Neutral Atom Qubit Imaging via Intermediary State Transfer

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Solution Overview

Problem

Current methods for imaging neutral atoms in quantum computers, particularly after analog quantum computation, are destructive and time-consuming, leading to significant atom loss and low repetition rates for quantum computation cycles.

Innovation Solution

A method involving the use of multiple laser beams to transfer neutral atoms between different energy states, allowing for non-destructive imaging by detecting photons emitted during spontaneous emission, thereby reducing atom loss and improving computation cycle efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If destructive readout using tweezers is used to identify Rydberg excitations, then the states of neutral atoms can be obtained, but significant atom loss occurs and preparation time increases

Engineering Contradiction:
Improvestate detection accuracyVSAvoidatom loss
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent introduces an intermediary state (a long-lived excited state) as a mediator between the Rydberg excited state and the ground state. Atoms are first transferred from the Rydberg state to this intermediary state, which does not emit photons, and then detected via fluorescence imaging. This mediator state allows detection of the original Rydberg excitations without losing the atoms, resolving the contradiction between measurement precision and atom loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If destructive readout is used to obtain atom states, then computation results can be read, but the quantum processor must restart from scratch, reducing repetition rate

Engineering Contradiction:
Improvecomputation result retrievalVSAvoidpreparation time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent applies the principle of discarding and recovering by transferring atoms from the Rydberg excited state to a long-lived intermediary state that preserves the quantum information while allowing detection. Instead of discarding the atoms through destructive readout, the system recovers them in a detectable state, enabling repeated computation cycles without full re-preparation and thus reducing time loss.

Inventive Principle:
Principle #34Discarding and recovering

3Measurement precision

If fluorescence imaging is used after destructive readout, then empty sites can be identified, but atoms are lost and computation cycle time increases

Engineering Contradiction:
Improveempty site identificationVSAvoidcomputation repetition rate
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by first transferring atoms to the long-lived intermediary state before performing fluorescence imaging. This preliminary transfer ensures that atoms remain in the trap during imaging, allowing empty sites to be identified without atom loss. The computation cycle can then repeat faster, improving productivity while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

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 enables the determination of the states of neutral atoms after quantum computation with reduced atom loss, allowing for faster repetition rates of quantum computation cycles and improved fidelity of the quantum states.

Implementation Method 1

addressing a first laser beam on the array of qubits so as to transfer neutral atoms in the fundamental state to the dark state

Methodology Applied
Scientific EffectOptical pumping: Laser

Implementation Method 2

addressing a second laser beam on the array of qubits so as to transfer neutral atoms in the excited state to the fundamental state

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 3

collecting, by a detector, photons emitted by the neutral atoms passing from the intermediate state to the fundamental state by spontaneous emission

Methodology Applied
Scientific EffectSpontaneous emission: Light

Implementation Method 4

collecting, by a detector, photons emitted by the neutral atoms passing from the intermediate state to the fundamental state by spontaneous emission

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP4564239A1A method for imaging neutral atoms forming an array of qubits
Publication Date: 2025.06.04 PASQAL SAS
  • EP4564239A1 patent drawingFigure 1
  • EP4564239A1 patent drawingFigure 2
  • EP4564239A1 patent drawingFigure 3

AI summary

The invention relates to a method for imaging neutral atoms forming an array of qubits, the neutral atoms having a plurality of energy states comprising: a dark state, a fundamental state, an intermediate state and an excited state, the method comprising: - addressing a first laser beam on the array of qubits so as to transfer neutral atoms in the fundamental state to the dark state, - addressing a second laser beam on the array of qubits so as to transfer neutral atoms in the excited state to the fundamental state, - imaging the array of qubits, the generated image(s) enabling to obtain a state for each neutral atom of the array of qubits at the end of a quantum computation comprising at least an analog quantum computation operation.