Josephson Loop Resonator Layout for Compact Quantum Oscillators
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Solution Overview
Problem
The distributed constant-type Josephson parametric oscillator is not suitable for integration in quantum computers due to its large area occupancy, making it challenging to integrate several thousands of nonlinear oscillators on a small chip.
Innovation Solution
A lumped constant-type Josephson parametric oscillator is designed using a loop circuit with a capacitor, where the loop circuit is shunted by the capacitor, reducing the area required and allowing for integration of multiple oscillators on a small chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a distributed constant-type resonator is used in a Josephson parametric oscillator, then the oscillator achieves stable operation at microwave frequencies, but the area occupied by the resonator becomes excessively large
Solution Approach 1:
The patent changes the fundamental parameter of resonator geometry from distributed constant-type (long wavelength-scale structure) to lumped constant-type (compact circuit elements). This parameter change transforms the resonator from a wavelength-scale transmission line structure into a compact LC circuit structure, reducing the area by several orders of magnitude while maintaining the resonant frequency through appropriate selection of inductance and capacitance values.
Solution Approach 2:
The patent segments the distributed resonator structure into discrete lumped elements (inductors and capacitors) that can be independently designed and positioned. This segmentation allows the resonator function to be achieved through compact circuit elements rather than a continuous distributed structure, enabling integration of multiple oscillators on a small chip.
2Area of stationary object
If the resonator length is reduced to decrease area occupancy, then integration of multiple oscillators becomes feasible, but achieving moderate nonlinearity and low loss becomes difficult
Solution Approach 1:
The patent uses parameter changes in the lumped inductance and capacitance values to achieve the desired resonant frequency, nonlinear coefficient, and quality factor in a compact structure. By carefully selecting the inductance of the loop circuit and the capacitance of the shunt capacitor, the oscillator achieves moderate nonlinearity and low loss without requiring a large physical area.
Solution Approach 2:
The patent introduces a shunt capacitor that can be dynamically controlled to adjust the resonant frequency and nonlinear characteristics of the oscillator. This dynamic control allows optimization of the nonlinear coefficient and loss characteristics while maintaining a compact area, enabling the oscillator to adapt to different operating conditions.
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 configuration reduces the area occupied by the circuit while attempting to achieve moderate nonlinearity and low loss, essential for quantum computers, though achieving the desired nonlinear coefficient and loss remains a challenge.
Implementation Method 1
a first Josephson junction, a second Josephson junction
Implementation Method 2
a first superconducting line, a second superconducting line
Data Source
AI summary
A resonator, an oscillator, and a quantum computer in which the area occupied by the circuit can be reduced is provided. A resonator (100) includes a loop circuit (110) in which a first superconducting line (101), a first Josephson junction (103), a second superconducting line (102), and a second Josephson junction (104) are connected in a ring shape, and a capacitor (120). The capacitor (120) and the loop circuit (110) are connected in a ring shape.