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In this busy world, there is an estimation of 3.5 exabytes of information data been generated in a single day and the data is shared on more than 10 million computing devices. As We, human beings are wholeheartedly dependent on the digital based computing devices for knowledge sharing by means of text and image information for each and every commotion of the day. Now, the sustenance of life without computing is considered as perplexed. As per a report submitted by association of semiconductor industries which states that by 2040, it is not possible to provide power to computer machine which is available in good running conditions present throughout the globe. It's a known fact that the fundamental functionality of a computer system to modify and save the information data. Presently all the computer systems are using the classical technique to manipulate the data using single bits that stores the information data in form of 0's and 1's. [1To overcome the inability stated by semiconductor industry, the quantum physics has come up with a new concept which specifies that the quantum elements have the tendency to move in both directions i.e. fore and rear directions and its presence can be felt in both places at same time and travel itself instantly]1. This peculiar tendency of quantum particles had lead to quantum computing. The most critical property of quantum computing is its enhanced asset for characterization and construction of information data. A mechanism is developed to work on various operations for computation of information data. Qubits i.e quantum bits are used in Quantum computing, it consist of a third state excluding the traditional data states 0 and 1.Hence the time duration taken by quantum computing to modify the information data is much lesser than that of traditional computing. In this paper, we try to explore the concepts of quantum computing, how it is related to physics, how it can be used and implemented. [ABSTRACT FROM AUTHOR]

Ettore Majorana, in his short life, unintendedly has uncovered the most profound problem in quantum computation by his discovery of Majorana fermion, a particle which is its own anti-particle. Owing to its non-Abelian exchange statistics, Majorana fermions may act as a qubit for a universal quantum computer which is fault-tolerant. The existence of such particle is predicted in mid-gap states (zero modes) of a topological superconductor as bound states that have a highly entangled degenerate ground state. This introductory overview will focus on the simplest theoretical proposals of Majorana fermions for topological quantum computing in superconducting systems, emphasizing the quest from the scalability problem of quantum computer to its possible solution with topological quantum computer employing non-Abelian anyons on various platforms of certain Majorana fermion 'signature' encountered. [ABSTRACT FROM AUTHOR]

This paper reviews the history and current (2008) state-of-the-art methods for programming quantum computers. We analyze the needs for programming quantum computers in the near future (when actual quantum computing hardware is available), and use this analysis to predict the direction in which the field is moving, and make recommendations for further development of quantum programming language tools. [ABSTRACT FROM AUTHOR]

We present realistic simulation for single and double phosphorous donors in a silicon-based quantum computer design by solving a valley-orbit coupled effective-mass equation for describing phosphorous donors in strained silicon quantum well (QW). Using a generalized unrestricted Hartree-Fock method, we solve the two-electron effective-mass equation with quantum well confinement and realistic gate potentials. The effects of QW width, gate voltages, donor separation, and donor position shift on the lowest singlet and triplet energies and their charge distributions for a neighboring donor pair in the quantum computer(QC) architecture are analyzed. The gate tunability are defined and evaluated for a typical QC design. Estimates are obtained for the duration of spin half-swap gate operation. [ABSTRACT FROM AUTHOR]

We propose and find pulse sequences for non-adiabatic two-qubit gates (CNOT, swap and controlled Z gates) for the Kane silicon-based electron mediated nuclear spin quantum computer architecture. These quantum gates are simpler, with higher fidelity and faster than existing proposals. Any two qubit gate may be implemented using similar pulse sequences. In this paper, we investigate the effect of decoherence on the operation of these quantum gates and some simple algorithms for a variety of dephasing rates. Our model shows that conservative estimates of the dephasing rates in the Kane architecture give gate fidelities comparable to that required for fault tolerant quantum computing. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Markovian regime decoherence effects in quantum computers are studied in terms of the fidelity for the situation where the number of qubits N becomes large. A standard model involving three-state lambda system ionic qubits is considered, with qubits localised around well-separated positions via trapping potentials. The centre of mass vibrations of the qubits act as a reservoir. Coherent one and two qubit gating processes are controlled by time dependent localised classical EM fields that address specific qubits, the two qubit gating processes being facilitated by a cavity mode ancilla, which permits state interchange between qubits. With suitably chosen parameters, the decoherence time can be made essentially independent of N. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]