Building blocks for quantum network architectures

Jiapeng Zhao, Stephane Vinet, Amir Minoofar +6 more

Abstract Current quantum networks are largely constrained to static, point-to-point links, which lack the scalability and resource efficiency required for distributed quantum computing, quantum sensing, and the emerging quantum internet. A critical barrier to progress is the absence of a switching technology capable of routing fragile quantum states without inducing decoherence or distinguishability. Here, we propose the Universal Quantum Switch architecture, a foundational building block allowing non-blocking, encoding-agnostic routing of quantum information, as well as seamless modality conversion between disparate quantum platforms. An integrated photonic prototype in thin-film lithium niobate is developed for polarization entanglement, allowing a reconfiguration rate up to 1 GHz. We experimentally demonstrate robust electro-optic switching of arbitrary entangled states at 1 MHz with an average fidelity of $96\%$ and a purity of 1, which satisfies the requirement of dynamic distributed quantum error correction between arbitrary quantum computing nodes, to the best of our knowledge, for the first time. Complementing these experimental results, we project the architecture's scalability, showing dimension-independent decoherence, and provide a scalable, interoperable building block for heterogeneous quantum network fabrics.

Martin Suchara, Joaquín Chung, Rajkumar Kettimuthu +3 more

Benoît Vermersch, Tomás Ramos, Philipp Hauke +1 more

In a ``chiral'' quantum network, the directionality of emission into photonic waveguides provides a new tool to realize quantum communication. Two different architectures with purely atomic waveguides are thoroughly investigated as possible building blocks for such networks, providing a path for implementations within state-of-the-art technology.

Jiapeng Zhao, Stéphane Vinet, Amir Minoofar +6 more

Quantum networks are a keystone of the quantum internet. However, existing implementations remain largely confined to static point-to-point links due to the absence of a switching paradigm capable of dynamically routing fragile quantum entanglement without introducing decoherence. Here, we propose the Universal Quantum Switch, a foundational building block allowing on-demand, non-blocking, and encoding-agnostic routing of quantum information, as well as seamless modality conversion between disparate quantum platforms. We develop a prototype in thin-film lithium niobate and experimentally demonstrate robust switching with $\le 4\%$ decoherence via thermo-optic modulation and high-speed electro-optic switching of arbitrary entangled states at 1 MHz. Moreover, we show that our platform can support reconfiguration speeds up to 1 GHz. To our knowledge, this work represents the first demonstration of multi-node dynamic entanglement distribution at these speeds. Complementing these experimental results, we project the architecture's scalability, showing dimension-independent decoherence, and provide a scalable, interoperable building block for heterogeneous quantum network fabrics.

Supriyo Banerjee, Biswajit Maiti, Banaini Saha