Auxiliary-Qubit Leakage Transfer for Quantum State Recovery

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Quantum computing systems face challenges in reducing qubit leakage errors, which occur when higher energy levels become excited due to gate operations or system-environment interactions, and cannot be corrected by typical quantum error correction methods.

Innovation Solution

An arrangement comprising a first qubit, a second qubit, and energy dissipation structures selectively couplable to each qubit, with a control unit performing quantum operations to transfer properties between qubits and couple them to energy dissipation structures for energy dissipation, thereby reducing leakage errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If typical quantum error correction methods are used, then errors within the computational basis can be corrected, but leakage errors to higher energy levels cannot be fixed

Engineering Contradiction:
Improveerror correction capabilityVSAvoidapplicability to leakage errors
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an auxiliary qubit as an intermediary system between the computational qubit and the energy dissipation structure. The auxiliary qubit receives leakage errors from the computational qubit through quantum operations, then transfers these errors to the energy dissipation structure, enabling indirect correction of leakage errors that typical quantum error correction cannot handle directly

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The error correction function is segmented into two distinct components: the computational qubit that maintains quantum information and the auxiliary qubit that handles leakage errors. This segmentation allows the system to address different types of errors through specialized mechanisms, with the auxiliary qubit specifically dedicated to managing non-computational state population

Inventive Principle:
Principle #1Segmentation

2Productivity

If gate operations are applied to qubits, then quantum computations can be performed, but leakage errors occur due to excitation to higher energy levels

Engineering Contradiction:
Improvequantum computation capabilityVSAvoidqubit state accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent converts the harmful leakage errors (population in non-computational states) into a transferable quantum state property. By using quantum operations to move the leakage population to an auxiliary qubit and then to an energy dissipation structure, the system transforms an uncorrectable error into a manageable and removable condition, improving overall computational reliability

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system performs preliminary error management by continuously monitoring and transferring leakage errors as they occur during quantum operations. Rather than waiting for errors to accumulate, the auxiliary qubit and energy dissipation structure actively prevent leakage population from compromising the computational qubit's accuracy

Inventive Principle:
Principle #10Preliminary action

3Reliability

If energy dissipation structures are coupled to qubits, then leakage errors are reduced, but system complexity increases

Engineering Contradiction:
Improveleakage error reductionVSAvoidquantum system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The auxiliary qubit serves as a mediator that simplifies the coupling between the computational qubit and the energy dissipation structure. Instead of directly coupling multiple dissipation structures to each qubit, the auxiliary qubit acts as an intermediate buffer, reducing the overall system complexity while maintaining effective leakage error reduction

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The auxiliary qubit performs multiple functions: it receives leakage errors from computational qubits, transfers them to energy dissipation structures, and can be initialized to ground states. This multi-functionality reduces the need for separate dedicated components for each error correction task, thereby reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach efficiently reduces the population of non-computational states in qubits, minimizing leakage errors and maintaining the accuracy of quantum computations.

Implementation Method 1

The first energy dissipation structure and/or the second energy dissipation structure is configured to dissipate photon energy transferred to the energy dissipation structure via photon-assisted electron tunnelling in the NIS/SINIS junction

Methodology Applied
Scientific EffectPhoton-assisted electron tunnelling:

Data Source

PatentEP3937092A1Qubit leakage error reduction
Publication Date: 2022.01.12 IQM FINLAND OY
  • EP3937092A1 patent drawingFigure 1~2
  • EP3937092A1 patent drawingFigure 3~5
  • EP3937092A1 patent drawingFigure 6

AI summary

It is an objective to provide an arrangement for reducing qubit leakage errors in quantum computing system. According to an embodiment, an arrangement for reducing qubit leakage errors comprises a first qubit and a second qubit selectively couplable to each other. The arrangement may further comprise a first energy dissipation structure selectively couplable to the first qubit, wherein the first energy dissipation structure is configured to dissipate energy transferred to the first energy dissipation structure. The arrangement may further comprise a control unit configured to: perform a first quantum operation to transfer at least one property of a quantum state from the first qubit to the second qubit; couple the first qubit to the first energy dissipation structure for a time interval; and perform a second quantum operation to transfer the at least one property of the quantum state from the second qubit to the first qubit after the time interval.