Neutral Atom Trapping With Narrow-Line Cooling for Lower Laser Power

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Solution Overview

Problem

The growth of large-scale quantum computing using neutral atom platforms is limited by the increasing laser power requirements as the number of qubits increases, making it difficult to add more optical tweezers.

Innovation Solution

A method and system for trapping neutral atoms using a reference cooling step to achieve colder atoms by transitioning to a second excited state with a narrower linewidth, allowing for lower laser power trapping in an array of sites, and optionally including preliminary and further cooling steps to achieve even lower temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If more optical tweezers are added to increase the number of qubits, then the number of qubits increases, but the required laser power grows linearly and eventually becomes unavailable

Engineering Contradiction:
Improvenumber of qubitsVSAvoidlaser power
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent changes the cooling parameter from using the first excited state to using the second excited state with a narrower linewidth. This parameter change enables more efficient cooling to lower temperatures, which directly reduces the laser power required for trapping. The narrower linewidth of the second excited state transition allows for more selective and efficient cooling, breaking the linear relationship between qubit number and laser power requirement.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If atoms are cooled to lower temperatures to enable lower power trapping, then trapping power is reduced, but achieving colder temperatures requires more sophisticated cooling mechanisms

Engineering Contradiction:
Improveatom temperatureVSAvoidcooling mechanism complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent segments the cooling process into two distinct stages: first cooling atoms from the first excited state to an intermediate temperature, then cooling from the second excited state to the final lower temperature. This segmentation allows each cooling stage to be optimized independently, achieving lower final temperatures without proportionally increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses the second excited state as an intermediary cooling stage. By introducing this intermediate energy state with a narrower linewidth, the system can transfer atoms through a two-step cooling process rather than attempting direct cooling to the final temperature, thereby achieving lower temperatures with manageable complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the magneto-optical trap uses a transition with a narrower linewidth, then cooling efficiency is improved and atom temperature is reduced, but the trap configuration becomes more complex

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmagneto-optical trap configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary cooling using the first excited state before transitioning to cooling with the second excited state. This preliminary action prepares the atoms by reducing their initial temperature and population, making the subsequent cooling with the narrower linewidth transition more effective and reducing the overall complexity burden.

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 more efficient trapping of neutral atoms with reduced laser power, increasing the number of qubits without the limitations of traditional methods.

Implementation Method 1

cooling down the neutral atoms in at least a magneto-optical trap suitable for imparting a transition between the fundamental state and the second excited state

Methodology Applied
Scientific EffectLaser cooling: Cooling

Implementation Method 2

single atoms are trapped in an array of traps formed by optical tweezers

Methodology Applied
Scientific EffectOptical tweezers: Optical Tweezers

Data Source

PatentEP4648065A1A method for trapping neutral atoms, associated system and quantum computer
Publication Date: 2025.11.12 PASQAL SAS
  • EP4648065A1 patent drawingFigure 1
  • EP4648065A1 patent drawingFigure 2
  • EP4648065A1 patent drawingFigure 3

AI summary

The invention relates to a method for trapping neutral atoms in an array of trapping sites, the neutral atoms having: a fundamental state, a first excited state and a second excited state, the second excited state having a higher principal quantum number than the first excited state, the second excited state having the same hyperfine electronic structure than the first excited state, the method comprising: - a step of cooling down the neutral atoms in at least a magneto-optical trap suitable for imparting a transition between the fundamental state and the second excited state, so as to obtain neutral atoms which are colder than with a magneto-optical trap suitable for imparting a transition between the fundamental state and the first excited state, and - a step of trapping cooled down neutral atoms in an array of trapping sites.