Curator's Take
This article tackles one of the most pressing challenges in scaling quantum computing: how to efficiently route quantum circuits across distributed systems where quantum cores are connected by limited entanglement resources. The proposed dSABRE algorithm represents a significant advance over existing methods by reducing consumption of precious Einstein-Podolsky-Rosen (EPR) pairs by 41-44% compared to current state-of-the-art approaches, essentially making distributed quantum computers far more resource-efficient. What makes this particularly exciting is that it addresses the fundamental bottleneck of inter-core communication in multi-core quantum processors, which will be crucial as we move toward larger, more practical quantum systems that can't fit all qubits on a single chip. The algorithm's demonstrated scalability up to 360 qubits suggests it could be instrumental in enabling the distributed quantum computing architectures that many believe will be necessary for achieving quantum advantage in real-world applications.
— Mark Eatherly
Summary
Minimising EPR consumption is the dominant objective when routing a quantum circuit on a distributed quantum computer (DQC). We present dSABRE, a SABRE-style router for multi-core processors that, on each iteration of a lookahead-driven loop, first resolves any intra-core front-layer gates by SWAP scoring and only falls back to scoring inter-core teleportation candidates when the intra-core front is empty. Three mechanisms drive the improvement over the state of the art: a five-term gate-centric teleportation score that generalises the local SWAP heuristic to the inter-core setting, whose explicit capacity-penalty term keeps the scorer from teleporting into saturated cores; a proactive congestion-relief pass that redistributes idle qubits out of high-demand cores before deadlock; and a BFS-layer construction of the inter-core extended set that respects DAG dependencies layer by layer rather than mixing wires in topological order. Across 18 MQT-Bench circuits at 25, 36, and 64 logical qubits, dSABRE reduces geometric-mean EPR consumption by 41-44% over TeleSABRE and by 16-68% over the gate-teleportation-based pytket-dqc, using standard Qiskit SabreLayout for the initial layout. A large-circuit QFT sweep at 100-360 qubits confirms scalability. Code and online appendices are available at https://github.com/ebony72/dsabre.