Spin-Triplet Josephson Junctions for Longer Qubit Coherence
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Solution Overview
Problem
Superconducting qubits in quantum information systems suffer from low coherence times due to high energy loss, limiting their ability to store quantum information effectively.
Innovation Solution
The use of spin-triplet superconductors (STS) in quantum information systems, specifically in Josephson junctions, to reduce energy loss and increase coherence times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional superconductors (aluminum or spin-singlet) are used in superconducting qubits, then the qubits can be manufactured with current technology, but the coherence time is short due to high energy loss through multiple channels including two level systems and unpaired spins on surface
Solution Approach 1:
The patent changes the fundamental parameter of superconducting electron pairing from spin-singlet (conventional) to spin-triplet state. This parameter change fundamentally alters the energy loss mechanisms by eliminating the dominant loss channels associated with unpaired spins and two-level systems, thereby extending coherence time
Solution Approach 2:
The patent employs a composite structure combining spin-triplet superconducting material with conventional superconducting components. The spin-triplet layer is integrated into the superconducting qubit architecture to specifically address energy loss pathways while maintaining the overall functionality of the quantum system
2Manufacturing precision
If the number of material defects is reduced through advances in manufacturing technology or decreasing the size of the circuit, then coherence times have been improved, but the fundamental energy loss mechanisms remain unchanged
Solution Approach 1:
Rather than continuing to optimize manufacturing precision to reduce defects, the patent fundamentally changes the superconducting pairing parameter to spin-triplet state. This addresses the root cause of energy loss rather than merely reducing the impact of material imperfections
3Loss of energy
If topological superconductivity is achieved, then energy loss should be completely solved, but a topological superconductor with the desired properties has yet to be discovered after over 20 years of research
Solution Approach 1:
The patent applies spin-triplet superconductivity locally within specific regions of the qubit structure rather than requiring a complete topological superconductor material. This localized approach achieves the beneficial energy loss reduction without requiring the discovery of elusive topological superconducting materials
Solution Approach 2:
The spin-triplet superconducting layer acts as an intermediary component that mediates between conventional superconducting materials and the quantum information processing functions. It provides the necessary protection against energy loss while working within existing material capabilities
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
Implementing STS in quantum information systems enhances coherence times of superconducting qubits, thereby improving the performance and stability of quantum information storage.
Implementation Method 1
The present invention use spin-triplet superconductors (STS). Electrons in a STS are spin-polarized, meaning that all the electron spins are, and want to stay, aligned parallel with one another.
Implementation Method 2
Current superconducting circuits typically employ aluminum or other spin-single superconductors that lose energy to the surrounding environment through multiple channels, including, among others, two level systems or unpaired spins on a surface.
Data Source
AI summary
An apparatus includes a first superconductor layer, an insulating layer, and a second superconductor layer, wherein the second superconductor layer is a spin triplet superconductor (STS) layer. In some embodiments, the first superconductor layer is also a STS layer. In some embodiments, the second superconductor layer includes UCoGe. In some embodiments, the insulating layer includes uranium oxide. In some embodiments, the uranium oxide is created by exposing the second superconductor layer to an oxidizing gas, with or without heating. In some embodiments, the first superconductor layer, the insulating layer and the second superconductor layer form a Josephson junction.