Extended Abstract Classical programmability is enough for quantum circuits universality in approximate sense It was shown by M. A. Nielsen and I. L Chuang [1], that it is impossible to build strictly universal programmable quantum gate array, that could perform any unitary operation precisely and it was suggested to use prob-abilistic gate arrays instead. In present work is shown, that if to us...

We demonstrate the operation of a two-bit "controlled-NOT" quantum logic gate, which, in conjunction with simple single-bit operations, forms a universal quantum logic gate for quantum computation. The two quantum bits are stored in the internal and external degrees of freedom of a single trapped atom, which is first laser cooled to the zero-point energy. Decoherence effects are identified for ...

Implementing a unitary operation using a universal gate set is a fundamental problem in quantum computing. The problem naturally arises when we want to implement some quantum algorithm on a fault tolerant quantum computer. Most fault tolerant protocols allow one to implement only Clifford circuits (those generated by CNOT, Hadamard and Phase gates). To achieve universal quantum computation one ...

Two possible quantum descriptions of the classical Not gate are investigated in the framework of the Hilbert space C: the unitary and the anti–unitary operator realizations. The two cases are distinguished interpreting the unitary Not as a quantum realization of the classical gate which on a fixed orthogonal pair of unit vectors, realizing once for all the classical bits 0 and 1, produces the r...

In the field of virtual reality, Collision Detection Technology was widely developed for improving the performance of 3D Graphics. Following rapid growth of virtual objects with complex shapes, conventional methods perform harder to effectively detect the collision. Facing the problem, we presented a collision detection algorithm based on improved quantum particle swarm optimization. Firstly, w...

Submitted for the MAR06 Meeting of The American Physical Society Optimizing quantum gate fidelities using energy-optimal control1 SONIA SCHIRMER, Univ. of Cambridge — Optimal control theory offers a promising framework for optimizing essential tasks in quantum computing from quantum state preparation to the implementation of quantum gates. It is applicable to a wide variety of systems from atom...

A conditional geometric phase shift gate, which is fault tolerant to certain types of errors due to its geometric nature, was realized recently via nuclear magnetic resonance (NMR) under adiabatic conditions. However, in quantum computation, everything must be completed within the decoherence time. The adiabatic condition makes any fast conditional Berry phase (cyclic adiabatic geometric phase)...

This paper provides the initial threshold to building of more complex system having reversible sequential circuits as a primitive component and which can execute more complicated operations using quantum computers. The reversible circuits form the basic building block of quantum computers as all quantum operations are reversible. The important reversible gates used for reversible logic synthesi...

We offer an alternative to the conventional network formulation of quantum computing. We advance the analog approach to quantum logic gate/circuit construction. As an illustration, we consider the spatially extended NOT gate as the first step in the development of this approach. We derive an explicit form of the interaction Hamiltonian corresponding to this gate and analyze its properties. We a...

We propose and demonstrate a new field-induced quantum dot transistor that has a nanoscale dot-gate inside the gap of a split gate. Because of the novel structure and small dot size, strong oscillations in the drain current as a function of the gate bias were observed at a temperature up to 4.2 K or with a drain bias up to 5 mV. Temperature dependent study showed that the energy gaps in the dot...