Dual-Space Single-Species Ion Architecture for Quantum Computing

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Solution Overview

Problem

Dual-species trapped-ion quantum computing faces challenges such as inefficient sympathetic cooling, complex chain reordering, and lower fidelity for mixed-species two-qubit gates, which affect decoherence, calibration, and remote entanglement generation.

Innovation Solution

A dual-space, single-species architecture that utilizes two Hilbert spaces within a single ion species, allowing for reconfigurable ion chains, perfect mass-matching sympathetic cooling, and higher-fidelity gates without the need for narrow line cooling or mixed-species two-qubit gates, enabling mid-algorithm readout and remote entanglement generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dual-species trapped-ion architecture is used, then quantum information processing can be implemented, but sympathetic cooling efficiency decreases and chain reordering becomes complex

Engineering Contradiction:

Improvequantum information processing capabilityVSAvoidchain reordering complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs a single-species trapped-ion architecture where all ions in the chain are identical (e.g., all Yb+ ions), eliminating the need for complex chain reordering operations that would be required in dual-species systems. This homogeneous approach maintains quantum information processing capability while significantly simplifying the system architecture and operational complexity.

Inventive Principle:

Principle #33Homogeneity

2Adaptability or versatility

If mixed-species two-qubit gates are used, then remote entanglement generation is enabled, but gate fidelity decreases

Engineering Contradiction:

Improveremote entanglement generationVSAvoidgate fidelity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements two-qubit gates between identical ion species, which eliminates the fidelity penalties associated with mixed-species interactions. The homogeneous atomic structure ensures consistent coupling strengths and transition frequencies, enabling high-fidelity remote entanglement generation while maintaining the versatility of the quantum processor.

Inventive Principle:

Principle #33Homogeneity

3Temperature

If narrow line cooling is applied, then ion temperature can be reduced, but the system becomes more vulnerable to decoherence and calibration becomes slower

Engineering Contradiction:

Improveion temperatureVSAvoiddecoherence resistance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent utilizes the narrow natural linewidth of the Yb+ ion cooling transition (369.5 nm) to achieve ultra-cold temperatures without the drawbacks of other cooling schemes. By operating at this specific wavelength with precise laser control, the system reaches microkelvin temperatures while maintaining high coherence times and fast calibration speeds through optimized Raman transition parameters.

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If a single chain of ions is used, then the architecture is simplified, but reconfigurability is limited without physical shuttling

Engineering Contradiction:

Improvearchitecture simplicityVSAvoidion chain reconfigurability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic reconfigurability of the ion chain by utilizing controlled ion transport and shelving techniques. Ions can be moved to different positions in the trap or transferred to metastable states for temporary storage, enabling flexible quantum circuit implementation without requiring complex physical shuttling mechanisms. This dynamic control maintains architectural simplicity while providing full reconfigurability.

Inventive Principle:

Principle #15Dynamics

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 enhances the flexibility and efficiency of quantum information processing by reducing decoherence, improving calibration speed, and maintaining high fidelity for quantum operations, while simplifying chain reordering and cooling processes.

Implementation Method 1

applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold

Methodology Applied

Scientific EffectRaman transition:

Implementation Method 2

AC Stark shifts of the m-type (metastable qubit), including from the ion trap RF, needs to be considered/managed

Methodology Applied

Scientific EffectAC Stark shift:

Data Source

PatentUS20230140906A1Methods and apparatuses for raman addressing of disjointed transition sets in d-manifold

Publication Date: 2023.05.11 IONQ INC

AI summary

Aspects of the present disclosure may include a method and/or a system for applying, to one or more ions in an ion chain, a first light beam having a first polarization and a second light beam having a second polarization to transfer the one or more ions from a first state of a first manifold to a second state of the first manifold, applying, to the one or more ions, the first light beam and the second light beam to transfer the one or more ions from the second state back to the first state, and applying, to the one or more ions, a third light beam to transition the one or more ions from the first state to a third state in a second manifold.