Superconducting Qubit Drive Biasing for ZZ Interaction Cancellation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In quantum computing, there is a competition between increasing the exchange coupling strength for faster two-qubit gates and minimizing the spurious ZZ interaction, which degrades circuit performance due to idle gate errors and multi-qubit infidelity.

Innovation Solution

A quantum device with a biasing component operatively coupled to qubits via drive lines, using continuous wave (CW) tones to dynamically control ZZ interactions by adjusting the relative phase difference or amplitude of the drive tones, thereby canceling or reducing static ZZ interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the exchange coupling strength J is increased to speed up two-qubit gates, then the gate speed increases, but the spurious ZZ interaction increases causing idle gate errors and multi-qubit circuit infidelity

Engineering Contradiction:

Improvetwo-qubit gate speedVSAvoidcircuit fidelity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by introducing a compensating microwave drive that generates an opposite ZZ interaction to cancel the spurious coupling. The compensating drive is configured with specific amplitude and phase to produce a ZZ interaction that opposes and neutralizes the harmful static ZZ coupling, thereby eliminating idle gate errors while preserving the desired exchange coupling for fast two-qubit gates

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent employs parameter changes by dynamically adjusting the amplitude and phase of the compensating microwave drive based on the operating conditions. By tuning these parameters, the system optimizes the cancellation of ZZ interactions across different gate operations, maintaining high fidelity while enabling fast gate speeds through strong exchange coupling

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the exchange coupling strength J is increased to improve entanglement rates, then the entanglement speed increases, but the spurious ZZ interaction increases causing idle gate errors

Engineering Contradiction:

Improveentanglement rateVSAvoidspurious ZZ interaction

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful spurious ZZ interaction into a beneficial effect by using it as the basis for the compensating drive. The same physical mechanism that causes the harmful interaction (exchange coupling) is harnessed to generate the compensating ZZ interaction, turning the problem into a solution. The compensating drive leverages the existing coupling to create an opposite effect that cancels the harm while preserving the useful entanglement generation

Inventive Principle:

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

Data Source

PatentUS11625638B2Drive enhanced J/ZZ operation for superconducting qubits

Publication Date: 2023.04.11 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Systems, devices, computer-implemented methods, and/or computer program products that facilitate dynamic control of ZZ interactions for quantum computing devices. In one example, a quantum device can comprise a biasing component that is operatively coupled to first and second qubits via respective first and second drive lines. The biasing component can facilitate dynamic control of ZZ interactions between the first and second qubits using continuous wave (CW) tones applied via the respective first and second drive lines.