On Thu, Nov 14, 2024 at 5:27 PM Brent Meeker <[email protected]> wrote:
*>> Me: The idea of entropy is inextricably linked with information, and >>> information is physical; Landauer's principle allows us to calculate the >>> fundamental lower bound on the energy needed to erase one bit of >>> information, it is kT ln 2, where k is the Boltzmann constant and T is the >>> temperature in degrees kelvin. At room temperature it's about 2.9 x 10^-21 >>> joules per bit. That sure sounds physical to me.* >> >> > > >> *>Sounds like a theory to me. "https://arxiv.org/html/2402.15812v1"; >> <https://arxiv.org/html/2402.15812v1>* >> > > *>> Me: Sounds like a theory to me too, maybe it's true, but even if it is > I note that they include with: * > > *"**Although our erasing strategy can operate in a regime that goes > beyond the Landauer limit, the statement that the erasure of information > always produces heat still holds true. In fact, as discussed in Subsec. III > B, the memory always ends up in the ground state by releasing some amount > of heat. In this context, the present erasure protocol can also be > understood as a perfect cooling process. In this context, the present > erasure protocol can also be understood as a perfect cooling process. Our > results strengthen the view that quantum processes can surpass certain > classical thermodynamic limits, and may contribute to the progress of the > emerging field of green computing"* > > *>> So information is still physical* > > *> Chalk on a blackboard is physical too but it isn't entropy just because > you write S=kT ln(2).* > *That would be correct, the equation is irrelevant. The chalk on the blackboard is not physical just because it's used to write a particular equation, the chalk is physical because it is capable of encoding information and it is capable of interacting with other bits of information that are also encoded physically. Even one molecule of CaCO₃ can encode information because now you know that a molecule of chalk is at that one particular point in spacetime and not at some other point. * *I would say that the best definition of "physical" that I know of is that something is physical if and only if it is capable, at least in theory, of encoding information. It wouldn't be very practical but even entropy could encode information, a high entropy state could encode 1 and a low entropy state encode 0. It turns out that according to General Relativity even completely empty spacetime can have a memory, after a gravitational wave passes through a region of spacetime it does not return to exactly the same shape it had before the wave, there is a very tiny difference. * *Does space-time remember? The search for gravitational memory <https://www.newscientist.com/article/mg25934501-400-does-space-time-remember-the-search-for-gravitational-memory/> * *I think the idea of information and computation existing in some sort of a platonic heaven in the complete absence of anything physical is ridiculous; that's why I think physics is more fundamental than mathematics. * > *>> Forget many worlds forget quantum mechanics, even Newton knew that if >> you say "X measured my foot" then that implies X is consciousness, or at >> least an intelligence. If you say "X changed my foot" then X may or may not >> be conscious or intelligent. * > > > *> Then** what do you call all the decoherence implementing interactions > not involving consciousness or intelligence,* > *A change. * > > * It was my impression you called them all measurements in the past.* > *If so then that was probably because I was talking about a thought experiment, and those almost always involve an observer, and observers are conscious, or at least intelligent. A measurement is just a particular type of change. * * John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* ptc > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAJPayv3eVc98RdLEeh5Ben8cvyJ2DeAwiL%3DCwy9rBGx-KoK1BQ%40mail.gmail.com.
