Computers are real

[Vkothii]

Speed, is a property of physical objects. Speed, or velocity, is the result of energy being applied to some object. Objects with a velocity are still objects, but their velocity can change, along with their position.
Because energy modulates both.

So, giving some object a velocity (changing its velocity) is a computation. The information (the object) is modulated by applying an energy to it. The 'signal' can be either the object, or the velocity of the object, or both. Measurement, is the bottom-line on information - what is it, where is it, what is it 'doing' or 'saying' etc.

What does this mean??:
"Information is dimensional; there is no "one-dimensional" information anywhere in the universe."

 

[Pete]

Yes, I do see.

To "create" information requires the following:

1) A collection of physical objects
2) A means of manipulating them
3) An encoding, or logical representation that gets 'mapped' over the physical collection, by the manipulations.

Therefore all information, regardless of the logical representation, requires a physical form.
Therefore "information is physical" Q.E.D.

No, Vkothii, it does not follow, except in a sense that weakens the word "physical" to meaninglessness.

Can you name anything that is not physical, according to the logic you are applying?

 

[Vkothii]

No, Vkothii, it does not follow, except in a sense that weakens the word "physical" to meaninglessness.

Can you name anything that is not physical, according to the logic you are applying?

Can you, even try to name anything that is not physical? I don't understand how I've "weakened" the sense of a word so it's meaningless??

Don't you know what "physical" means now?

BTW, if information (whatever it is) is NOT physical as you say, then we need to point out a few things to all those comms and computer people. They've been blindly following an idea which is obviously incorrect.
So how would you rewrite Shannon's theory?

 

[Enmos]

BTW, if information (whatever it is) is NOT physical as you say, then we need to point out a few things to all those comms and computer people. They've been blindly following an idea which is obviously incorrect.

How do you figure that ?

 

[Vkothii]

You seem to have a rather inverted view of what "representation" means.

How is information just logical?

Let's rephrase that. How do you logically wear sunglasses that polarize the incoming light (to your eyes)?

 

[Pete]

Can you, even try to name anything that is not physical?

Thoughts. Concepts. Ideas. Information. Knowledge.

I don't understand how I've "weakened" the sense of a word so it's meaningless??

If everything is physical, then saying that something is physical is redundant.

Don't you know what "physical" means now?

I'm not sure that you do.

BTW, if information (whatever it is) is NOT physical as you say, then we need to point out a few things to all those comms and computer people. They've been blindly following an idea which is obviously incorrect.
So how would you rewrite Shannon's theory?

I am "comms and computer people", and Shannon's theory doesn't need rewriting.

 

[Vkothii]

Thoughts. Concepts. Ideas. Information. Knowledge.

Thoughts are real. Concepts are thoughts, etc.

So, how does a pair of polaroid specs, manage to logically polarize sunlight?
I'll rephrase that for the computer-expert: what is the entropy of information, in the plane-polarized light, which the real, solid. material physical sunglasses integrates? What's the general form of this integral?

(BTW, in case you forgot, Planck's constant is real, too)

 

[Pete]

Thoughts are real. Concepts are thoughts, etc.

Yes, they are real.
No, they are not physical - they have neither mass nor energy.

So, how does a pair of polaroid specs, manage to logically polarize sunlight?

Again, you confuse the medium with the message.

 

[Vkothii]

No, they are not physical - they have neither mass nor energy.

Neurons aren't physical? electrical signals have no "mass or energy"??

Again, you confuse the medium with the message.

Nope, that's what you keep doing, and confusing the message with the medium when you transfer from one to the other.

The entropy of wearing the sunnies, has two bits in its alphabet - on or off.
What about the entropy in the alphabet of photon polarization?

What's the expectation that each particle, or signal, will be polarized as it impinges on the outside, the input as it were, either transmitted or reflected/absorbed, by these things?
You very smart guy, you know answer, huh?

 

[Pete]

:shrug:
Sorry, Vkothii.
When you confuse neurons and electrical signals with thoughts, then say that I confuse medium and message, there's no point in continuing.
Likewise when you confuse polarised light (medium) with information (message).

I'm done with this.

 

[Vkothii]

Wo ho, ah, I "confuse" neurons and electrical signals with thoughts, huh?

A photon shouldn't be confused with a message? But they use them for messages all the time, down optical fibers, not just optical; radio is long-wavelength photons.

Holy shit, this guy is some expert.


If instead of polarizing photons at optical frequencies, you did it at radio frequency, or say, microwaves, that get polarized by a waveguide in a certain way, is that information, and does it have an entropy?

 

[Vkothii]

You know about Landauer, (ir)reversible logic, what that means?
How information certainly is logical, because it has a physical representation as well (it simply would not be logical for it not to).

Landauer studied the physical limitations placed on computation from dissipation.
He was able to show that almost all operations required in computation could be performed in a reversible manner, dissipating no heat.
The first condition for any deterministic device to be reversible is that its input and output be uniquely retrievable from each other.
This is called logical reversibility, and communication is also computation.
A computer is a network of channels that communicate, reversibly and irreversibly. Each communication, in terms of any overall computation, is a trivial computation.

