qubits is coupled with at least one of the plurality of first controllers, and a plurality of control signal transmission parts are arranged on a surface of the second substrate facing the first substrate; and a plurality of connecting pieces, connected between the first substrate and the second substrate, and configured to connect the plurality of first controllers to the plurality of control signal transmission parts in a one-to-one corresponding mode.