Dynamical properties of an exactly solvable coupled quantum double-well system: The evolution speed and entanglement

We have studied dynamical properties of an exactly solvable quantum coupled double-well (DW) system with Razavy's hyperbolic potential. With the use of four kinds of initial wavepackets, the correlation function Gamma(t) and the concurrence C(t) which is a typical measure of the entanglement in two qubits, are calculated. We obtain the orthogonality time tau which signifies a time interval for an initial state to evolve to its orthogonal state, and the temporal average of C-av( = root < C(t)(2)>). The coupling dependence of tau and the concurrence [C-av or C(0)], and the relation between tau and the concurrence are investigated. Our calculations have shown that the evolution speed measured by tau(-1) is not necessarily increased with increasing the concurrence in coupled DW systems. (C) 2014 Elsevier B.V. All rights reserved.