Fortschritte der Physik
Quantum Simulators and Quantum Repeaters
Mladen Pavičić
Abstract
Two elements of quantum computation are considered: quantum computer logic and quantum repeater. It is shown that the quantum gate logic does have two different models and that it is therefore ambiguous. It is also shown that without additional conditions imposed on quantum gates one cannot arrive at a general quantum computer machine language. In absence of such conditions quantum entanglement remains a selection protocol which makes quantum computer equivalent to many photon intensity interferometry. As an example for such an entanglement we discuss a quantum optical repeater.