Wave function collapse is a process of losing the superposition information to the environment.

The remaining problem is that we still cannot predict which part of the information will be lost.

— Me@2011.11.20

In quantum mechanics, quantum decoherence is the loss of coherence or ordering of the phase angles between the components of a system in a quantum superposition. A consequence of this dephasing leads to classical or probabilistically additive behavior.

Decoherence can be viewed as the loss of information from a system into the environment (often modeled as a heat bath), since every system is loosely coupled with the energetic state of its surroundings.

That is, components of the wavefunction are decoupled from a coherent system, and acquiring phases from their immediate surroundings.

— Wikipedia on Quantum decoherence

2011.11.23 Wednesday (c) All rights reserved by ACHK