Ladder Elements Mediate Qubit Coupling to Maintain Global Gap
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Solution Overview
Problem
In ferromagnetically coupled chains of qubits, the global gap collapses rapidly during quantum annealing, leading to increased decoherence and reduced sensitivity to flux noise, which degrades the performance of quantum processors.
Innovation Solution
The use of ladder elements that mediate interactions between qubits, allowing for longer ferromagnetic chains without compromising the qubit gap, by operating at a higher energy scale than the qubits and reducing the effect on tunneling dynamics, and enabling connections between qubits that do not have direct on-chip coupling through auxiliary qubits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ferromagnetically coupled chains of qubits are used to increase connectivity, then the ability to mediate long range interactions is improved, but the global gap collapses rapidly during quantum annealing
Solution Approach 1:
The patent introduces ladder elements as intermediary components that mediate interactions between qubits. These ladder elements operate at a higher energy scale and allow ferromagnetic coupling over longer distances without directly coupling qubits, thus maintaining the global gap while enabling long-range interactions and increased connectivity.
2Length of stationary object
If longer ferromagnetic chains are used to extend qubit connectivity, then the range of interaction is improved, but decoherence increases and sensitivity to flux noise decreases
Solution Approach 1:
Ladder elements serve as mediators that enable long-range ferromagnetic coupling without requiring direct long chains of coupled qubits. By operating at a higher energy scale, they extend the effective interaction range while isolating the qubits from decoherence and flux noise that would otherwise accumulate over longer chain lengths.
3Force
If direct on-chip coupling between qubits is implemented, then interaction strength is improved, but connectivity between non-adjacent qubits is limited
Solution Approach 1:
The ladder elements act as auxiliary mediators that enable indirect coupling between non-adjacent qubits. They provide a pathway for quantum interactions to propagate across the chip without requiring direct physical proximity, thus extending connectivity while maintaining effective interaction strength through the mediated coupling mechanism.
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 maintains the qubit gap and reduces decoherence, allowing for more robust and sensitive quantum processing by delaying the suppression of the global gap and enabling longer ferromagnetic chains without degrading the qubit performance.
Implementation Method 1
reducing the effect on tunneling dynamics
Implementation Method 2
ferromagnetically coupled chains of qubits
Implementation Method 3
Superconducting qubits are a type of superconducting quantum device
Implementation Method 4
compound Josephson junction
Data Source
AI summary
A ladder structure is ferromagnetically coupled to a first qubit where the ladder structure has a monostable energy potential in use, such that the first qubit and the ladder structure effectively operate as a single qubit. The ladder structure and first qubit may be coupled via a superconducting flux coupler. The ladder structure may be a chain of at least two ferromagnetically coupled ladder elements. A value for each ladder element may be less than about 1.