Effect of ancilla's structure on quantum error correction using the 7-qubit Calderbank-Shor-Steane code

摘要

In this work we discuss the ability of different types of ancillas to controlthe decoherence of a qubit interacting with an environment. The error isintroduced into the numerical simulation via a depolarizing isotropic channel.After the correction we calculate the fidelity as a quality criterion for thequbit recovered. We observe that a recovery method with a three-qubit ancillaprovides reasonable good results bearing in mind its economy. If we want to gofurther, we have to use fault-tolerant ancillas with a high degree ofparallelism, even if this condition implies introducing new ancillaverification qubits.