A Phenomenon of Decoherence Induced by Chaotic Environment

By means of numerical simulation, we reveal a phenomenon which is due to decoherence induced by chaotic motion of a large environment. We study the possibility of replacing the environmental components of the state vector of the total system by some randomly-chosen vectors in the Hilbert space of the environment when decoherence has happened. It is shown that, in the future evolution, the reduced density matrices obtained in this way are quite close to those computed from the exact, continuous Schrödinger evolution of the total system. Similar results are also found in the case that the Hamiltonian is changed at the time of replacing components.