Aspects of the present disclosure relate generally to systems and methods for use in the implementation and/or operation of quantum information processing (QIP) systems, and more particularly, to techniques for removing or correcting for translation errors between a programmed strength and an applied strength of quantum gates. A method is described that includes determining, for each quantum gate in a quantum operation, a non-linearity between an applied strength of a laser beam used for the respective quantum gate and a programmed strength intended to be applied by the laser beam for the respective quantum gate. The method further includes linearizing the non-linearity for each quantum gate and storing linearization information in memory. Moreover, the method includes applying the linearization information to correct for the non-linearity when implementing each quantum gate as part of the quantum operation. A system is also described that is configured to implement the method described above.

Aspects of the present disclosure relate generally to systems and methods for use in the implementation and/or operation of quantum information processing (QIP) systems, and more particularly, to techniques for removing or correcting for translation errors between a programmed strength and an applied strength of quantum gates. A method is described that includes determining, for each quantum gate in a quantum operation, a non-linearity between an applied strength of a laser beam used for the respective quantum gate and a programmed strength intended to be applied by the laser beam for the respective quantum gate. The method further includes linearizing the non-linearity for each quantum gate and storing linearization information in memory. Moreover, the method includes applying the linearization information to correct for the non-linearity when implementing each quantum gate as part of the quantum operation. A system is also described that is configured to implement the method described above.

In an aspect, the present disclosure provides a superconducting circuit including: a ground plane including a superconducting member; a plurality of superconducting parts surrounded by a non-conductive part with space from the ground plane, each of the plurality of superconducting parts including four coupling ports each configured to enable the superconducting part to interact with another superconducting part; a superconducting quantum interference device configured to set a resonance frequency of a first superconducting part included in the plurality of superconducting parts; and a multilevel wiring line configured to form, in cooperation with the ground plane, a superconducting loop surrounding the superconducting quantum interference device, in which the superconducting quantum interference device is disposed, in an area inside the superconducting loop, at a place where a magnetic field generated by a current from a bias line for the first superconducting part is applied.

In an aspect, the present disclosure provides a superconducting circuit including: a ground plane including a superconducting member; a plurality of superconducting parts surrounded by a non-conductive part with space from the ground plane, each of the plurality of superconducting parts including four coupling ports each configured to enable the superconducting part to interact with another superconducting part; a superconducting quantum interference device configured to set a resonance frequency of a first superconducting part included in the plurality of superconducting parts; and a multilevel wiring line configured to form, in cooperation with the ground plane, a superconducting loop surrounding the superconducting quantum interference device, in which the superconducting quantum interference device is disposed, in an area inside the superconducting loop, at a place where a magnetic field generated by a current from a bias line for the first superconducting part is applied.

An electronic component (10) is formed by a semiconductor component or a semiconductor-like structure having gate electrode assemblies (16, 18), for reading out the quantum state of a qubit in a quantum dot (42). The electronic component (10) comprises a substrate (12) having a two-dimensional electron gas or electron hole gas. Electrical contacts connect the gate electrode assemblies (16, 18) to voltage sources. The gate electrode assemblies (16, 18) have gate electrodes (20, 22, 30, 32, 34, 38, 40), which are arranged on a surface (14) of the electronic component (10), for producing potential wells (46, 48, 62, 64, 66) in the substrate (12).

A radio-frequency (RF) to direct current (DC) converter is provided. When a DC electrical current is applied via a DC input port of the converter, the DC electrical current is shunted to ground through a Josephson junction (JJ) of the converter and substantially no DC electrical current flows through a resistor of the converter, and when an RF electrical current is applied via an RF input port of the converter, output trains of SFQ current pulses from a DC to SFQ converter of the RF-to-DC converter with pulse-to-pulse spacing inversely proportional to the RF electrical current frequency cause the JJ to switch at a rate commensurate with an RF frequency of the RF electrical current to generate a steady state voltage across the JJ linearly dependent on the RF frequency.

A radio-frequency (RF) to direct current (DC) converter is provided. When a DC electrical current is applied via a DC input port of the converter, the DC electrical current is shunted to ground through a Josephson junction (JJ) of the converter and substantially no DC electrical current flows through a resistor of the converter, and when an RF electrical current is applied via an RF input port of the converter, output trains of SFQ current pulses from a DC to SFQ converter of the RF-to-DC converter with pulse-to-pulse spacing inversely proportional to the RF electrical current frequency cause the JJ to switch at a rate commensurate with an RF frequency of the RF electrical current to generate a steady state voltage across the JJ linearly dependent on the RF frequency.

A four-terminal-pair AC quantum resistance dissemination bridge and related methods are provided. The bridge includes: a supply transformer IVD1, a Kelvin branch A1, a Wagner branch A0, the first and second current sources A2, A3, an injection inductive voltage divider A4, a ratio transformer IVD2, the first and second four-terminal AC resistor connection points Z1, Z2, chokes H, and null indicators D. An isolated inductive winding LO is wound along the ratio transformer IVD2 and supplies excitation current to primary winding of injection inductive voltage divider A4 to avoid the mutual influence among various balance networks and rapid balance of the bridge can be realized. By changing turn ratio of primary winding L3 and secondary winding L4 of the second inductive voltage divider T2, the phase shift can be realized through only one set of capacitors for imaginary part error compensation, the bridge with multiple frequency points can be obtained.

A four-terminal-pair AC quantum resistance dissemination bridge and related methods are provided. The bridge includes: a supply transformer IVD1, a Kelvin branch A1, a Wagner branch A0, the first and second current sources A2, A3, an injection inductive voltage divider A4, a ratio transformer IVD2, the first and second four-terminal AC resistor connection points Z1, Z2, chokes H, and null indicators D. An isolated inductive winding LO is wound along the ratio transformer IVD2 and supplies excitation current to primary winding of injection inductive voltage divider A4 to avoid the mutual influence among various balance networks and rapid balance of the bridge can be realized. By changing turn ratio of primary winding L3 and secondary winding L4 of the second inductive voltage divider T2, the phase shift can be realized through only one set of capacitors for imaginary part error compensation, the bridge with multiple frequency points can be obtained.

Techniques for designing, creating, and utilizing a current biased tunable qubit are presented. A qubit device can comprise a first Josephson junction (JJ) located along a first current path of the device, and a second JJ and third JJ coupled in series along a second current path in parallel with the first current path, wherein the second and third JJs facilitate controlling frequency of the device. The first JJ can be larger in area than each of the second and third JJs, wherein a current splitting ratio between the first current path and second current path can be increased thereby. The device can comprise a capacitor with a first terminal associated with the second and third JJs, and a second terminal associated with ground. Alternatively, a high kinetic inductance wire can be used in the first current path, instead of the JJ.