Add this Tag for questions on information theory applied to physics, especially in the fields of statistical mechanics and thermodynamics, the black hole information paradox, complexity of dynamical and physical systems and questions to do with whether information is conserved by physical systems. ...

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17
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2answers
2k views

What do physicists mean by “information”?

On the question why certain velocities (i.e. phase velocity) can be greater than the speed of light, people will say something like: since no matter or "information" is transferred, therefore the ...
1
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1answer
37 views

Information in twisted light

New Scientist has a story on the use of twisted light to store multiple bits of information per photon. What is this technology, and what are the information density limits per photon? "MOZART and ...
1
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2answers
47 views

How do we represent 'smell' and 'taste' as signals?

I was wondering if we could represent 'smell' and 'taste' as signals like we do for audio. How do we mathematically represent them? Is there any research papers related to it? Can someone give me ...
3
votes
1answer
43 views

Is there a lower bound on energy needed to transfer one bit of information?

Let's say we want to transmit information between to stations (points in space). Is there a minimal energy required to transfer a single bit of information, assuming that we tolerate that the bit ...
31
votes
5answers
3k views

What is the most efficient information storage?

What is the most efficient way to store data that is currently hypothesized? Is it theoretically possible to store more than one bit per atom? Until Floris' comment, I hadn't considered that ...
0
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0answers
33 views

Arrow of Time in Information transfer

I am writing a sci-fi script and need some legitimate theory to back up a central story element (so there's no real world application): Could there be a logically consistent theory supporting the ...
2
votes
2answers
77 views

Minimum information necessary to represent a pure quantum state

I was thinking about how quantum states are represented for various types of systems, and how the amount of classical information (bits) required to represent a state depends on its basis. Let's take ...
0
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0answers
44 views

Is spacetime information?

As I understand it, the information in a system is the totality of its properties that make its state uniquely identifiable. Examples I've seen are things such as the spin of each particle within the ...
2
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0answers
45 views

Consequences of Entropy/Information Reversal in a System?

Can pairs of different physical systems be symmetrical under a process which would turn one of these physical system's entropic and informational contents into another system's respective ...
2
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0answers
62 views

How can physics claim that information cannot be destroyed? [duplicate]

I watched a video featuring Leonard Susskind in which he took a small bowl of water and added three drops of food coloring. He swirled it around. At first you could tell where the drops must have ...
28
votes
4answers
3k views

Why do computers generate heat?

Computers generate heat when they work. Is it a result of information processing or friction (resistance)? Are these just different ways to describe the same thing? Or does some definite part of the ...
1
vote
1answer
20 views

Can data be transmitted from one object to another one during electrostatic discharge (ESD)?

Did this ever happen to you?, after you touch something (or someone) 'Ouch'! you get a static electric shock. Can (any kind of) information be transmitted between two people during accidental ...
3
votes
2answers
131 views

Why the self-information is -log(p(m))?

Why is self-information given by $-\log(p(m))$? Shannon derived a measure of information content called the self-information or "surprisal" of a message $m$: $$I(m) = \log \left( ...
1
vote
3answers
87 views

Is there a minimum energy content of information, other than 0 Joules?

Lets say I want to send the bit string 010110 to someone. Is there a theoretical lower bound on the energy needed to do this?
3
votes
2answers
96 views

Bekenstein bound for electron?

Using the Wikipedia version of the Bekenstein bound, and substituting the Wikipedia values for electron mass and radius, one obtains 0.0662 bits. Does this really mean that a system, any system, ...
0
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0answers
21 views

Information of things inside a black hole [duplicate]

Can we get the information of things that are gone in black hole?
0
votes
0answers
10 views

What is the maximum theoretical limit on how much a HDD can store [duplicate]

I was wounding what was the maximum theoretical limit on how much a HDD(with 5 platters and a 3.5 inch size drive) can store because they have 6TB (not to be confuse with TiB) Because most people do. ...
4
votes
2answers
217 views

Is this theory about Universe and information true?

