What if a quantum computer did not have to be built as one giant, delicate object? This experiment shows that separate quantum devices can be connected by a cable, unplugged, and still exchange information with about one percent loss.

Quantum devices are hard to make large because a single manufactured device is limited in both size and quality. A network of interchangeable modules could instead be assembled, reconfigured, and expanded like modern computers. But the crucial challenge is making the connections both interchangeable and accurate.

This work uses a detachable cable between superconducting quantum devices. The basic idea is like passing a fragile package between two rooms through a temporary conveyor belt: the package must cross quickly, because every extra moment creates another chance for damage.

Here, the target is an efficient swap gate between distant qubits, moving the quantum state from one device to the other. The plan is to make the exchange fast: cable coupling can harm the qubit, while slower operation allows decoherence to create inefficiency.

This picture explains a plug-and-play route to larger quantum machines: separate qubit modules can exchange quantum information through a detachable cable, while the proposed control scheme balances transfer speed against losses in the cable. The link combines separately packaged qubits with a reliably pluggable coaxial cable and fast, high-fidelity transitions.

It does not need extra circuit elements beyond the qubits' own behavior. That combination produces swaps between modules with about one percent loss in under one hundred nanoseconds, matching the performance of permanent superconducting bonds.

The central benchmark is an inefficiency of about one percent in a swap gate lasting less than one hundred nanoseconds. The loss stays about the same even when the gate is made faster. The transfer repeatedly moves an excitation between two separate qubits with about one percent loss per operation, while preserving its phase well enough to create entanglement between them.

That makes the link fast, reliable, and useful for joining otherwise separate quantum devices. The two qubits can be placed in a maximally entangled Bell state, a situation where their measurement results are linked even though the qubits are separate.

The estimated fidelity of that shared state is zero point nine eight, while the remaining limit comes from loss of the qubits' own stored state rather than loss in the cable. The connection can be attached again with reproducible performance. Its settings change strongly between assembly cycles, but fast transfers can still be achieved reliably.

The same drive scheme also enables high-fidelity entanglement and operation of a logical qubit distributed across the modules. The present connection is not yet perfect, because it can affect how long the qubits preserve information. A more mature design that preserves the best coherence times could reduce errors toward one part in a thousand.

At that level, operations between modules would stand on equal footing with operations inside one module, removing the need to treat the connection as a weak link. The key result is a detachable link that moves quantum information between separate devices quickly enough to match the demands of large-scale quantum computing.

That could make future machines easier to upgrade, repair, and expand.