SQUID Oscillator Ground-Plane Bridge for Crosstalk Suppression
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Solution Overview
Problem
Superconducting quantum circuits face significant challenges in reducing crosstalk, particularly when high-frequency control signals are applied, leading to unintended resonance frequency changes in adjacent quantum bits, which affects the accuracy and stability of quantum operations.
Innovation Solution
The implementation of an oscillator design that includes a SQUID, transmission lines, a ground plane, and a connection circuit connecting parts of the ground plane across the transmission line, specifically positioned near the node of the electric field generated during oscillation, effectively reduces crosstalk by minimizing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a coplanar waveguide structure is used for manufacturing superconducting quantum circuits, then the quantum bits can be integrated on a chip, but crosstalk occurs between adjacent quantum bits due to electromagnetic coupling through the ground plane
Solution Approach 1:
The patent introduces a connection circuit as an intermediary element between adjacent quantum bits. This connection circuit is specifically positioned at the node of the electric field of a standing wave to provide a controlled electromagnetic path that prevents unwanted coupling between quantum bits, thereby reducing crosstalk while maintaining the coplanar waveguide structure for integration.
2Ease of operation
If control signals are applied to quantum bits, then quantum operations can be performed, but unintended resonance frequency changes occur in adjacent quantum bits due to crosstalk
Solution Approach 1:
The connection circuit serves as a mediator that isolates adjacent quantum bits during control signal application. By providing a controlled electromagnetic path at the standing wave node, it prevents control signals from unintentionally coupling with adjacent quantum bits, thereby maintaining resonance frequency stability during quantum operations.
Solution Approach 2:
The patent utilizes the parameter of electromagnetic field distribution by positioning the connection circuit at the node of the standing wave's electric field. This strategic positioning exploits the minimal field variation at the node to minimize coupling effects while allowing full control signal operation.
3Reliability
If ground planes are used for signal reference, then signal integrity is maintained, but electromagnetic coupling between adjacent quantum bits increases crosstalk
Solution Approach 1:
The connection circuit acts as an intermediary that modifies the ground plane's electromagnetic characteristics. It provides a controlled path that maintains the ground reference function while preventing unwanted electromagnetic coupling between adjacent quantum bits, thus preserving signal integrity without increasing crosstalk.
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 significantly reduces high-frequency crosstalk while maintaining the quality factor of the quantum bits, preventing deterioration and ensuring precise control over resonance frequencies.
Implementation Method 1
crosstalk means a phenomenon in which, for example, when a control signal is input to a given quantum bit, that control signal couples with another quantum bit for some reason
Implementation Method 2
a first connection circuit disposed in a vicinity of a node of an electric field of a standing wave that is generated when the oscillator is oscillating
Data Source
AI summary
An oscillator in which crosstalk can be reduced is provided. An oscillator includes a SQUID, a transmission line connected to the SQUID, a ground plane, and a first connection circuit disposed in a vicinity of a node of an electric field of a standing wave that is generated when the oscillator is oscillating, the first connection circuit connecting parts of the ground plane located on both sides of the transmission line to each other.