Superconducting Resonator Thermometry for Cryogenic Qubit Stability

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Solution Overview

Problem

Determining the temperature of superconducting quantum computing devices is challenging due to the properties of these devices, which affect conventional thermodynamic measurement methods, and is crucial for maximizing the longevity of superconductive qubits by maintaining thermal energy below quantum energy levels.

Innovation Solution

A system and method using superconducting resonators to measure temperature by simulating operation at a reference temperature, measuring operating frequency, and determining temperature based on frequency shifts due to kinetic inductance changes, employing computer-implemented components and cloud computing environments for autonomous and efficient temperature determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional thermodynamic means (conduction, convection, radiation) are used to measure temperature, then temperature measurement is achieved, but the quantum computing device operation is affected and measurement precision is insufficient due to device properties

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidquantum computing device operation stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a superconducting resonator as an intermediary element that couples to the quantum computing device. The resonator measures temperature through its kinetic inductance properties without directly interfering with the quantum device operation. The resonator's resonant frequency shifts in response to temperature changes, providing a non-intrusive measurement mechanism that maintains quantum device stability while achieving precise temperature determination.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of stationary object

If thermal energy is reduced to maximize qubit longevity, then qubit longevity is improved, but temperature measurement becomes more difficult due to lower thermal signals

Engineering Contradiction:
Improvequbit longevityVSAvoidtemperature measurement difficulty
Core Design Contradiction:
Duration of action of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The patent exploits the temperature-dependent kinetic inductance parameter of superconducting materials. By measuring changes in the resonator's resonant frequency, which is directly related to kinetic inductance, the system can detect temperature variations even at cryogenic temperatures where thermal energy is minimal. This parameter-based measurement approach enables accurate temperature sensing without requiring high thermal signals, thus maintaining both qubit longevity and measurement capability.

Inventive Principle:
Principle #35Parameter changes

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

Enables accurate and autonomous temperature measurement of superconducting quantum devices, improving the longevity of qubits by effectively managing thermal energy levels through precise frequency analysis.

Implementation Method 1

measuring an operating frequency exhibited by the one or more superconducting resonators during operation of the one or more quantum computing devices. The temperature can then be determined based on a frequency shift exhibited by the one or more superconducting resonators due to a change in kinetic inductance with a change in temperature.

Methodology Applied
Scientific EffectKinetic inductance:

Implementation Method 2

A system and method using superconducting resonators to measure temperature by simulating operation at a reference temperature, measuring operating frequency, and determining temperature based on frequency shifts due to kinetic inductance changes

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP3983771B1On-chip thermometer for superconducting quantum computing devices
Publication Date: 2024.01.10 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • EP3983771B1 patent drawingFigure 1
  • EP3983771B1 patent drawingFigure 2
  • EP3983771B1 patent drawingFigure 3

AI summary

Techniques regarding determining the temperature of one or more quantum computing devices are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a temperature component that can determine a temperature of a superconducting resonator based on a frequency shift exhibited by the superconducting resonator due to a change in kinetic inductance with a change in temperature.