Superconducting Quantum Gate Coupling to Suppress ZZ Interaction
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Solution Overview
Problem
The existing quantum gate devices face challenges due to the extra ZZ interaction between superconducting circuits, which affects the energy states and resonance frequencies, leading to incorrect control of quantum bits and phase deviations.
Innovation Solution
The proposed quantum gate device incorporates a connection unit with a capacitor and superconducting wire to connect two superconducting circuits, along with a magnetic field application unit and a quantum gate control electromagnetic wave irradiation unit. Additionally, an unnecessary interaction suppression electromagnetic wave irradiation unit is used to irradiate a frequency between the first and second resonance frequencies, suppressing the ZZ interaction by 10 MHz or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two superconducting circuits are connected to form a quantum gate device, then quantum gate operation is enabled, but extra ZZ interaction occurs between the circuits causing energy state shifts and phase deviations
Solution Approach 1:
The patent introduces a capacitor as an intermediary element between the two superconducting circuits. This capacitor acts as a mediator that enables quantum gate operation while suppressing the harmful ZZ interaction. The capacitor's impedance characteristics allow it to block the direct coupling that causes ZZ interaction while still permitting the necessary quantum interactions for gate operations.
Solution Approach 2:
The patent modifies the impedance parameters of the connection between superconducting circuits by introducing a capacitor with specific impedance characteristics. By changing the electrical parameters (impedance, capacitance) of the connection, the system achieves both quantum gate functionality and suppression of ZZ interaction-induced energy state shifts.
2Device complexity
If superconducting circuits are directly connected for quantum gate operation, then circuit simplicity is maintained, but phase deviations occur due to ZZ interaction
Solution Approach 1:
The capacitor serves as a mediating component that introduces minimal additional complexity while significantly improving phase control accuracy. By placing this single intermediary element in the circuit connection, the system achieves precise phase control without requiring major structural redesigns or multiple complex components.
3Stability of the object's composition
If the resonance frequency is set based on individual circuit properties, then each circuit operates independently, but ZZ interaction causes energy state deviations when circuits are combined
Solution Approach 1:
The capacitor as an intermediary element decouples the energy interaction pathways that cause ZZ interaction, allowing each superconducting circuit to maintain its individual resonance stability while preventing the harmful coupling effects that would otherwise occur when the circuits are combined for quantum gate operations.
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 enables the suppression of the ZZ interaction's influence, allowing for accurate control of quantum gates and preventing phase deviations, thereby enhancing the operational reliability of the quantum gate device.
Implementation Method 1
In each of the first Josephson device 911 and the second Josephson devices 9121, 9122, . . . , a thin film made from an insulator is sandwiched between two superconductors.
Implementation Method 2
a superconducting wire, which is a wire made from a superconductor
Implementation Method 3
The first superconducting circuit 91 is a circuit equivalent to an LC resonance circuit including a coil and a capacitor.
Implementation Method 4
a first quantum gate control electromagnetic wave irradiation unit 95 which irradiates the first superconducting circuit 91 with an electromagnetic wave of a first predetermined frequency
Data Source
AI summary
A quantum gate device includes a first superconducting circuit which includes at least one of Josephson devices in an annular circuit including a superconducting wire and resonates at a first resonance frequency, a second superconducting circuit which includes at least one of Josephson devices in an annular circuit including a superconducting wire and resonates at a second resonance frequency, a connection unit which includes a capacitor and a superconducting wire provided at each electrode of the capacitor and connects the first and second circuits, a magnetic field application means applying a magnetic field to one or both of the first and second circuits, a quantum gate control electromagnetic wave irradiation unit irradiating one of the first and second circuits with a control electromagnetic wave, and an unnecessary transition suppression electromagnetic wave irradiation unit irradiating one of the first and second circuits with an unnecessary interaction suppression electromagnetic wave.