[varsigma (OP)]

I've recently been trying to have a discussion about the relevance of information, and what exactly is information, at another site.
It didn't really get anywhere and I found myself up against some rather fixed views. Science is meant to be about enquiry, I thought. So why are so many people not willing to examine their own beliefs and ideas, why is there so much fear about examining the possibiity that you don't "really" understand something and might need to adjust those beliefs?

But to the topic: I mentioned Landauer's principle, what it says and tried to examine whether it does pertain to erasure of information.

Well, one person who is a moderator tried to convince me that information isn't physical, so erasing it doesn't make any sense. He also appeared to believe that thoughts aren't physical, although strangely, the process of thinking, or conceiving is physical. I think that's really confused and not particularly enlightening.

So is information physical? Does the question come down to is information a pattern and can a pattern be non-physical? Moreover, is Landauer's principle true? I know it's generally accepted as true, but is that because computers are also heat engines, or are they?

Or take a look at the science of astronomy: is it just an information-gathering disciplne? how is the information gathered physically; what do humans do with this information?
How does the theory that information is not physical, fit into it?

Another question I have is, can information be characterised without the notion of a sender, a receiver, and a communications channel for transmission of signals?

[Origin]

So why are so many people not willing to examine their own beliefs and ideas, why is there so much fear about examining the possibiity that you don't "really" understand something and might need to adjust those beliefs?

Just because someone disagrees with you doesn't mean they are fearful of your idea.

[evan_au]

Information can be rather abstract, as can its counterpart Entropy.
- For example, the Entropy of a black hole increases when matter or radiation falls into it, but in theory, that information later escapes as the black hole evaporates via Hawking radiation.
- As a communications channel, a Black Hole is maximally noisy
- The "Black Hole Information Paradox" would still be relevant, even if there is no-one present to receive the information (let alone decode it).
https://en.wikipedia.org/wiki/Black_hole_information_paradox

For practical purposes, we encode information in physical objects, where:
- I am counting photons as physical objects - that's how most information on the internet is transmitted.
- I am counting magnetic domains as physical objects - that's how most information on the internet is stored.
- If Information did not have a physical form, we would not be able to read it, and the information would be lost to us.

Astronomy is a remote information-gathering exercise (at least until you can send a probe to the object, and then it becomes a more local, atom-level form of information-gathering).
- Traditionally, astronomers used visible light, but that has now been extended to many other forms of electromagnetic radiation from radio waves to gamma rays
- A lot of information is carried on gravitational waves, but that is buried in the noise, so only major events like black hole collisions can be detected with current technology
 - A lot of information is carried on neutrinos, but these ghostly particles sail straight through the Earth (and our detectors) - they are close to being non-physical, as far as we are concerned. To date, there has been just 1 supernova in a nearby dwarf galaxy discovered via neutrinos
- I am sure that a lot of information would be carried on the hypothetical Dark Matter particles, but at present we have no receiver that can detect them, so they are lost to us

To improve the efficiency of computing (especially quantum computers), some researchers are working on designs of computing that don't erase information, but store and process it.
- But we are still a long way from reaching that efficiency limit. In many ways, the human brain is much more efficient than todays silicon chips.
https://en.wikipedia.org/wiki/Landauer%27s_principle

[varsigma (OP)]

Information can be rather abstract, as can its counterpart Entropy.

I'm interested in Landauer's principle. I've studied information theory and Shannon entropy (I have a double major in math and CS)

Recently I spotted some updates--new research--that claims to refute the principle in the low-dissipation regime, that is, information was erased by resetting a memory and the heat generated was well below Landauer's limit.
Right next to this new result was an article that confirmed Landauer's limit in a quantum memory.

So now I'm asking myself, did Maxwell's demon really get "exorcised" by Charles Bennett? Is there something more fundamental about information and its erasure or loss, that everyone is overlooking? I guess the jury is still out; Hawking's paradox also has a lot of open questions; it's all theoretical I realise, actual measurements to confirm certain theoretical ideas about the nature of black hole entropy, will have to wait for some pretty clever devices to appear.

Than again, what does QM predict, about the nature of quantum information? If we knew that, why are there so many discoveries that QM hasn't predicted? For example the quantum Hall effect, certain quasiparticles that have only recently been observed, or even how small a physical object needs to be to exhibit quantum behaviour such as superposition of states? These are things that only experiments and research with new materials can answer, it seems. But why is that?

[yor_on]

What a nice question.

First of all, thoughts are definitely information, although it might not show in ones behavior :) You can't pretend that physics would exist without something defining them, and that should be laws, principles and properties. I might have missed something here but information is a very subtle subject to me.
=

I think this one touches on your thoughts.

https://arxiv.org/pdf/physics/0210005.pdf

[evan_au]

The idea of "Momentum computing" is claimed to approach the Landauer limit for simple, supercooled circuits.
- By making the computation reversible, they avoid erasing any bits
- But it is likely to be disturbed by random noise in the circuit, which scrambles momentum.
https://www.scientificamerican.com/article/momentum-computing-pushes-technologys-thermodynamic-limits

[varsigma (OP)]

I think just as a reality check, I should define my version of information.

It's a pattern, however that gets defined, in matter. Really information entropy is only given that name because of a formula that looks superficially like the one for thermodynamic entropy.

Information and its entropy is just a structure, an arrangement of particles of matter, then we decide which ones are interesting or useful. I might be going a bit far with the superficial thing, but what information is, still seems to be an open question, so that's my best answer. Patterns in nature are what motivates us to create them ourselves, type of thing; but it's all just structure of some kind that matter allows.

Shannon "only" showed that the information content is proportional to the expectation of "seeing" it. So if you arrive home and the TV is missing, that has more entropy than if it's still where you expect it to be. You see a different pattern than what you expected.

[varsigma (OP)]

It might be the case that understanding the nature of information-as-patterning could lead to insights into the nature of the workings of the human, or any animal brains. A paper I've been reading says this:

Abstract
This article reviews the preliminary results of an analysis of the brain that may supplement our
current understanding of its structure and function, even if by falsification. This analysis seems to
reveal that the information in a system of the brain can be quantified to an appreciable degree of
objective precision, that many qualitative properties of the information content of a system of the
brain can be inferred by observing matter and energy, and that many general features of the
brain’s anatomy and architecture illustrate simple information-energy relationships. It is possible
that the brain provides a unique window into the relationship between matter, energy, and
physical information.

--https://www.biorxiv.org/content/biorxiv/early/2016/07/06/060467.full.pdf