Practical implementation of arbitrary nonlocal controlled-unitary gate via indefinite causal order

• URL: http://arxiv.org/abs/2603.08073v1
• Date: Mon, 09 Mar 2026 08:13:11 GMT
• Title: Practical implementation of arbitrary nonlocal controlled-unitary gate via indefinite causal order
• Abstract summary: Quantum gate teleportation enables the implementation of nonlocal quantum operations without direct interactions between distant nodes.<n>We propose an efficient protocol for implementing arbitrary controlled-unitary (CU) gates acting on two spatially separated parties via indefinite causal order (ICO)<n>Our work establishes a practical framework for scalable distributed quantum computation with flexible operations.
• Score: 5.3846617073090846
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Quantum gate teleportation enables the implementation of nonlocal quantum operations without direct interactions between distant nodes. We propose an efficient protocol for implementing arbitrary controlled-unitary (CU) gates acting on two spatially separated parties via indefinite causal order (ICO). By establishing a maximally entanglement between two remote nodes and coherently superposing orders of single-qubit gates, our protocol circumvents the drawback of complex local two-qubit operations. This ICO-based approach enables full programmability of CU gates by adjusting the inherent single-qubit operations, offering advantages over conventional fixed causal-order methods in terms of reduced circuit complexity and improved experimental flexibility. Furthermore, we develop an optical construction to implement the polarization CU gate using a stable and reciprocal Sagnac interferometer. Our work establishes a practical framework for scalable distributed quantum computation with flexible operations.

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