Decoherence

Definition

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.

Context

In quantum mechanics, we appeal to Decoherence as a process that explains the emergence of a quasi-classical order. Decoherence has no classical counterpart. Moreover, it is an apparently irreversible process. Decoherence and quantum entanglement are two physical phenomena that tend to go together. The former relies on the latter, but the reverse is not true. Two particles can become entangled by just interacting with each other. See the wiki page on "Entropy Problems" for a discussion of the boundary conditions that determine the flow of time and whether Decoherence of an Entangled State has a foundational roles in the origin of time.

Problems

1. Decoherence is stochastic, not deterministic. The result is not determinable in advance.
2. Classical physics is deterministic and most physicists seem to think that feature is important to retain.

Solutions

1. Everett's solution while working with Wheeler as to say that all of the solutions happens in the many worlds that branched off from each decision.
2. Hawking's solution, as reported by Hertog,