Inductive-Coupled Parametric Amplifiers for Wider Qubit Readout Bandwidth
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Solution Overview
Problem
Existing parametric amplifiers in quantum computing systems face limitations due to capacitive input coupling, which leads to unwanted resonances and a narrow bandwidth, restricting their applicability and performance in quantum computing applications.
Innovation Solution
The implementation of a Josephson parametric amplifier with a quarter-wave transmission-line resonator that inverts the input coupling reactance from capacitive to inductive, mitigating unwanted resonances and enhancing bandwidth and dynamic range by using a multi-pole matching network and a quarter-wave transmission-line resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If capacitive input coupling is used in parametric amplifiers, then the amplifier can be constructed with conventional coupling methods, but unwanted resonances occur and bandwidth is narrow
Solution Approach 1:
The patent inverts the conventional capacitive coupling approach by using inductive coupling through a transmission-line resonator. This inversion changes the coupling mechanism from capacitive (block diagram 300) to inductive (block diagram 500), thereby eliminating unwanted resonances and expanding bandwidth while maintaining manufacturability through standard inductive coupling techniques.
Solution Approach 2:
The patent changes the coupling parameter from capacitive reactance to inductive reactance by introducing a transmission-line resonator. This parameter change transforms the coupling characteristics, removing resonant interference and broadening the operational bandwidth of the parametric amplifier while preserving ease of construction.
2Device complexity
If capacitive input coupling is used in parametric amplifiers, then the amplifier structure remains simple, but bandwidth is limited and dynamic range is reduced
Solution Approach 1:
The patent inverts the coupling approach from capacitive to inductive, using a transmission-line resonator to provide inductive coupling. This inversion increases bandwidth and dynamic range without significantly increasing structural complexity, as the resonator can be integrated into existing amplifier architectures.
Solution Approach 2:
The transmission-line resonator acts as an intermediary element that provides inductive coupling between the input signal and the parametric amplifier. This intermediary structure enables broader bandwidth and enhanced dynamic range while maintaining a relatively simple overall amplifier design.
3Adaptability or versatility
If inductive coupling with transmission-line resonator is used, then bandwidth and dynamic range are enhanced, but the amplifier requires additional resonator components
Solution Approach 1:
The transmission-line resonator serves multiple functions: it provides inductive coupling, defines the input impedance, and sets the operational frequency. By combining these functions into a single component, the patent enhances bandwidth and dynamic range without proportionally increasing overall device complexity.
Solution Approach 2:
The transmission-line resonator acts as a multi-functional intermediary that simultaneously provides coupling, impedance matching, and frequency selection. This consolidates multiple requirements into one component, achieving enhanced performance with manageable complexity.
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 solution enables high-instantaneous bandwidth and high dynamic range, effectively amplifying qubit-read signals while reducing stray resonances, thus improving the reliability and performance of quantum computing systems.
Implementation Method 1
The first transmission-line resonator provides an inductive reactance for an electrical coupling between the first measurement device and the first amplifier. The inductive reactance for the electrical coupling enables a transmission of the first qubit signal.
Implementation Method 2
The implementation of a Josephson parametric amplifier with a quarter-wave transmission-line resonator that inverts the input coupling reactance from capacitive to inductive
Data Source
AI summary
The disclosure is towards parametric amplifiers with inductive input coupling for quantum computing systems. One example aspect of the present disclosure is directed to a quantum computing system comprising a first qubit, a first measurement device, and a first amplifier. The first measurement device is configured to generate a first qubit signal corresponding to a first quantum state of the first qubit. The first amplifier is configured to amplify the first qubit signal. The first amplifier comprises a first transmission-line resonator. The first transmission-line resonator provides an inductive reactance for an electrical coupling between the first measurement device and the first amplifier. The inductive reactance for the electrical coupling enables a transmission of the first qubit signal.