I recently saw this video about information and randomness. At some point, it states that a completely predictable universe would infringe the second law of thermodynamics, because it would imply that ...
2
votes
2answers
53 views

Superimposed state vs. zero amplitude state

Two equal amplitude wave pulses approaching each other through some medium such as a string may form a region of zero amplitude when they overlap completely. At this point, the location of overlap is ...
0
votes
1answer
93 views

Are only 2 bits of information transmitted in quantum teleportation?

Prompted by the recent success in Delft, I've been reading a number of papers and articles about quantum teleportation. I'm comfortable with my understanding of most aspects but haven't found much ...
0
votes
1answer
49 views

Change of variables in calculating the integral of multivariable differential entropy

I have already asked this question in math.SX but here might be more proper. So I decided to put a copy here and delete the one which is not the one that got an answer: I know that for one ...
0
votes
1answer
62 views

Information faster than light? [duplicate]

Imagine that you have two typewriters on the other side of the galaxy. Their typebars are connected by ropes (stretched to the maximum), so anything you type will instantly appear at the second ...
1
vote
1answer
55 views

How does information about charges propagate through the electromagnetic field

I understand how the wave equation works, and therefore how light moves through the EMF; this question is not about that mechanism. But when a charge moves in space, information about its location ...
0
votes
0answers
60 views

entropy in Information theory vs thermodynamic?

We Now From Information Theory That Entropy Of Functions Of A Random Variable $X$ Is Less Than Or Equal To The Entropy Of $X$. Does It Break The Second Law Of Thermodynamic?
5
votes
2answers
104 views

How can the microstates be measured with zero energy expenditure?

James P. Sethna. Statistical Mechanics. Exercise 5.2: What prevents a Maxwellian demon from using an atom in an unknown state to extract work? The demon must first measure which side of the ...
3
votes
1answer
117 views

Definition of Information in Information Theory

I am not sure in which SE site I have to put this question. But since I have learnt Shannon Entropy in the context of Statistical Physics, I am putting this question here. In the case of Shannon ...
19
votes
5answers
2k views

Where does deleted information go?

I've heard that, in classical and quantum mechanics, the law of conservation of information holds. I always wonder where my deleted files and folders have gone on my computer. It must be somewhere I ...
0
votes
3answers
117 views

Can matter be converted to information?

I know that matter can be converted to energy through E=mc^2. I also know that engery can be and has been converted to information through Landauer's principle (with Maxwell's demons). Does this ...
1
vote
3answers
196 views

Quantum entanglement: does it necessarily imply superluminal information transfer? [duplicate]

From what I understand, information is communicated instantly between two quantum-entangled particles regardless of the spatial distance between them. However, does this necessarily imply superluminal ...
1
vote
0answers
110 views

Do black holes exist? [duplicate]

Do black holes exist from our point of reference? From our point of reference nothing actually goes inside the event horizon right? So is there anything inside the event horizon from our reference? If ...
4
votes
0answers
151 views

No hair theorem and black hole entropy

The no hair theorem says that black holes rapidly converge to a state that is completely described just by their mass, spin and charge. Black hole thermodynamics says that the black hole entropy is ...
2
votes
1answer
169 views

If distant observers never see a black hole form in finite time how can the information paradox be a problem?

So, at least as reported in the media, the physics community is still struggling with the problem of resolving the impossibility of retrieving information from beyond the event horizon of a black hole ...
13
votes
1answer
426 views

In there such a thing as the Black Hole Information Paradox?

When I first heard about the black hole information paradox, I thought it had no content. At the time, papers about it had been written for numerous years and they keep on coming. Now that the press ...
1
vote
1answer
113 views

Information content of the expanding Universe

As I understand, in physics, 'information' is closely tied to thermodynamic entropy. Does this relationship imply that if the Universe expands and ends in 'heat death' (maximum entropy?) that it ...
0
votes
1answer
105 views

Is Information a potential or kinetic kind of energy?