If, in addition to being logically reversible, a device can actually run backwards then it is called physically reversible and the second law of thermodynamics guarantees that it dissipates no heat. In practice, such a computer would only be 'allowed' to use Brownian motion, or it would have to preserve all inputs at each step (i.e not dissipate any bits of information).

On a classical computer, programs are executed by linear evolution in time, of an input that is "given to" the system which computes a state, changing (evolving) through various states, while a background "system timer" steps discretely through the states.

On a quantum computer, programs are "executed" by unitary evolution of an input that is "given by" the state of the system. Or the input is determined (measured) by the system state, (i.e. the system "measures the input", and we "measure the output").

So manipulating the state, by "stepping" through different computation bases, rather than stepping through different states within the same computation basis, is the key to quantum computing.

Since all unitary operators $$ U $$ are invertible with $$ U^{-1}= U^{\uparrow} $$, we can always "uncompute'' (reverse the computation) on a quantum computer.
Reversing the computation (a series of communications) in a classical computer means copying (remembering) all of the inputs, i.e. "keeping them around" so they don't dissipate.
A signal can be retrieved after it's been sent, by first copying it. Sending the only copy is an irreversible communication, (a computation that is locally trivial).

 

[funkstar]

Thanks funkstar, I hadn't heard of that principle.
But, it does not seem to apply to the specific point you quoted.
From what I gathered through Wikipedia (not necessarily a reliable process!), Landauer's principle does not correlate the information in a system to the mass/energy of a system. Rather, it describes a limiting case of how altering the information in a system affects the entropy of that system - essentially, it appears to dictate that manipulating information in a particular way has a real entropy cost,

Exactly. Landauer's principle tells us that the erasure of information requires the dissipation of heat.

i.e. useful work must be converted to heat.

Ah, not quite. You can do very useful work (in the computational sense, not the physical sense) without having to erase information.

In fact, this (reversible computing) is my personal field of study, Vkothii is actually not entirely off base. A lot of it is quite sensible, if presented somewhat inelegantly...

 

[Vkothii]

reversible computing is my personal field of study

You know about the principle of universal computation then?
How, without reversible communication, there wouldn't be any (communiciation, or computation). Another way to say, the universe computes reversibly, and irreversibly?

If the universe is computing, is anything in the universe NOT computing?
What's the inverse of computation? Reversible computation of course.

 

[Pete]

Yes, they are real.
No, they are not physical - they have neither mass nor energy.

I've thought about this, and returned to the thread to correct a mistake I made.
I've been drawn into misusing the word "physical" myself. I don't think that it was correct to equate "physical" with "has mass or energy".

So, I withdraw the contention that information cannot be physical, in particular interpretations. Information can be (and often is) considered to be a property of a physical object, and can thus be considered to be physical itself.

However, I continue to maintain that information does not have mass or energy. You can not say how much mass or energy is embedded in some information. The mass/energy of some object or set of objects does not depend on the information encoded within.

 

[Pete]

Hi funkstar,

Ah, not quite. You can do very useful work (in the computational sense, not the physical sense) without having to erase information.

Yes, of course.
I meant: "in order to manipulate information in a particular way [any logically irreversible manipulation]... useful work must be converted to heat."

In fact, this (reversible computing) is my personal field of study, Vkothii is actually not entirely off base. A lot of it is quite sensible, if presented somewhat inelegantly...

Not completely off base, no. But I think that he is off base when he says that information has mass/energy:

Information is physical; it has mass and energy, because it has entropy.

 

[Vkothii]

But I think that he is off base when he says that information has mass/energy:

But you would fail any question in a physics exam, if you said "information has no mass or energy".

Does mass or energy have information instead? Do you still think thoughts aren't real physical things?
(How do you think that with imaginary thoughts, exactly)?

P.S. If you ever do study IT, it's one of the first things you learn, even before you get near Shannon's limit. Information has entropy, because it has mass; mass has energy.

Or it has energy, which has "mass". There is no way around this; logical information exists, because mass/energy exists, and there is nothing anywhere that has mass/energy that isn't information as some logical 'form' - because we give it the logical form.

We don't, and we can't, give a logical form to something that doesn't exist.
Ideas exist, an idea of a horse isn't a horse, but it is a real physical representation of a horse. Substitute "anything anywhere in the universe", for "horse", and there you go.

 

[Enmos]

So let me get this straight. If we take a freshly formatted USB-stick and weigh it, then cram it full of data and weigh it again, it has gained in weight according to you ?

 

[Vkothii]

If we take a freshly formatted USB-stick and weigh it, then cram it full of data and weigh it again, it has gained in weight according to you ?

Yes, if it has extra electrons as stored charges, then it has gained 'weight', or it now has more particles, organized as discrete bits, in it.
So absolutely, it has more information entropy (which is always independent of the entropy of its physical realization).

That isn't just "according to me", btw.

 

[Diode-Man]

Computers contain information, but they will never actually "know" anything.