Magnetic Flux Source System for Quantum Energy State Control

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Solution Overview

Problem

Existing superconducting circuit systems face challenges in efficiently setting and maintaining discrete energy states in tunable current elements, which are crucial for magnetic flux biasing in quantum computing and sensing applications, due to limitations in controlling energy barriers and potential energy changes.

Innovation Solution

A magnetic flux source system utilizing tunable current elements with SQUIDs and inductors, where control currents are applied to induce bias and control fluxes to decrease energy barriers, change potential energy, and set specific energy states, allowing for stable operation and efficient flux biasing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If control currents are applied to induce bias flux in SQUID to decrease energy barriers, then the ability to set discrete energy states is improved, but the complexity of control circuitry increases

Engineering Contradiction:
Improveability to set discrete energy statesVSAvoidcomplexity of control circuitry
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple control functions into a single integrated control line that can induce both bias flux and control flux by applying different current amplitudes. This merging of functions reduces the number of separate control circuits needed while maintaining the ability to independently adjust energy barriers and set discrete energy states of the tunable current element

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control line is designed to perform multiple functions: it can induce bias flux to decrease energy barriers and simultaneously induce control flux to change potential energy and set discrete energy states. This multi-functionality reduces circuit complexity while achieving the desired control over the tunable current element

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If control currents are applied to induce control flux to change potential energy, then the precision of energy state setting is improved, but the energy consumption increases

Engineering Contradiction:
Improveprecision of energy state settingVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic or pulsed control currents rather than continuous currents to induce control flux. By applying currents only when needed to transition between energy states and then deactivating them, the system achieves precise energy state setting while minimizing continuous energy consumption. The control currents are activated temporarily to change potential energy and then deactivated to maintain the set state

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system changes the amplitude parameter of control currents to achieve different effects: higher amplitudes are used temporarily to induce sufficient control flux for precise energy state setting, while lower or zero amplitudes are used during maintenance phases. This dynamic parameter adjustment allows precise control while reducing overall energy consumption

Inventive Principle:
Principle #35Parameter changes

3Speed

If bias flux is induced to decrease relative energy barriers, then the speed of state transitions is improved, but the stability of maintained energy states deteriorates

Engineering Contradiction:
Improvespeed of state transitionsVSAvoidstability of energy states
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent applies bias flux temporarily as a preliminary action to decrease energy barriers and enable fast state transitions. Once the transition is complete, the bias flux is deactivated to restore the original energy barrier heights, thereby maintaining the stability of the final energy state. This preliminary action approach allows fast transitions without compromising long-term stability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bias flux is applied periodically or in pulses only during state transition events rather than continuously. This periodic application provides the necessary energy barrier reduction for fast transitions when needed, while allowing energy barriers to be restored for stability during maintenance phases, thus resolving the contradiction between transition speed and state stability

Inventive Principle:
Principle #19Periodic action

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

Enables precise control over energy states in tunable current elements, improving the stability and efficiency of magnetic flux biasing, thereby enhancing the performance of quantum computing and sensing applications.

Implementation Method 1

a first control line inductively coupled to a SQUID associated with the tunable current element and configured to conduct a first control current that induces a bias flux in the SQUID

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a second control line inductively coupled to an inductor provided in a series loop with the SQUID associated with the tunable current element, such that the second control current induces a control flux in the series loop

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

Each of the plurality of tunable current elements includes a SQUID that is inductively coupled to a respective one of at least one first control line

Methodology Applied
Scientific EffectSuperconducting quantum interference: Josephson Effect

Data Source

PatentEP3815146B1Magnetic FLUX source system
Publication Date: 2025.01.01 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3815146B1 patent drawingFigure 1~2
  • EP3815146B1 patent drawingFigure 3
  • EP3815146B1 patent drawingFigure 4

AI summary

One example includes a magnetic flux source system that includes a tunable current element (50). The tunable current element includes a SQUID (52) inductively coupled to a first control line (54) that conducts a first control current that induces a bias flux in the SQUID to decrease relative energy barriers between discrete energy states of the tunable current element. The system also includes an inductor (LI) in a series loop with the SQUID and inductively coupled to a second control (56) line that conducts a second control current that induces a control flux in the series loop to change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states to generate a current that provides a magnetic flux at an amplitude corresponding to the energy state of the at least one tunable current element.