Spin Qubit Isolation Regime for Stable Quantum Dot Charge States

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Solution Overview

Problem

Existing quantum computing methods using CMOS-compatible quantum dots face challenges with uncontrollable changes in charge states during qubit manipulation due to the Coulomb regime, which affects the stability and reliability of quantum operations.

Innovation Solution

A method is introduced where quantum dots are manipulated in a completely isolated regime, maintaining charge stability by configuring potential barriers to prevent charge transfer between target groups and other quantum dots, ensuring that charge states remain fixed during manipulation and conversion operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the Coulomb regime is used to fix the number of charge carriers in quantum dots, then charge stability is improved, but uncontrollable charge state changes occur during qubit manipulation

Engineering Contradiction:

Improvecharge state stabilityVSAvoidqubit manipulation reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The system is divided into target groups of quantum dots that are completely isolated from other quantum dots and reservoirs using potential barriers. This segmentation allows independent manipulation of each target group while maintaining charge stability through the isolating barriers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the isolation parameter from partial isolation (Coulomb regime) to complete isolation by configuring potential barriers that prevent charge carrier transitions entirely, not just energetically unfavorable ones. This parameter change eliminates unwanted charge state modifications during manipulation.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If potential barriers are configured to completely isolate target groups, then charge state retention is improved, but device complexity increases

Engineering Contradiction:

Improvecharge state retentionVSAvoidpotential barrier configuration complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The potential barriers serve multiple functions: they completely isolate target groups to retain charge states, define the boundaries of target groups, and enable controlled manipulation. This multi-functionality reduces the need for additional separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The potential barriers are dynamically configurable, allowing the system to switch between completely isolated regime for charge retention and other regimes for manipulation operations. This dynamic control enables flexible operation without permanent structural complexity.

Inventive Principle:

Principle #15Dynamics

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 ensures the retention of charge states during quantum dot manipulations, enhancing the stability and reliability of quantum computing operations by minimizing unwanted charge state modifications.

Implementation Method 1

each target group being defined by a potential barrier, the method comprising, for each target group: at least one total isolation step of the target group relative to the other quantum dots of the matrix, the potential barrier separating the target group of quantum dots of the matrix adjacent to the target group being configured in such a way that the charged particle or particles contained in the target group cannot cross the potential barrier

Methodology Applied

Scientific EffectPotential barrier: Potential Well

Implementation Method 2

The electrostatic potentials that make it possible to form the quantum dots and to control their potential are obtained from series of local gates

Methodology Applied

Scientific EffectElectrostatic potential: Electrostatics

Data Source

PatentUS12550627B2Method for determining the position of the completely isolated regime of a spin qubit and method for manipulating at least one spin qubit

Publication Date: 2026.02.10 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

A method for manipulating a group of quantum dots of a quantum dots matrix, called target group, each target group including a quantum dot and containing a charged particle, the matrix being connected to a reservoir of charged particles, each target group being defined by a potential barrier, each charged particle being a carrier of a charge and spin, the method including, for each target group, a total isolation procedure of the target group relative to the other quantum dots, the potential barrier separating the target group of quantum dots of the matrix adjacent to the target group being configured so that the charged particle(s) contained in the target group cannot cross the potential barrier in order to be moved to the adjacent quantum dots or to the reservoir even when such a transition is authorised from an energy standpoint; and maintaining the target group in the completely isolated regime.