Gate Voltage-Tunable Electron System for Superconducting Resonator

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing quantum computing architectures face performance degradation due to microwave cross-talk and frequency collisions between qubits during readout, which are not effectively addressed by flux-tunable qubits that suffer from reduced coherence times and susceptibility to cross-talk and heating.

Innovation Solution

A gate voltage-tunable electron system integrated with a superconducting resonator is used to form a Josephson junction switch, allowing for tunable coupling between qubits by varying the critical current and inductance of the switch, thereby controlling the characteristic frequency of the resonator and reducing unwanted coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flux-tunable qubits are used to control qubit coupling, then qubit coupling can be adjusted, but coherence times are reduced and susceptibility to cross-talk and heating increases

Engineering Contradiction:
Improvequbit coupling controlVSAvoidcoherence time
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces flux-tunable qubits (which use magnetic flux control) with a gate voltage-tunable electron system that uses electric field control via a gate electrode. This substitution of control mechanism eliminates the need for flux tuning while achieving the same qubit coupling control function, thereby improving coherence times and reducing susceptibility to cross-talk and heating.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a gate electrode as an intermediary control element that applies voltage to tune the electron system's properties. This intermediary allows for precise control of qubit coupling through voltage adjustment without directly manipulating the qubits with flux, thus maintaining reliability while achieving adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If flux-tunable qubits are used to control qubit coupling, then qubit coupling can be adjusted, but susceptibility to microwave cross-talk increases

Engineering Contradiction:
Improvequbit coupling controlVSAvoidmicrowave cross-talk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces flux-tunable qubits with a gate voltage-tunable electron system integrated with a superconducting resonator. This substitution changes the control mechanism from magnetic flux to electric field, which reduces susceptibility to microwave cross-talk while maintaining the ability to adjust qubit coupling through gate voltage control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If flux-tunable qubits are used to control qubit coupling, then qubit coupling can be adjusted, but heating increases

Engineering Contradiction:
Improvequbit coupling controlVSAvoidheating
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent substitutes flux-tunable qubits with a gate voltage-tunable electron system that uses electric field control instead of magnetic flux control. This substitution eliminates the heating effect associated with flux tuning while preserving the ability to control qubit coupling through voltage adjustment, thereby reducing temperature increase.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Object-affected harmful factors

If gate voltage-tunable electron system is integrated with superconducting resonator, then microwave cross-talk and frequency collisions are reduced, but device complexity increases

Engineering Contradiction:
Improvemicrowave cross-talkVSAvoiddevice structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the gate voltage-tunable electron system with the superconducting resonator into an integrated structure. This combination achieves the dual benefit of reducing microwave cross-talk and frequency collisions while managing device complexity through unified design, where the resonator serves both as a coupling element and a frequency-tuning component.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables reduced microwave cross-talk and frequency collisions, improving qubit coherence times and enabling faster, more precise control over qubit coupling, with the ability to shut off or reduce coupling of qubits with unwanted transition frequencies.

Implementation Method 1

A gate voltage-tunable electron system integrated with a superconducting resonator is used to form a Josephson junction switch, allowing for tunable coupling between qubits by varying the critical current and inductance of the switch

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Implementation Method 2

the gate varying an inductance of the electron system, thereby varying a characteristic frequency of the resonator structure

Methodology Applied
Scientific EffectInductance modulation: Electromagnetic Induction

Data Source

PatentEP3948697B1Gate voltage-tunable electron system integrated with superconducting resonator for quantum computing device
Publication Date: 2024.10.02 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • EP3948697B1 patent drawingFigure 1
  • EP3948697B1 patent drawingFigure 2
  • EP3948697B1 patent drawingFigure 3

AI summary

A superconducting coupling device includes a resonator structure. The resonator structure has a first end configured to be coupled to a first device and a second end configured to be coupled to a second device. The device further includes an electron system coupled to the resonator structure, and a gate positioned proximal to a portion of the electron system. The electron system and the gate are configured to interrupt the resonator structure at one or more predetermined locations forming a switch. The gate is configured to receive a gate voltage and vary an inductance of the electron system based upon the gate voltage. The varying of the inductance induces the resonator structure to vary a strength of coupling between the first device and the second device.