It is said that the law of least action is that nature tries to convert potential energy into kinetic one as fast as possible. Information can't be thought without a physical realisation, see here. ...
10
votes
2answers
278 views

Would the horizon of a black hole be different for a tachyon than for subluminal matter or photons?

One of the most useful black hole analogies I've seen imagines that space is "flowing" like a river into a black hole, and the point at which it flows in faster than c is the horizon. This analogy ...
1
vote
3answers
157 views

Are communications between computers faster by electrical signals via copper cables or electromagnetic signals?

Assume that there are two computers which are connected with a copper cable, e.g. Ethernet. Also, there is a radio connection between them, e.g. AM radio, in order to exchange data. When we try to ...
1
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0answers
48 views

Information and Black holes

From Youtube: A Thin Sheet of Reality: The Universe as a Hologram (Full) I have a few questions: Why there are not layers of information on a black hole? If the information is stored in the ...
5
votes
2answers
144 views

Proof of conservation of information [duplicate]

After listening of some lectures of Leonard Susskind about black holes, he mentioned that conservation of information is one of the foundations of physics. After searching the web I cannot seem to ...
9
votes
3answers
2k views

How are physics and computer science getting united?

How is theoretical computer science getting united with physics? Phenomena like Quantum Computing uses Quantum Mechanics to be able to compute things, how are computers helping not just to model our ...
3
votes
1answer
100 views

Do monochromatic waves carry information?

The answer is negative according to http://www.mathpages.com/home/kmath528/kmath528.htm It should also be remembered that a perfectly monochromatic wave carries no information, and therefore is ...
1
vote
1answer
124 views

What does “Information” and Virtual Particles mean?

I've read that attraction and repulsion between particles is caused by the exchange of virtual photons, and that virtual photons carry information. I don't understand how a virtual photon actually ...
0
votes
1answer
95 views

Discord for partially decohered bell state

To illustrate discord and its use, Zurek in his paper on discord (NB pdf) gives example of a partially decohered bell state i.e. $$\rho_{AB}=\frac{1}{2}(|00\rangle\langle 00|+|11\rangle\langle 11|) + ...
1
vote
2answers
104 views

How irreversible processes are possible?

Susskind says that all laws of mechanics are reversible and any valid mechanic law most be reversible: you can always determine the previous state of any physically valid system. However, the simplest ...
11
votes
1answer
391 views

How many bits are encoded on the surface of the smallest black hole?

Here's my guess ($157\, \textrm{bits}$) and how I got there. Please feel free to disregard completely and give your own answer. My understanding (please correct any wrong assumptions as there may be ...
0
votes
1answer
82 views

Why are waves, the means, of information transfer over long distances, excluding difusion or contact of info stored in matter

Practical long distance communication, which does not rely on the movement of encoded configurations of matter, from source to destination(odor,books,DNA,floppy disk), always involves waves (EM, ...
5
votes
3answers
235 views

Does unitarity imply conservation of energy?

Not too long ago, someone began to discuss the thinking and motivation behind the Lagrangian and its formalism for the Newtonian framework and an intuitive understanding of such formalism. Somehow, it ...
-2
votes
1answer
86 views

Is information propagated across a medium in any other way than waves?

Is information propagated in any other way than waves? Please distinguish "propagation across a medium" from information "storage within stable states of matter", which might difuse or interact ...
5
votes
1answer
312 views

How does Landauer's Principle apply in quantum (and generally reversible) computing

I understand that a reversible computer does not dissipate heat through the Landauer's principle whilst running - the memory state at all times is a bijective function of the state at any other time. ...
3
votes
1answer
311 views

Should entropy have units and temperature in terms of energy? [duplicate]

I've been thinking about entropy for a while and why it is a confusing concept and many references are filled with varying descriptions of something that is a statistical probability (arrows of time, ...