International Business Machines Corporation

Timothy Phung

Aakash Pushp

Jiri Stehlik

David Zajac

Devin L Underwood

David William Abraham

Martin Michael Frank

Russell Alan Budd

Jason Scott Orcutt

Masatoshi Ishii

Vivekananda P Adiga

Charles Thomas Rettner

David James Frank

Jin Ping Han

Harry Jonathon Mamin

Chirag Garg

Muir Kumph

Stuart P Parkin

Moein Malekakhlagh

Devin Underwood

Stuart Sp Parkin

One or more systems, devices, methods of use and/or methods of fabrication provided herein relate to a quantum computing device that can operated to have 1order insensitivity to flux noise. According to one embodiment, a device comprises a flux tunable qubit capacitively coupled to a flux tunable bus. According to another embodiment, a device comprises a flux tunable qubit capacitively coupled to a flux tunable bus, wherein the flux tunable bus is capacitively coupled a fixed frequency qubit.

Flux control architecture for 1st order noise insensitivity

A modular electronic structure includes a first chip having a first interleaved portion and a first electromagnetic coupler on the first interleaved portion. There is a second chip having a second interleaved portion and a second electromagnetic coupler on the second interleaved portion and configured to electromagnetically couple with the first electromagnetic coupler. The first interleaved portion fits between two surfaces of the second chip. The second interleaved portion fits between two surfaces of the first chip.

Mechanically tolerant couplers

Systems and techniques that facilitate enabling transfer of a quantum state between a quantum device and a microwave resonator of a microwave optical transducer. In various embodiments, a system can comprise a quantum device, a microwave optical transducer including a microwave resonator, and a coherent interconnect. In various embodiments, the coherent interconnect can be between the quantum device and the microwave optical transducer that can enable bi-directional transfer of a quantum state between the quantum device and the microwave resonator. In various embodiments, the microwave optical transducer can be separately packaged from the quantum device. With various embodiments, the coherent interconnect can be a superconducting coaxial cable.

Coherent interconnects between superconducting qubits and microwave-optical transducers

Systems and techniques that facilitate trimmable inductors for qubit frequency tuning are provided. In various embodiments, a device can comprise a Josephson junction. In various aspects, the Josephson junction can be shunted by a capacitor, and a trimmable inductor can couple the Josephson junction to a pad of the capacitor. In various cases, the trimmable inductor can comprise a first conductive path that includes a severable and/or weldable superconducting bridge and a second conductive path that is in parallel with the first conductive path. In various aspects, severing and/or welding the severable and/or weldable superconducting bridge can controllably change an inductance of the trimmable inductor, which can commensurately change a resonant frequency of a qubit formed by the Josephson junction and the capacitor.

Trimmable inductors for qubit frequency tuning

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.

Current biased tunable qubit

One or more systems, devices, and/or methods of manufacture and/or use provided herein relate to a quantum computing process to achieve higher connectivity of qubits to more than nearest neighbors and/or to a plurality of nearest neighbors. A system can comprise a tunable first coupler coupled to a first qubit, a tunable second coupler coupled to a second qubit, and a junction coupling the first coupler and the second coupler being both parametrically drivable. The first coupler and the second coupler can comprise superconducting quantum interference devices or Josephson junctions. The junction can comprise a central hub or central node separately coupled to the first coupler and the second coupler. The first coupler and the second coupler can be configured to capacitively or inductively couple the first qubit and the second qubit to one another to perform a control-Z (CZ) gate or an iSWAP gate.

High connectivity parametric gate

Systems and techniques that facilitate mitigation of baseband pulse distortion via radiofrequency-to-baseband conversion are provided. In various embodiments, a system can comprise a qubit. In various aspects, the system can further comprise a signal generator that can produce a radiofrequency signal. In various instances, the system can further comprise a signal converter coupled between the qubit and the signal generator. In various cases, the signal converter can convert the radiofrequency signal into a baseband signal. In various aspects, such radiofrequency-to-baseband conversion can reduce a dispersion-induced distortion associated with driving the qubit.

Mitigating baseband pulse dispersion via radiofrequency-to-baseband conversion

Techniques for creating a low pass filter associated with a flux line are presented. A qubit device can comprise a first substrate and second substrate. A low pass filter, comprising at least one inductor and at least one capacitor can be formed, wherein respective components of or associated with the low pass filter can be formed on the first or second substrates, and wherein one or more bump bonds can extend between the substrates to connect respective components that are on respective substrates. The filter can receive an input signal via an input line and filter the signal to produce a filtered signal as output to a flux line that is in proximity to a coupler with SQUID loop and one or more flux-tunable qubits that are formed on one of the substrates. The filter can reduce electrical noise and Purcell decay associated with the flux line.

Flux line filter

Techniques for creating an offset embedded ground plane cutout for a qubit device to facilitate frequency tuning of the qubit device are presented. A qubit device can comprise a first substrate and second substrate in a flip-chip assembly. The qubit chip assembly can comprise a qubit component fabricated on the first substrate. The qubit component can comprise a Josephson junction (JJ) circuit that can be offset from a center point of the qubit component. The qubit chip assembly can comprise an embedded ground plane situated on a surface of the qubit chip assembly. A cutout section can be formed in the ground plane and positioned over the JJ circuit. The cutout section can enable access of an optical signal or magnetic flux to the JJ circuit. A frequency of the qubit component can be tuned based on application of the optical signal or magnetic flux to the JJ circuit.

Offset embedded ground plane cutout

A three-terminal device is disclosed having a magnetic tunnel junction (MTJ) and a spin orbit torque (SOT) generating layer. The MTJ has a first magnetic layer, a tunnel barrier layer underlying the first magnetic layer, and a second magnetic layer underlying the tunnel barrier, wherein the SOT generating layer is directly underlying the second magnetic layer. The second magnetic layer has a shape that is non-symmetrical, such that an average magnetization of a remnant state associated with the second magnetic layer has an in-plane component that is orthogonal to a current direction in the SOT generating layer.

Control of switching trajectory in spin orbit torque devices by micromagnetic configuration

A tunable resistance device and methods of forming the same include a magnetic fixed layer having a fixed magnetization, a magnetic free layer, and a non-magnetic conductive layer directly between the magnetic fixed layer and the magnetic free layer. The magnetic fixed layer, the magnetic free layer, and the non-magnetic conductive layer are formed in a lattice of wires, with each wire in the lattice being formed from a stack of the magnetic fixed layer, the magnetic free layer, and the non-magnetic conductive layer.

Racetrack synapse for neuromorphic applications

Thermal-spin-torque (TST) in a magnetic tunnel junction (MTJ) is demonstrated by generating large temperature gradients across ultrathin MgO tunnel barriers, with this TST being significant enough to considerably affect the magnitude of the switching field of the MTJ. The origin of the TST is attributed to an asymmetry of the tunneling conductance across the zero-bias voltage of the MTJ. Through magneto-Seebeck voltage measurements, it is estimated that the charge-current that would be generated due to the temperature gradient would give rise to spin-transfer-torque (STT) that is a thousand times too small to account for the observed changes in switching fields, indicating the presence of large TST.

Magnetic tunnel junction switching assisted by temperature-gradient induced spin torque

A domain wall injector device uses electrical current passed across an interface between two magnetic regions whose magnetizations are aligned non-collinearly to create a domain wall or a series of domain walls in one of the magnetic regions. The method relies on a combination of innate fringing fields from the magnetic regions and the spin-transfer torque derived from the charge current. The device may be used to store data that are subsequently read out.

Growing community of inventors

Milpitas, CA, United States of America

Timothy Phung