The quantum computer condition: requirements for viable computation

In this paper we review the content of the Quantum Computer Condition, which is a rigorously specified criterion that provides a set of mathematical constraints that must be satisfied by a physical system if we intend to use that system as a quantum computing machine, and we discuss an important consequence of it known as the Quantum Computing No-Go Theorem, which establishes a bound for decoherence and dissipation beyond which quantum computation is not possible. In connection with this theorem, we explicitly calculate a universal critical damping value for fault-tolerant quantum computation. We also discuss a relevant class of time-dependent generalizations of the Lindblad equation.