An introduction to Fault-tolerant Quantum Computing

In this paper we provide a basic introduction of the core ideas and theories surrounding fault-tolerant quantum computation. These concepts underly the theoretical framework of large-scale quantum computation and communications and are the driving force for many recent experimental efforts to construct small to medium sized arrays of controllable quantum bits. We examine the basic principals of redundant quantum encoding, required to protect quantum bits from errors generated from both imprecise control and environmental interactions and then examine the principals of fault-tolerance from largely a classical framework. As quantum fault-tolerance essentially is avoiding the uncontrollable cascade of errors caused by the interaction of quantum-bits, these concepts can be directly mapped to quantum information.