COSMOS

On the atomic scale, matter obeys the rules of quantum mechanics which are quite different from the classical rules that determine the properties of conventional computers. Today's advanced lithographic techniques can etch logic gates and wires less than a micron across onto the surfaces of silicon chips. Soon they will yield even smaller parts and inevitably reach a point where logic gates are so small that they are made out of only a handful of atoms. So, if computers are to become smaller in the future, new, quantum technology must replace or supplement what we have now. This article provides a grand overview of quantum information theory from the concept of quantum bits (qubits) to entanglement to quantum computation to quantum cryptography.

We present several physical applications that were generated in the framework of quantum information science. We emphasize the crucial role played, in this approach, by a group of unitary transformations, the generalized Pauli or Heisenberg–Weyl group, and by a non-classical property, called entanglement, which appears to be a basic ingredient in Quantum Information Theory. We sketch the links between entanglement and non-locality, and discuss an analogy between entanglement and (human) relationships.

Quantum teleportation is one of the most important manifestations of nonlocal nature. The basic theory and experiment are explained and reviewed for a qubit system and a continuous-variable system.

In this article, we will show how particle statistics can be used as a resource for quantum information processing. After introducing this fundamental aspect of quantum physics, we will present several examples showing how it is possible to perform both useful and efficient quantum information processing relying only on the effects of the indistinguishability of identical particles. All the proposed schemes can be implemented with current technology.

This article reviews quantum computing and quantum algorithms. Some insights into its potential in speeding up computations are covered, with emphasis on the use of Grover's Search. In the last section, we discuss applications of quantum algorithm to bioinformatics. In particular, the extension of quantum counting algorithm to protein mass spectra counting is proposed.

The purpose of this article is to review the literature for pure and mixed state geometric phase and also the experimental measurement of the phase using NMR.

The need for increased memory space and higher speed in computers has fueled the demand for smaller and faster computers. However, as the computer chips miniaturize, it becomes inevitable that we need to look at the possibility of manipulating and addressing atoms and molecules individually. One such possibility is a feasibility study of a quantum computer. In this report, we summarize some of the progress made in experimental realization of quantum computer in the last few years.