Josephson-Coupled Resonator Amplifier for Wider Quantum Bandwidth
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Solution Overview
Problem
Non-degenerate Josephson amplifiers, such as the Josephson parametric amplifier, suffer from narrow bandwidth, small dynamic range, and complex auxiliary drive circuits, making them less suitable for scalable quantum architectures.
Innovation Solution
A Josephson-coupled resonator amplifier is developed, featuring first and second resonators with lumped-element capacitance and inductance, coupled by Josephson junctions to form a superconducting loop, allowing for a larger bandwidth and dynamic range, and a simpler drive circuit, using standard nanofabrication techniques and tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Josephson parametric amplifier (JPC) is used, then quantum-limited measurement capability is achieved, but bandwidth is limited to approximately 10 MHz
Solution Approach 1:
The amplifier is segmented into two distinct resonators (signal resonator and idler resonator) coupled by Josephson junctions, allowing independent optimization of each resonator's properties to achieve both quantum-limited performance and broader bandwidth operation
Solution Approach 2:
The invention transitions from a single-resonator system to a two-resonator coupled system, adding a dimensional aspect to the design space that enables simultaneous achievement of quantum-limited sensitivity and extended bandwidth through separate tuning of signal and idler frequency modes
2Measurement precision
If a Josephson parametric amplifier (JPC) is used, then quantum-limited measurement capability is achieved, but dynamic range is limited to a few photons
Solution Approach 1:
By segmenting the amplifier into two resonators with independent mode structures, the system can accommodate a broader range of photon numbers while maintaining quantum-limited performance, effectively increasing the dynamic range from a few photons to a larger operational range
Solution Approach 2:
The coupled resonator structure provides multi-functionality by enabling both quantum-limited single-photon detection and broader dynamic range operation, making the amplifier universally applicable across different quantum measurement scenarios
3Measurement precision
If a Josephson parametric amplifier (JPC) is used, then quantum-limited measurement capability is achieved, but auxiliary drive circuit complexity increases
Solution Approach 1:
The signal and idler resonators are merged into a single coupled system where the Josephson junctions provide both coupling and nonlinearity, eliminating the need for separate auxiliary drive circuits and reducing overall system complexity while maintaining quantum-limited performance
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
The Josephson-coupled resonator amplifier operates at the quantum limit with analog signals, offering improved bandwidth and dynamic range, and a more convenient topology, enabling scalable quantum architectures and sensitive quantum measurements.
Implementation Method 1
one or more Josephson junctions coupling the first resonator to the second resonator, whereby a superconducting loop is formed from at least the lumped-element inductance of the resonators and the one or more Josephson junctions
Data Source
AI summary
A Josephson-coupled resonator amplifier is provided. The Josephson-coupled resonator amplifier includes a first and a second resonator, each formed from respective lumped-element capacitance and respective lumped-element inductance. The Josephson-coupled resonator amplifier further includes one or more Josephson junctions coupling the first resonator to the second resonator, whereby a superconducting loop is formed from at least the lumped-element inductance of the resonators and the one or more Josephson junctions.