Instruction-Set Architecture for Programmable NV-Center Quantum Repeater Nodes

2026-02-16

AI Summary

This work proposes the first instruction set architecture (ISA) tailored for nitrogen-vacancy (NV) center–based quantum repeaters, addressing the current lack of standardized programmable interfaces. The ISA leverages nuclear spin registers to control electron spin qubits and supports both deterministic and coherent programming paradigms. It enables a compact representation of the BBPSSW entanglement purification protocol through instruction vector encoding and integrates linear combinations of unitaries (LCU) with Kraus operator formalism to facilitate interference-based diagnostic capabilities such as fidelity witnessing. Experimental demonstrations highlight the novel utility of coherent register control in quantum calibration and diagnostics, establishing a foundation for scalable multi-spin quantum architectures.

Technology Category

• Machine Learning: Quantum Machine Learning
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Constraint Satisfaction and Optimization: Satisfiability

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work
• Search and Retrieval-Augmented AI: Web query analysis, representation and understanding

Abstract

Programmability is increasingly central in emerging quantum network software stacks, yet the node-internal controller-to-hardware interface for quantum repeater devices remains under-specified. We introduce the idea of an instruction-set architecture (ISA) for controller-driven programmability of nitrogen-vacancy (NV) center quantum repeater nodes. Each node consists of an optically interfaced electron spin acting as a data qubit and a long-lived nuclear-spin register acting as a control program. We formalize two modes of programmability: (i) deterministic register control, where the nuclear register is initialized in a basis state to select a specific operation on the data qubit; and (ii) coherent register control, where the register is prepared in superposition, enabling coherent combinations of operations beyond classical programmability. Network protocols are expressed as controller-issued instruction vectors, which we illustrate through a compact realization of the BBPSSW purification protocol. We further show that coherent register control enables interferometric diagnostics such as fidelity witnessing and calibration, providing tools unavailable in classical programmability. Finally, we discuss scalability to multi-electron and multi-nuclear spin architectures and connection to Linear combination of unitaries (LCU) and Kraus formulation.

Problem

• quantum repeater
• instruction-set architecture
• programmability
• NV-center
• quantum network

Innovation

• instruction-set architecture
• quantum repeater
• NV center
• coherent control
• programmable quantum node