Gaussian Boson Sampling Layout for Heralded GKP State Preparation

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Solution Overview

Problem

Existing photonic quantum computing technologies face challenges in efficiently generating and manipulating non-Gaussian states, which are crucial for universal, fault-tolerant quantum computation, due to the probabilistic nature of Gaussian boson sampling devices and the need for additional components that introduce photon loss and complexity.

Innovation Solution

A GBS state preparation device using a set of N-1 beamsplitters and N-1 photon number resolving detectors to generate non-Gaussian states with a statistical probability greater than a predefined threshold, without requiring additional beamsplitters, by employing a network of beamsplitters and phase shifters to entangle modes and utilize PNR detectors for heralded state generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional beamsplitters are used to generate non-Gaussian states, then state generation capability is improved, but device complexity and photon loss increase

Engineering Contradiction:
Improvestate generation capabilityVSAvoidnumber of optical components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for additional beamsplitters by using a carefully designed network of N-1 beamsplitters and N-1 PNR detectors. The invention shows that with this specific configuration, non-Gaussian states can be generated without requiring extra optical components beyond what is already present in the Gaussian boson sampling device, thereby reducing device complexity while maintaining state generation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent demonstrates that the existing N-1 beamsplitters in the Gaussian boson sampling device can serve multiple functions: both for the primary GBS computation and for generating non-Gaussian states when combined with PNR detector measurements. This multi-functionality eliminates the need for separate dedicated components for state generation, reducing overall device complexity.

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

2Reliability

If additional optical components are added to manipulate quantum states, then state quality is improved, but photon loss increases

Engineering Contradiction:
Improvestate qualityVSAvoidphoton loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the need for additional optical components that would otherwise be required to generate non-Gaussian states. By using the existing N-1 beamsplitters in conjunction with PNR detector measurements, the invention achieves state generation without introducing extra components that would cause additional photon loss, thereby improving state quality while minimizing energy loss.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If probabilistic methods are used for state generation, then implementation simplicity is improved, but success probability is reduced

Engineering Contradiction:
Improveimplementation simplicityVSAvoidsuccess probability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs feedback through PNR detector measurements to conditionally generate non-Gaussian states. The measurement outcomes provide feedback that allows the system to selectively identify and herald successful state generation events, improving the effective success probability while maintaining the simplicity of the probabilistic implementation approach.

Inventive Principle:
Principle #23Feedback

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

The solution enables the probabilistic generation of high-quality non-Gaussian states, such as GKP states, with improved success probability and reduced photon loss, suitable for fault-tolerant quantum computing by minimizing the number of optical components and enhancing state quality through symmetric effective squeezing.

Implementation Method 1

causing interference of each mode from the set of N modes with two or fewer other modes from the remaining modes from the set of N modes, via an associated beamsplitter from a set of N-1 beamsplitters

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

generating a single-mode squeezed state of light in a first output mode using a first squeezed light source from a set of N squeezed light sources

Methodology Applied
Scientific EffectSqueezing:

Implementation Method 3

Each non-output mode from the set of N-1 non-output modes is measured using a photon number resolving (PNR) detector from a set of N-1 PNR detectors

Methodology Applied
Scientific EffectPhoton detection: Photoelectric Effect

Data Source

PatentEP4660897A1Apparatus and methods for gausssian boson sampling state preparation
Publication Date: 2025.12.10 XANADU QUANTUM TECHNOLOGIES HOLDINGS ULC
  • EP4660897A1 patent drawingFigure 1~2
  • EP4660897A1 patent drawingFigure 3
  • EP4660897A1 patent drawingFigure 4a~4b

AI summary

An apparatus includes a set of phase shifters, each phase shifter from the set of phase shifters optically coupled to one optical mode from a pair of optical modes configured to transmit substantially identical squeezed states of light. The apparatus also includes at least one directional coupler, each directional coupler from the at least one directional coupler optically coupled to a unique pair of phase shifters from the set of phase shifters. A photon number resolving (PNR) detector is operably coupled to a directional coupler from the at least one directional coupler. The apparatus is configured to generate, with a statistical probability greater than a predefined threshold, one or more desired non-Gaussian states of light, the one or more desired non-Gaussian states of light including at least one approximate Gottesman-Kitaev-Preskill (GKP) state.