The Quantum Way of Doing Computations

Since the mid-1990s, we have seen how computers and many of their applications can be enhanced using quantum physics. This is timely since "Moore’s law", for the continuing development of conventional computers, will not apply to ever-smaller electronic components governed by quantum physics. All computations, in our heads or in computational devices, rely on the real physical processes of data input, data representation in a memory, data manipulation using algorithms and finally, data output. Building a quantum computer we then require quantum bits (qubits) as storage sites for quantum information, quantum registers and quantum gates for data handling and processing and the development of quantum algorithms. I will review the basic principles of quantum computation, and show how strings of trapped ions can be used to build a quantum information processor, and do basic computations. Routes towards a scalable quantum computer will be discussed.