Quantum Bit Coupler Layout for Crosstalk-Suppressed Entanglement

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Solution Overview

Problem

Unwanted crosstalk between superconducting qubits in quantum computing systems, particularly in high-density quantum processors, adversely affects the fidelity of quantum gate operations and entanglement, making it challenging to scale the systems effectively.

Innovation Solution

The use of superconducting quantum bit couplers, such as flux-tunable transmon qubits and transmission line resonators, to control and suppress crosstalk between data and auxiliary qubits, enabling strong exchange coupling and entanglement while minimizing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If superconducting qubits are placed in high-density quantum processors to increase integration density, then the number of qubits and processing capability increase, but unwanted crosstalk between adjacent qubits increases and adversely affects gate operation fidelity

Engineering Contradiction:

Improvequantum processing capabilityVSAvoidcrosstalk between qubits

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces auxiliary quantum bits as intermediary elements between data qubits to mediate interactions. These auxiliary qubits enable controlled coupling between data qubits while suppressing direct unwanted crosstalk, allowing high-density qubit placement without sacrificing gate fidelity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the quantum processor into distinct functional groups: data qubits for computation and auxiliary qubits for mediation and error correction. This segmentation allows independent optimization of each group's function while managing their interactions through controlled coupling mechanisms.

Inventive Principle:

Principle #1Segmentation

2Reliability

If auxiliary quantum bits are coupled to multiple data quantum bits to enable quantum error correction, then error correction capability is provided, but crosstalk between data quantum bits coupled to the same auxiliary quantum bit increases

Engineering Contradiction:

Improvequantum error correctionVSAvoidcrosstalk between data qubits

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic coupling where auxiliary qubits are selectively coupled to data qubits only during specific time intervals when error correction operations are performed. During non-operational periods, the coupling is suppressed, preventing continuous crosstalk while maintaining error correction capability when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent implements dynamically controllable coupling between auxiliary and data qubits, allowing the system to switch between coupled and decoupled states. This dynamic control enables the system to minimize crosstalk during idle periods while enabling strong interactions during error correction operations.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12555017B2Coupling data quantum bits to auxiliary quantum bits

Publication Date: 2026.02.17 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A device comprises a data quantum bit, a first quantum bit coupler, a second quantum bit coupler, and an auxiliary quantum bit. The first quantum bit coupler is coupled to the data quantum bit. The second quantum bit coupler is coupled to the first quantum bit coupler. The auxiliary quantum bit is coupled to the second quantum bit coupler. The first quantum bit coupler is configured to operate in a state to suppress interaction between the data quantum bit and the auxiliary quantum bit. The first quantum bit coupler and the second quantum bit coupler are each configured to operate in a respective state to enable interaction between the data quantum bit and the auxiliary quantum bit and entangle a state of the data quantum bit with a state of the auxiliary quantum bit.