No abstract

No abstract

This paper studies the infinite-time and finite-time synchronization of coupled harmonic oscillators with distributed protocol in the scenarios with and without a leader. In the absence of a leader, the convergence conditions and the final trajectories that each harmonic oscillator follows are developed. In the presence of a leader, it is shown that all harmonic oscillators can achieve the trajectory of the leader in finite time. Numerical simulations of six coupled harmonic oscillators are given to show the effects of the interaction function parameter, algebraic connectivity and initial conditions on the convergence time.

No abstract

No abstract

We propose a new protocol for deterministic secure quantum communication with a four-qubit W state. In this protocol, by using four local two-particle unitary operations and Bell basis measurements, the two legitimate users can directly transmit secret messages after exchanging some additional classical information. It will be shown that our protocol has a high capacity as each W state can carry two bits of secret information, and has a high intrinsic efficiency because almost all the instances are useful. Furthermore, this protocol is feasible with present day techniques.

No abstract

No abstract