Multispecies Trapped-Ion Node for Qubit Isolation and Networking

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Solution Overview

Problem

Trapped atomic ions in quantum information networks require extreme isolation between memory qubits and photonic interfaces to maintain coherence and prevent quantum memory destruction, which is challenging due to the disturbance caused by resonant photons during communication operations.

Innovation Solution

The use of co-trapped 171Yb+ and 138Ba+ qubits in a multispecies ion trap network, where 138Ba+ qubits are used for communication and 171Yb+ qubits for memory, leveraging their different electronic transition frequencies to achieve isolation and enable local and remote entanglement through Coulomb interactions and photonic channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If resonant photons are used for photonic interface operations, then communication functionality is improved, but quantum memory coherence is destroyed

Engineering Contradiction:
Improvecommunication functionalityVSAvoidquantum memory coherence
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system segments the quantum node into two distinct qubit species: communication qubits (for photonic interface operations) and memory qubits (for quantum information storage). This segmentation allows resonant photons to interact only with communication qubits while leaving memory qubits isolated and coherent, resolving the contradiction between communication functionality and memory coherence preservation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple qubit species are co-trapped, then isolation between memory and communication qubits is improved, but system complexity increases

Engineering Contradiction:
Improveisolation between qubit speciesVSAvoidmultispecies ion trap system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system exploits fundamental parameter differences between qubit species (different atomic masses, different electronic transition frequencies, different trapping frequencies) to achieve natural isolation. Memory qubits and communication qubits respond to different laser frequencies and have different motional characteristics, allowing selective addressing and interaction while maintaining coherence isolation, thus improving reliability without requiring additional complex isolation mechanisms.

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 maintains the coherence of 171Yb+ memory qubits by preventing resonant processes from affecting them, allowing for long-lived quantum information storage and efficient communication, with demonstrated coherence times exceeding minutes and fidelity in entanglement operations.

Implementation Method 1

long-lived identical qubit memories that can be locally entangled through their Coulomb interaction

Methodology Applied
Scientific EffectCoulomb interaction: Coulomb's Law

Implementation Method 2

remotely entangled through photonic channels

Methodology Applied
Scientific EffectPhotonic entanglement: Electromagnetic Induction

Implementation Method 3

leveraging their different electronic transition frequencies to achieve isolation

Methodology Applied
Scientific EffectElectronic transition frequency difference: Resonance

Data Source

PatentEP3707648B1Quantum network node and protocols with multiple qubit species
Publication Date: 2023.09.27 UNIV OF MARYLAND
  • EP3707648B1 patent drawingFigure 1
  • EP3707648B1 patent drawingFigure 2(a)~2(b)
  • EP3707648B1 patent drawingFigure 3

AI summary

The disclosure describes aspects of using multiple species in trapped-ion nodes for quantum networking. In an aspect, a quantum networking node is described that includes multiple memory qubits, each memory qubit being based on a 171Yb+ atomic ion, and one or more communication qubits, each communication qubit being based on a 138Ba+ atomic ion. The memory and communication qubits are part of a lattice in an atomic ion trap. In another aspect, a quantum computing system having a modular optical architecture is described that includes multiple quantum networking nodes, each quantum networking node including multiple memory qubits (e.g., based on a 171Yb+ atomic ion) and one or more communication qubits (e.g., based on a 138Ba+ atomic ion). The memory and communication qubits are part of a lattice in an atomic ion trap. The system further includes a photonic entangler coupled to each of the multiple quantum networking nodes.