REU Project

Repeaters are key infrastructure in the building of long-range quantum networks, enabling long-distance entanglement between qubits. However, their performance may be limited by an asymmetric error model that is incompatible with their common symmetric error correction practices. This imbalance in the errors experienced by the control and the target motivates the use of distinct quantum codes in neighboring repeater stations. We desire a CX gate that has some notion of fault-tolerance, but all fully transversal gates between distinct code pairs have the code distance in the opposite configuration from the error distribution. We loosen the fault-tolerance constraint and show that even with partial transversality, logical CX with the desired asymmetrical protection is not constructable.