ABSTRACT
Silicon has raised an increasing interest in the development of future devices for quantum information processing. Quantum computing consists of the implementation of quantum algorithms on a physical substrate made of interacting qubits, the quantum version of digital bits. Quantum algorithms are those algorithms conceived to solve hard computational problems, such as prime factorization of large integers and minimization of multidimensional functionals based on the encoding of the information by quantum states. In the simplest version, the quantum states arise from two-level systems and they provide the basis of the physical qubits. Such a physical basis is provided by quantum objects, like individual particles or superconducting currents, enabling the existence of a ground and an excited state, which can live simultaneously in a quantum superposition weighted by complex numbers. The possibility to encode the information in a superposition of states and to exponentially increase the number of possible states by using many qubits leads to the intrinsic parallelism that can be exploited by quantum algorithms (DiVincenzo 1995).
