The implementation of quantum error-correction codes needs high efficiency transmission channels and significant physical resources. Here we show that aggregating quantum networks alleviate those issues when applied to the quantum Reed-Salomon code.
Advanced quantum networking systems rely on efficient quantum error correction codes for their optimal realization. The rate at which the encoded information is transmitted is a fundamental limit that affects the performance of such systems. Quantum aggregation allows one to increase the transmission rate by adding multiple paths connecting two distant users. Aggregating channels of different paths allows more users to simultaneously exchange the encoded information. Recent work has shown that quantum aggregation can also reduce the number of physical resources of an error correction code when it is combined with the quantum multiplexing technique. However, the difference in channel lengths across the various paths means some of the encoded quantum information will arrive earlier than others and it must be stored in quantum memories. The information stored will then deteriorate due to decoherence processes leading to detrimental effects for the fidelity of the final quantum state. Here, we explore the effects of a depolarization channel that occurs for the quantum Reed-Solomon code when quantum aggregation involving different channel lengths is used. We determine the best distribution of resources among the various channels connecting two remote users. Furthermore, we estimate the coherence time required to achieve a certain fidelity. Our results will have a significant impact on the ways physical resources are distributed across a quantum network.
Quantum communication technologies will play an important role in quantum information processing in the near future as we network devices together. However, their implementation is still a challenging task due to both loss and gate errors. Quantum error-correcting codes are one important technique to address this issue. In particular, the quantum Reed-Solomon codes well suited to communication tasks as photons can naturally carry more than one qubit of information. The high degree of physical resources required, however, makes such a code difficult to use in practice. A recent technique called quantum multiplexing has been shown to reduce resources by using multiple degrees of freedom of a photon. In this work, we propose a method to decompose multicontrolled gates using fewer controlled-x (CX) gates via this quantum multiplexing technique. We show that our method can significantly reduce the required number of CX gates needed in the encoding circuits for the quantum Reed-Solomon code. Our approach is also applicable to many other quantum error-correcting codes and quantum algorithms, including Grovers and quantum walks.