Optical QPU Multiplexing for Higher-Probability Resource States

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Solution Overview

Problem

Existing quantum computing systems face challenges in increasing the probability of generating desired quantum states, particularly non-Gaussian states, which are crucial for fault-tolerant quantum computation.

Innovation Solution

The implementation of optical multiplexers at the input to quantum processing units (QPUs) to selectively route optical signals based on signal quality metrics, such as homodyne and photon-number resolving measurements, to enhance the likelihood of generating high-quality resource states like GKP states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optical multiplexers are implemented to selectively route optical signals based on signal quality metrics, then the probability of generating desired resource states increases, but the device complexity increases

Engineering Contradiction:
Improveprobability of generating desired resource statesVSAvoidcomplexity of optical multiplexer system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary quality assessment of optical signals using homodyne and photon-number resolving measurements before routing them through multiplexers. This preliminary action allows the system to identify and select high-quality resource states in advance, increasing the probability of successful quantum computation while managing complexity through structured pre-processing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Optical multiplexers serve as intermediary components that mediate between the optical signal source and the quantum processing unit. These multiplexers selectively route signals based on quality metrics, acting as a buffer that improves reliability by filtering out low-quality states while maintaining manageable system complexity through modular architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple measurement techniques (homodyne and photon-number resolving) are used to assess signal quality, then the manufacturing precision of quantum states improves, but the measurement and detection difficulty increases

Engineering Contradiction:
Improveprecision of quantum state generationVSAvoiddifficulty of signal quality measurement
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The measurement process is segmented into two distinct techniques: homodyne measurement for assessing certain quantum state properties and photon-number resolving measurement for evaluating other critical attributes. This segmentation allows each measurement type to be optimized for its specific function, improving overall manufacturing precision while managing detection difficulty through specialized, modular measurement approaches

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes measurement parameters by switching between different measurement bases and techniques depending on the specific quantum state properties being assessed. This allows flexible adaptation to different measurement requirements, achieving high precision through parameter optimization while managing complexity through conditional measurement strategies

Inventive Principle:
Principle #35Parameter changes

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 approach increases the probability of generating desired resource states, enhancing the fault tolerance and computational efficiency of quantum computers by ensuring higher-quality optical signals are used for quantum computation.

Implementation Method 1

The at least one signal quality metric for each first optical signal can be determined based on a homodyne measurement of a previously entangled mode that was previously entangled with a first mode of that first optical signal

Methodology Applied
Scientific EffectHomodyne measurement: Homodyne Detection

Implementation Method 2

The signal quality metric for each first optical signal can be determined based on a photon-number resolving measurement of a previously entangled mode that was previously entangled with a first mode of that first optical signal

Methodology Applied
Scientific EffectPhoton-number resolving measurement: Photoelectric Effect

Implementation Method 3

Quantum computing is a type of computation whose operations can leverage quantum mechanical effects, such as superposition, interference, and entanglement

Methodology Applied
Scientific EffectQuantum entanglement:

Data Source

PatentEP4657332A1QPU multiplexing
Publication Date: 2025.12.03 XANADU QUANTUM TECHNOLOGIES HOLDINGS ULC
  • EP4657332A1 patent drawingFigure 1
  • EP4657332A1 patent drawingFigure 2A~2B
  • EP4657332A1 patent drawingFigure 2C

AI summary

A method for routing optical signals in a quantum computing system. A plurality of optical signals can be routed to one or more quantum processing units. A plurality of multiplexers are arranged at the input to each quantum processing unit. The multiplexers can be controlled to route optical signals with desired signal characteristics for quantum computation using the quantum processing unit. This can increase the likelihood of preferred resource states (e.g., non-Gaussian states) being available for quantum computation.