Stasistically constrained operator associated with additivity of communication channel

Additivity of quantum communication channel is discussed in terms of Poisson process to show it is additive in probability. Poisson process is shown to be responsible for entanglement which is a rare event.Comment: 6 pages, 2 figures, Quantum Optics and Application in Computation and Communication (Nov. 2004 Beijing

NMR Quantum Computer; Efficient Simulation of C^nNOT with Elementary Quantum Gates

On an (n+2)-bit quantum network, a gate for conditional NOT operation with n≧5 bits of controls (a C^nNOT gate) can be simulated with 24n-64 gate of conditional two-bit operations, as well as with 32n-4 gates of CNOT and one-bit operations. These small numbers of elementary gates (which are approximately half or two thirds of the number known so far) help toward implementation of the oracle U_f: |x>|y>→|x>|y+f(x)> on quantum computers

NMR Quantum Computer

The quantum computer is a potential computing machine which employs interacting quantum two level systems as quantum bits. We studied a problem simulating a C^nNOT gate by a combination of CNOT gates and 1-bit phase rotation gates. The results are that, of 8(n-3) C^2NOT gates, 8(n-5) gates can be simulated by two CNOT and two 1-bit gates, 8 gates by 3 CNOT and 4 1-bit gates, and residual 8 gates by 48 CNOT and 52 1-bit gates