3. Philder wrote:

Is there any loss of information during decoherence? Is there any phenomena that we know of that imply a real loss of information?

In standard quantum mechanics, decoherence implies that the system considered is not closed, but interacts with the environment. Thus, while there is a leak of quantum information from the system into the environment, information is still conserved in the embedding universe.

Still, the possibility of a fundamental information loss cannot be completely ruled out and is explored in alternative theories.

Thanks for this very good article.
Sometimes life is full of coincidences. I was just thinking “it’s been a long time since I haven’t looked at strangepaths.com” and what do I read on the first page: exactly the stuff I’ve been reading about during the past few weeks.

I’m not very familiar with quantum mechanics so I have a question about it. Is there any loss of information during decoherence? Is there any phenomena that we know of that imply a real loss of information?

That “any irreversible computation may be transformed into a reversible one” does not insure that its the same for nature [..] Perhaps you could clarify.

Natural laws are fully reversible, up to all current evidence. This means that fundamentally there is no irreversibility to begin with. All phenomena would be already embedded in a reversible whole, where all information is conserved, and only parts of the whole would behave irreversibly, by their interaction with other parts. See also Loschmidt’s paradox.

In [..] the phrase, “a physical system performs an irreversible computation” . Is the ‘physical system’ a computer doing a computation or is the computation done by nature to guide whatever physical system is being observed?

It is a physical system doing a computation (that is, a computer).

That “any irreversible computation may be transformed into a reversible one” does not insure that its the same for nature: seems the making of reversible from irreversible is dependent on the programmer! Perhaps you could clarify.

In the same vein can you clarify the phrase, “a physical system performs an irreversible computation” . Is the ‘physical system’ a computer doing a computation or is the computation done by nature to guide whatever physical system is being observed?