PhD transfer exam | Arnaud Carignan-Dugas, Investigating and Benchmarking Quantum Noise Channels

Nothing is perfect, especially not the implementation of a quantum computer. Fortunately, perfection is not a requirement, since we are satisfied with fault tolerant quantum computations (FTQCs), which allow arbitrary quantum computations with a reasonable overhead. However, FTQC is limited, as it can only be suitably performed in restricted regimes. Hence, it is crucial to conceive protocols meant to certify the validity of a given so-called fault tolerant quantum circuit. 

In this seminar, we will first unravel the behavior of quantum noise channels under composition. This entails an important application to the "interleaved randomized benchmarking" protocol. In second place, we will extend the "standard randomized benchmarking" protocol in order to cover sets of gates that are not constituting 2-designs. These first two sections will set the scene for our ultimate goal: benchmark efficiently (and independently of state preparation and measurement errors) any individual cyclic unitary operation.