International Business Machines Corporation

Martin O Sandberg

Vivekananda P Adiga

Hanhee Paik

Jerry M Chow

Jason Scott Orcutt

Sami Rosenblatt

Markus Brink

Jared Barney Hertzberg

Jay Michael Gambetta

Rasit Onur Topaloglu

Richard Alan Haight

Patryk Gumann

Salvatore Bernardo Olivadese

Douglas Max Gill

Firat Solgun

Keith E Fogel

Ali Afzali-Ardakani

Jeng-Bang Yau

Yves Corfield Martin

David Lee Rath

Dongbing Shao

David C Mckay

Nicholas Torleiv Bronn

John Bruley

Harry Jonathon Mamin

Benjamin B Wymore

Robert Connelly

Devendra K Sadana

Steven J Holmes

Oleg Gluschenkov

Kenneth Parker Rodbell

Jae-Woong Nah

Paul Stephen Andry

Bucknell Chapman Webb

Elbert Emin Huang

Li-Wen Hung

Hongwen Yan

Eric Peter Lewandowski

Ali Afzali-ardakani

James Robert Rozen

Daniel Rugar

Oblesh Jinka

Yasir Sulehria

Marinus Johannes Petrus Hopstaken

Antoine Hervier

Cihan Kurter

Joseph Finley

Adiga Vivekananda

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 method for adjusting a resonance frequency of a qubit in a quantum mechanical device includes providing a substrate having a frontside and a backside, the frontside having at least one qubit formed thereon, the at least one qubit comprising capacitor pads; and removing substrate material from the backside of the substrate at an area opposite the at least one qubit to alter a capacitance around the at least one qubit so as to adjust a resonance frequency of the at least one qubit.

Superconducting qubit capacitance and frequency of operation tuning

One or more systems, devices, methods of use and/or methods of fabrication provided herein relate to a superconducting device that can be operated with minimal electric field energy coupling at surface layers of the superconducting device and/or that can have a small footprint. According to one embodiment, a device can comprise a Josephson junction located between a first capacitor portion and a second capacitor portion of a capacitor, wherein at least a trenched section of the first capacitor portion is located beneath a surface of a substrate, and wherein at least a trenched section of the second capacitor portion is located beneath the surface of the substrate. According to another embodiment, a device can comprise a capacitor disposed within a substrate layer and the capacitor comprising a pair of material-filled trenches in the substrate layer, and a Josephson junction coupled to the capacitor.

Quantum circuit with trench capacitor

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

Devices, systems, methods, and/or computer-implemented methods that can facilitate protection of a substrate in a qubit device using sacrificial material are provided. According to an embodiment, a device can comprise a superconducting lead provided on a pillar of a sacrificial material provided on a substrate. The device can further comprise a collapsed superconducting junction provided on the substrate and coupled to the superconducting lead.

Sacrificial material facilitating protection of a substrate in a qubit device

A Josephson Junction qubit device is provided. The device includes a substrate of silicon material. The device includes first and second electrodes of superconducting metal. The device may include a nanowire created by direct ion implantation on to the silicon material to connect the first and second electrodes. The device may include first and second superconducting regions created by direct ion implantation on to the silicon material, the first superconducting region connecting the first electrode and the second superconducting region connecting the second electrode, with a silicon channel formed by a gap between the first and second superconducting regions.

Josephson junction device fabricated by direct write ion implantation

Devices, systems, and/or methods that can facilitate local heating of a superconducting flux biasing loop are provided. According to an embodiment, a device can comprise a substrate having a superconducting flux bias circuit comprising a biasing loop coupled to a flux controlled qubit device. The device can further comprise a heating device coupled to the biasing loop.

Flux bias line local heating device

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

Devices, systems, and/or methods that can facilitate local heating of a superconducting flux biasing loop are provided. According to an embodiment, a method can comprise forming on a substrate a biasing loop and a flux controlled qubit device of a superconducting flux bias circuit. The method can further comprise forming a heating device on the substrate to couple the heating device to the biasing loop.

Fabrication of a flux bias line local heating device

Devices, methods, and/or computer-implemented methods that can facilitate formation of a self assembled monolayer on a quantum device are provided. According to an embodiment, a device can comprise a qubit formed on a substrate. The device can further comprise a self assembled monolayer formed on the qubit.

Self assembled monolayer formed on a quantum device

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 and techniques that facilitate spurious junction prevention via in-situ ion milling are provided. In various embodiments, a method can comprise forming a tunnel barrier of a Josephson junction on a substrate during a shadow evaporation process. In various instances, the method can further comprise etching an exposed portion of the tunnel barrier during the shadow evaporation process. In various embodiments, the shadow evaporation process can comprise patterning a resist stack onto the substrate. In various instances, the etching the exposed portion of the tunnel barrier can leave a protected portion of the tunnel barrier within a shadow of the resist stack. In various instances, the shadow of the resist stack can be based on a direction of the etching the exposed portion of the tunnel barrier. In various embodiments, the shadow evaporation process can further comprise depositing a first superconducting material on the substrate after the patterning the resist stack, oxidizing a surface of the first superconducting material to form the tunnel barrier, and depositing a second superconducting material over the protected portion of the tunnel barrier to form a Josephson junction. In various instances, the etching the exposed portion of the tunnel barrier can occur after the oxidizing the surface of the first superconducting material and before the depositing the second superconducting material.

Spurious junction prevention via in-situ ion milling

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

Circuits and methods of operation that can facilitate reducing surface losses for quantum devices are provided. In one example, a quantum device can comprise a dielectric layer, a first electrode, and a second electrode. The dielectric layer can comprise a recess formed in a surface of the dielectric layer that reduces a thickness of the dielectric layer from a first thickness external to a footprint of the recess to a second thickness within the footprint of the recess. The second thickness can be less than the first thickness. The first electrode can be positioned within the footprint of the recess. The second electrode can be electrically isolated from the first electrode by the dielectric layer. The first and second electrodes can be positioned on opposing surfaces of the dielectric layer.

Quantum device with low surface losses

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Ossining, NY, United States of America

Martin O Sandberg