Category:Few-Qubits Fault Tolerant Quantum Computing Network Stage

The fifth network stage differs from the earlier (Quantum Memory) stage by demanding that the local operations can be performed fault-tolerantly (without any error), which is considerably more challenging.The devices on the end nodes are not full fedged quantum computers but a smaller version of the same with fewer qubits than what is required to show quantum supremacy or efficiently do better than a classical computer. Fault tolerance implies that all error parameters of a quantum memory network can be made negligible by adding more resources. Here the number of qubits available is small enough such that the end nodes can be simulated effectively on a classical computer. Here, the main interest is the performance of the fault- tolerant scheme. However, this does not imply that the entire network can be simulated efficiently or that there would exist equivalent classical protocols; the effect of entanglement cannot generally be replicated classically.

Application

Having access to fault-tolerant gates allows higher-accuracy clock synchronization (3) and protocols that require many rounds of communication and high circuit depth to be useful. This includes distributed quantum computing as well as applications for full-scale quantum computing networks, restricted to few qubits. This could be of great practical interest, especially for applica- tions in the domain of distributed systems.

Relevant Parameters

• Number of logical qubits q