Voltage-Biased EMI Shield for Ion Trap Cross-Talk Control

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Solution Overview

Problem

Ion trap quantum computers face issues with electromagnetic interference (EMI) shields causing cross-talk with photon detectors, leading to ion heating and computational errors, while conventional EMI shields also disrupt ion positions and signal detection.

Innovation Solution

Implement a voltage-biased EMI shield that is electrically invisible to the ions by setting its bias voltage to the electrical potential of the ion positions, allowing the shield to be situated closer to the ions without influencing their position, thus reducing cross-talk and enhancing photon detection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional EMI shield is placed between the photon detector and ion trap, then electromagnetic interference is reduced, but the shield disrupts ion positions and causes ion heating

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidion position stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The EMI shield is biased with a voltage that matches the electrical potential at the ion positions, changing the electrical parameter of the shield to make it electrically invisible to the ions. This resolves the contradiction by allowing the shield to block EMI without disrupting ion positions or causing heating.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The shield is positioned and voltage-biased to be at the same electrical potential as the ion positions, creating an equipotential condition. This eliminates electric field disturbances that would otherwise cause ion heating and position disruption, while still providing EMI shielding.

Inventive Principle:
Principle #12Equipotentiality

2Object-affected harmful factors

If the EMI shield is placed closer to the ions to improve shielding effectiveness, then cross-talk is reduced, but the shield's influence on ion positions increases

Engineering Contradiction:
Improvecross-talkVSAvoidshield-to-ion distance
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

By changing the voltage parameter of the EMI shield to match the electrical potential at ion positions, the shield can be placed closer to the ions without increasing its influence on ion positions. The voltage bias makes the shield electrically invisible, eliminating the trade-off between shielding effectiveness and distance.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the EMI shield is used to reduce electromagnetic interference, then detection accuracy is improved, but ion heating occurs leading to computational errors

Engineering Contradiction:
Improvephoton detection accuracyVSAvoidion temperature
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The EMI shield is voltage-biased to match the electrical potential at ion positions, creating an equipotential condition that eliminates electric field disturbances. This prevents ion heating while maintaining EMI shielding, thereby improving photon detection accuracy without causing computational errors.

Inventive Principle:
Principle #12Equipotentiality

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 voltage-biased EMI shield preserves the quantum state of ions, ensuring accurate computational processes by minimizing disturbances and improving detection rates.

Implementation Method 1

an electromagnetic interference (EMI) shield disposed between the ion trap and the photon detector

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

the EMI shield is voltage-biased to a voltage that corresponds to an electrical potential at positions of the ions in the ion trap without the EMI shield present

Methodology Applied
Scientific EffectElectrostatic potential: Electric Field

Data Source

PatentEP4641453A1Biased electromagnetic interference shield for ion trap of a quantum computer
Publication Date: 2025.10.29 NXP USA INC
  • EP4641453A1 patent drawingFigure 1
  • EP4641453A1 patent drawingFigure 2
  • EP4641453A1 patent drawingFigure 3

AI summary

A quantum computer includes an ion trap, a photon detector, and an electromagnetic interference (EMI) shield. The EMI shield is disposed between the ion trap and the photon detector and is configured to be biased by at least one voltage. In at least some implementations, the at least one voltage is a single voltage applied to the EMI shield as a whole. In other implementations, the EMI shield includes a plurality of segments and the at least one voltage includes a plurality of voltages, each applied to a different segment of the plurality of segments.