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Building a universal quantum computer is considered as one of the most challenging goals of modern physics by making real and at the same time questioning many fundamental aspects of quantum mechanics.

The biggest issue is that the quantum state of a qubit register can be controlled only up to a finite precision, due to either fluctuating experimental parameters or to the uncontrolled interaction with the environment. Remarkably, this does not forbid the implementation of a quantum computer because errors can be corrected to some extent by redundantly encoding the information into “logical” qubits that consist of several “physical” qubits. In the recent years the control accuracy of few qubit registers progresses in a variety of physical systems : trapped ions, superconducting circuits, spins, ... Several experiments have reported single-qubit-gate error rates below 0.1%, and two-qubit error rates below 1%, coming close to the “error rate threshold” of certain Quantum Error Correction (QEC) schemes. Experiments involving 10 to 50 qubits are planned for the near future.

In this context, many questions are pressing. On the experimental side: Are the experimental error rates really sufficient to implement QEC? What architecture can realistically reach the fault-tolerance level? On the theory side : Are there better QEC schemes less demanding in terms of physical qubits and gates overhead conceivable ? Are QEC schemes resilient to other error models than the simplistic ones? What is the “killer app” for a small-scale quantum computers with typically 50 physical qubits?

The goal of this workshop is to gather experts both on the theory and the experimental sides, and to address some of these issues.