Superconducting Qubit Circuits With Tunable Noise Protection

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Solution Overview

Problem

Existing superconducting qubit designs are prone to noise and lack precise control over noise reduction properties versus system structure, leading to limitations in noise protection.

Innovation Solution

A systematic construction of a superconducting circuit is developed to implement homological quantum rotor codes, which are noise-protected qubits or qudits, by using a method that involves selecting initial matrices Hx and Hz with specific entries, and placing capacitors, inductances, and Josephson Junctions to enforce error correction constraints, resulting in a circuit with tunable noise protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional superconducting qubit designs are used, then the system is simpler to implement, but the qubits are prone to noise and lack intrinsic robustness

Engineering Contradiction:
Improvenoise protectionVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The qubit is segmented into multiple physical components (Josephson junctions, capacitors, inductors) arranged in specific topologies such as current mirrors or 0-π configurations. This segmentation allows the system to distribute and protect quantum information across multiple elements, providing intrinsic noise protection while maintaining a structured circuit design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements nested protective structures where multiple layers of noise protection are embedded within the qubit architecture. For example, current mirror qubits use nested current paths and 0-π qubits use nested Josephson junction configurations, creating redundant protective mechanisms that enhance reliability without excessive complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If existing protected qubit designs like Kitaev's current mirror or 0-π qubit are used, then some noise protection is achieved, but precise control over noise reduction properties versus system structure is limited

Engineering Contradiction:
Improvenoise protectionVSAvoidcontrol over noise reduction properties
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control mechanisms that allow the noise protection properties to be adjusted based on system requirements. By incorporating controllable elements and adaptive circuit configurations, the system can dynamically tune its noise reduction characteristics, enabling precise control over the balance between protection level and system structure

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes in circuit elements (capacitance values, inductance values, Josephson junction characteristics) to control noise reduction properties. By systematically varying these parameters, the system achieves precise control over noise protection levels while maintaining adaptability to different operational requirements

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the system size is increased in conventional designs, then more qubits are available for computation, but noise protection does not necessarily improve

Engineering Contradiction:
Improvenumber of qubitsVSAvoidnoise protection
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent merges multiple physical components into unified protected qubit structures where the noise protection mechanism is intrinsic to the qubit itself rather than requiring additional separate error correction components. This merging allows the system to scale the number of qubits while each qubit maintains its own noise protection, preventing the degradation of reliability as system size increases

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

The solution provides a concrete implementation of superconducting qubits with intrinsic robustness to noise, offering higher protection against flux noise and allowing for tunable levels of protection through circuit size and layout.

Implementation Method 1

one of them being the well-known transmon consisting in a Josephson junction in parallel with a large capacitor

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Implementation Method 2

Quantum computation is defined as quantum circuits acting on qubits or qudits. The realization of controllable qubits - for quantum bits - using superconducting circuit

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP4654092A1Protected superconducting qubits from homological quantum rotor codes
Publication Date: 2025.11.26 INRIA INSTITUT NATIONAL DE RECHERCHE EN INFORMATIQUE ET EN AUTOMATIQUE
  • EP4654092A1 patent drawingFigure 1
  • EP4654092A1 patent drawingFigure 2
  • EP4654092A1 patent drawingFigure 3~4

AI summary

Method of designing a superconducting circuit for implementing noise-protected qubits, the method, for a predefined number of ordered quantum rotors, comprising selecting two initial matrices Hx and Hz of an identical number of columns equal to the number of quantum rotors, having all entries in a group such as {-1, 0, +1}, and with HXHZT = 0, and implementing a code to build a circuit based on the matrices.