International Business Machines Corporation

Hanhee Paik

Martin O Sandberg

Vivekananda P Adiga

Jay Michael Gambetta

Jason Scott Orcutt

Jerry M Chow

Lev Samuel Bishop

Jared Barney Hertzberg

Jae-Woong Nah

Patryk Gumann

Richard Alan Haight

Stefan Filipp

Baleegh Abdo

Sami Rosenblatt

Salvatore Bernardo Olivadese

David C Mckay

Firat Solgun

Ali Afzali-Ardakani

Paul Stephen Andry

Yves Corfield Martin

Douglas Max Gill

Abram L Falk

James Robert Rozen

Chi Xiong

Swetha Kamlapurkar

The invention includes methods, and the structures formed, for multi-qubit chips. The methods may include annealing a Josephson junction of a qubit to either increase or decrease the frequency of the qubit. The conditions of the anneal may be based on historical conditions, and may be chosen to tune each qubit to a desired frequency.

Frequency tuning of multi-qubit systems

A resonator is based on a coplanar waveguide (CPW) structure that includes a first end portion having a first width and configured to be coupled to a first qubit. There is a middle portion having a second width that is narrower than the first width. There is a second end portion having a third width that is wider than the second width and configured to be coupled to a second qubit.

Compact resonator with shifted higher modes for quantum buses

Techniques regarding quantum transducers are provided. For example, one or more embodiments described herein can include an apparatus that can include a superconducting microwave resonator having a microstrip architecture that includes a dielectric layer positioned between a superconducting waveguide and a ground plane. The apparatus can also include an optical resonator positioned within the dielectric layer.

Quantum transducers with embedded optical resonators

Techniques and a system for quantum computing device modeling and design are provided. In one example, a system includes a modeling component and a simulation component. The modeling component models a quantum device element of a quantum computing device as an electromagnetic circuit element to generate electromagnetic circuit data for the quantum computing device. The simulation component simulates the quantum computing device using the electromagnetic circuit data to generate response function data indicative of a response function for the quantum computing device. Additionally or alternatively, a Hamiltonian is constructed based on the response function.

Quantum computing device design

Techniques regarding encapsulating one or more superconducting devices of a quantum processor are provided. For example, one or more embodiments described herein can regard a method that can comprise depositing a metal fluoride layer onto a superconducting resonator and a silicon substrate that can be comprised within a quantum processor. The superconducting resonator can be positioned on the silicon substrate. Also, the metal fluoride layer can coat the superconducting resonator.

Metal fluoride encapsulation of superconducting devices

Systems, devices, computer-implemented methods, and computer program products to facilitate contactless screening of a qubit are provided. According to an embodiment, a system can comprise a memory that stores computer executable components and a processor that executes the computer executable components stored in the memory. The computer executable components can comprise a scanner component that establishes a direct microwave coupling of a scanning probe device to a qubit of a quantum device. The computer executable components can further comprise a parameter extraction component that determines qubit frequency of the qubit based on the direct microwave coupling.

Contactless screening of a qubit

A quantum computer includes a quantum computing system; a transducer disposed inside the quantum computing system, the transducer being configured to receive an optical control propagating wave and output a microwave control propagating wave; and a quantum processor comprising a plurality of qubits, the plurality of qubits being disposed in the quantum computing system, each qubit of the plurality of qubits being configured to receive at least a portion of the microwave control propagating wave to control a quantum state of each qubit of the plurality of qubits.

System and method to control quantum states of microwave frequency qubits with optical signals

A modular superconducting quantum processor includes a first superconducting chip including a first plurality of qubits each having substantially a first resonance frequency and a second plurality of qubits each having substantially a second resonance frequency, the first resonance frequency being different from the second resonance frequency, and a second superconducting chip including a third plurality of qubits each having substantially the first resonance frequency and a fourth plurality of qubits each having substantially the second resonance frequency. The quantum processor further includes an interposer chip connected to the first superconducting chip and to the second superconducting chip. The interposer chip has interposer coupler elements configured to couple the second plurality of qubits to the fourth plurality of qubits.

Modular, frequency-flexible, superconducting quantum processor architecture

A method for improving lifetime and coherence time of a qubit in a quantum mechanical device is provided. The method includes providing a substrate having a frontside and a backside, the frontside having at least one qubit formed thereon, the at least one qubit having capacitor pads. The method further includes at least one of removing an amount of substrate material from the backside of the substrate at an area opposite the at least one qubit or depositing a superconducting metal layer at the backside of the substrate at the area opposite the at least one qubit to reduce radiofrequency electrical current loss due to at least one of silicon-air (SA) interface, metal-air (MA) interface or silicon-metal (SM) interface so as to enhance a lifetime (T1) and a coherence time (T2) in the at least one qubit.

Superconducting qubit lifetime and coherence improvement via backside etching

A qubit includes a substrate, and a first capacitor structure having a lower portion formed on a surface of the substrate and at least one first raised portion extending above the surface of the substrate. The qubit further includes a second capacitor structure having a lower portion formed on the surface of the substrate and at least one second raised portion extending above the surface of the substrate. The first capacitor structure and the second capacitor structure are formed of a superconducting material. The qubit further includes a junction between the first capacitor structure and the second capacitor structure. The junction is disposed at a predetermined distance from the surface of the substrate and has a first end in contact with the first raised portion and a second end in contact with the second raised portion.

Transmon qubits with trenched capacitor structures

Techniques regarding parallel gradiometric SQUIDs and the manufacturing thereof are provided. For example, one or more embodiments described herein can comprise an apparatus, which can comprise a first pattern of superconducting material located on a substrate. Also, the apparatus can comprise a second pattern of superconducting material that can extend across the first pattern of superconducting material at a position. Further, the apparatus can comprise a Josephson junction located at the position, which can comprise an insulating barrier that can connect the first pattern of superconductor material and the second pattern of superconductor material.

Gradiometric parallel superconducting quantum interface device

In an embodiment, a quantum device includes an interposer layer comprising a set of vias. In an embodiment, the quantum device includes a dielectric layer formed on a first side of the interposer, the dielectric layer including a set of transmission lines communicatively coupled to the set of vias. In an embodiment, the quantum device includes a plurality of qubit chips coupled to an opposite side of the interposer layer, each qubit chip of the plurality of qubit chips including: a plurality of qubits on a first side of the qubit chip and a plurality of protrusions on a second side of the qubit chip. In an embodiment, the quantum device includes a heat sink thermally coupled with the plurality of qubit chips, the heat sink comprising a plurality of recesses aligned with the plurality of protrusions of the plurality of qubit chips.

Flip chip assembly of quantum computing devices

Techniques regarding encapsulating one or more superconducting devices of a quantum processor are provided. For example, one or more embodiments described herein can regard a method that can comprise depositing an adhesion layer onto a superconducting resonator and a silicon substrate that are comprised within a quantum processor. The superconducting resonator can be positioned on the silicon substrate. Also, the adhesion layer can comprise a chemical compound having a thiol functional group.

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Danbury, CT, United States of America

Hanhee Paik