Encoded Superconducting Qubit Control via DC Pulses

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Solution Overview

Problem

Conventional superconducting qubit control methods rely on microwave signals, which limit operation speed and design flexibility, and are not well-suited for superconductor-based quantum computers.

Innovation Solution

The implementation of an encoded qubit scheme that uses a pair of physical superconducting qubits with tunable frequencies, allowing for microwave-free control via fast DC-like pulses, thereby divorcing the qubit frequency from control electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If microwave control is used for superconducting qubits, then qubit operation can be achieved, but operation speed is limited and design flexibility is reduced

Engineering Contradiction:

Improveoperation speedVSAvoiddesign flexibility

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

The patent changes the control parameter from microwave frequency to DC voltage, enabling faster rise times and improved operation speed while simultaneously divorcing qubit frequency from control electronics, thereby increasing design flexibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the electromagnetic microwave control mechanism with a DC voltage control mechanism, eliminating the limitations of microwave-based control and enabling faster, more flexible qubit manipulation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If microwave control is used for superconducting qubits, then qubit states can be manipulated, but control electronics must be coupled to qubit frequency

Engineering Contradiction:

Improvecontrol operationVSAvoidcontrol electronics coupling

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the frequency coupling requirement from the control system by using DC voltage instead of microwave signals, simplifying the control electronics and decoupling them from qubit frequency requirements

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes microwave electromagnetic control with DC voltage control, eliminating the need for frequency-matched control electronics and simplifying the overall system architecture

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9996801B2Microwave-free control of a superconductor-based quantum computer

Publication Date: 2018.06.12 UNIV OF MARYLAND

AI summary

Physical superconducting qubits are controlled according to an “encoded” qubit scheme, where a pair of physical superconducting qubits constitute an encoded qubit that can be controlled without the use of a microwave signal. For example, a quantum computing system has at least one encoded qubit and a controller. Each encoded qubit has a pair of physical superconducting qubits capable of being selectively coupled together. Each physical qubit has a respective tunable frequency. The controller controls a state of each of the pair of physical qubits to perform a quantum computation without using microwave control signals. Rather, the controller uses DC-based voltage or flux pulses.