Distributed Quantum Computing

Distributed quantum computing links several QPUs so that they function together as a single, larger machine. The motivation is that monolithic scaling runs into hard engineering ceilings: control wiring density, dilution refrigerator cooling power, crosstalk between neighbouring qubits, and fabrication yield all worsen as a single chip grows, so at some point adding modules becomes easier than adding qubits to one die. Operations that span nodes are implemented using shared entanglement rather than physical wires — a pre-distributed entangled pair plus classical communication lets you teleport a qubit's state between nodes, or apply a teleportation-based two-qubit gate across the boundary without ever moving the data qubit itself. The central constraint is the interconnect: generating remote entanglement is currently far slower and far lower in fidelity than an on-chip gate, often by several orders of magnitude, so the link rather than the processor becomes the bottleneck and every cross-node operation is expensive in both time and error budget. This remains an active research direction with small proof-of-principle demonstrations, not a deployed capability.