Silicon Quantum Dot Processing Element for High Fidelity Qubits
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Solution Overview
Problem
Current silicon-based quantum processors face challenges in achieving viable quantum dots due to high disorder environments and limited coherence times, particularly with the Si/SiO2 interface, which is not conducive to forming qubits with high fidelity and long dephasing times.
Innovation Solution
A processing element is developed using a silicon and silicon dioxide interface with isotopically enriched silicon to form quantum dots, where a control arrangement tunes the quantum properties, such as electron or hole spin, enabling high control fidelity and long coherence times, allowing for the formation of tuneable qubits that can be addressed individually or in groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum dots are formed using electrostatic gates on a GaAs/AlGaAs heterostructure, then quantum computation can be implemented, but coherence time is limited and fidelity is reduced due to nuclear spins in the crystal lattice
Solution Approach 1:
The patent changes the material parameter by replacing GaAs/AlGaAs heterostructure with silicon-based materials, specifically utilizing the silicon crystal lattice which has negligible nuclear spin, thereby extending coherence time and improving quantum state fidelity
Solution Approach 2:
The patent employs composite material structure combining silicon quantum dots with silicon dioxide (SiO2) interface, creating a hybrid system that leverages the advantageous properties of both materials - silicon for long coherence time and SiO2 for effective quantum dot confinement
2Ease of manufacture
If the Si/SiO2 interface is used to form quantum dots, then manufacturing can leverage existing CMOS technology, but the interface provides a high disorder environment that was previously considered not conducive to viable quantum dots
Solution Approach 1:
The patent converts the previously harmful high disorder environment at the Si/SiO2 interface into a beneficial configuration by precisely engineering the interface properties and using isotopically enriched silicon, transforming what was considered a defect into a manufacturable platform with long coherence times
Solution Approach 2:
The patent applies local quality enhancement by using isotopically enriched silicon-28 specifically at the quantum dot formation region, creating a localized area with extremely low nuclear spin concentration while maintaining compatibility with standard SiO2 dielectric layers
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 creation of highly tuneable quantum dots with extended coherence times, facilitating large-scale voltage-addressable qubit systems and leveraging existing MOSFET fabrication technologies, thereby improving the scalability and fidelity of quantum processing.
Implementation Method 1
a confining arrangement for confining one or more electrons or holes in the silicon to form a quantum dot
Implementation Method 2
the quantum property comprises electron or hole spin. The control is arranged to apply a voltage to tune the electron or hole spin resonance frequency
Implementation Method 3
the surface silicon layer in which the quantum dots are formed is isotopically enriched to contain predominantly 28Si atoms, and this embodiment therefore takes advantage of the long coherence times that become available due to the low nuclear spin concentration in the silicon lattice
Data Source
AI summary
A processing element for an advanced processing apparatus. The processing element comprises a silicon-insulator interface and a confining arrangement for confining one or more quantum dots in the semiconductor. The processing element has also a control arrangement for controlling a quantum property of the one or more quantum dots and operate the one or more quantum dots as a qubit to perform quantum processing.