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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3
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1answer
291 views

Wasn't the Hawking Paradox solved by Einstein?

I just watched a BBC Horizon episode where they talked about the Hawking Paradox. They mentioned a controversy about information being lost but I couldn't get my head around this. Black hole ...
3
votes
2answers
130 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( ...
3
votes
1answer
95 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 ...
3
votes
1answer
276 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, ...
3
votes
1answer
111 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 ...
3
votes
0answers
90 views

What is the entropy of a string?

In his The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics (p. 373) Susskind states that the entropy of a string is [...] proportional to its length. ...
3
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0answers
106 views

What is the energy conversion efficiency of a computation device like a modern CPU? [duplicate]

Possible Duplicate: How efficient is a desktop computer? I believe the energy conversion efficiency of a modern CPU is extremely low, because it dissipates pretty much all of it as heat, ...
2
votes
1answer
159 views

Reference paper to support information — energy relation ($kT \ln2 \rm\frac{J}{bit}$)

In answer to Maxwell's Demon Constant (Information-Energy equivalence) there is stated that one bit of information allows to perform $kT \cdot \ln2$ Joules of work. Which paper supports the ...
2
votes
2answers
1k views

Are information conservation and energy conservation related?

as evident from the title, are both, conservation of energy and conservation of information two sides of the same coin?? Is there something more to the hypothesis of hawking's radiation other than ...
2
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1answer
104 views

Physical structures that trap information

I labeled this question "soft" because it might not make any sense. Anyway, what I'm wondering is if there's a notion in physics that deals with the ability of matter to trap information. For ...
2
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1answer
149 views

Reconstruction of the initial state from Hawking radiation?

I hear that unitary evolution and information conservation must imply that information about information content that defines the initial state of matter used to create a black hole can be inferred ...
2
votes
1answer
82 views

Why can a qbit be used as a classical bit if information about the measurement axis is needed?

If Alice wants to send one bit of classical information she can use a qbit. Then Bob needs to know which axis to measure to get the information. This needs an extra agreement between Alice and Bob ...
2
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1answer
149 views

Thermodynamics and cross entropy

I am facing with the concept of cross entropy. I would like to know the thermodynamic and statistical meaning of cross entropy (if exists)?
2
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1answer
627 views

Physics of the Internet? [closed]

Is there a way to describe the Internet in terms of a physics theory, like how the atom is described by quantum mechanic? If there is, how is it described by this theory.
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0answers
36 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
votes
0answers
59 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 ...
2
votes
2answers
86 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, ...
2
votes
1answer
156 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 ...
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vote
2answers
374 views

Restrictions on defining microstates (Entropy)

If we have an isolated system $Sb$ with thermodynamic entropy $Eb=X$ (and growing by the 2nd law of thermodynamics), we could define an abstract system $Sa$ (containing the system $Sb$) but define ...
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vote
3answers
150 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 ...
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3answers
84 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?
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3answers
170 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
2answers
103 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 ...
1
vote
1answer
144 views

What is the information content of a human being?

How much memory would we need to represent a human? How would each atom be stored as? Bytes? Something more complex?
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1answer
255 views

Do laws of thermodynamics have a place in Theory of Everything? [closed]

I am having a difficulty understanding why second law of thermodynamics is still a valid universally accepted concept. I understand it works on paper for describing isolated heat systems. However, I ...
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2answers
51 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 ...
1
vote
1answer
121 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 ...
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1answer
144 views

Information loss

First time poster! I just burnt a piece of paper containing a 5 digit number I made up randomly and as far as I am concerned no one else will ever be able to retrieve the information contained on ...
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vote
1answer
135 views

Waves and information

I'm looking to transfer very simple information using audio waves. One of the approaches I'm looking into is using different frequencies. For example, "command 1" will be transmitted using 500Hz wave, ...
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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 ...
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1answer
101 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 ...
1
vote
1answer
253 views

An explanation for the Landauer's principle

Has anyone understood the Landauer's principle? What is the current status? In specific, is there a theoretical derivation of the Landauer's Principle?(not the heuristic one based on Salizard's ...
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vote
1answer
173 views

OAM states for wireless communications

Can someone give me an overview of how OAM states are used in communications? Using Orbital Angular Momentum States seems like a hot topic for communications. I read a few articles about the basic ...
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1answer
18 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 ...
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vote
2answers
44 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 ...
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0answers
108 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 ...
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vote
0answers
47 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 ...
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0answers
38 views

Information-theoretic limits in observational astronomy

It seems to me that with ever larger and better telescopes and powerful statistical methods, humans are gleaning surprising amounts of information from observations of distant stars. I am especially ...
1
vote
1answer
218 views

Maxwell's Demon bug, trapdoor space and time

What about the size of the door (space) and how long has it to be opened (time)? I think Maxwell's demon would have a problem with space, if the door is too wide (more than one particle size), then ...
0
votes
1answer
103 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. ...
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votes
3answers
288 views

Has anyone ever tried to formulate physics base on computer science or Information processing?

Some physicists and university researchers say it's possible to test the theory that our entire universe exists inside a computer simulation, like in the 1999 film "The Matrix." In 2003, University ...
0
votes
1answer
234 views

Is omniscience impossible?

I remember reading a brief note in Scientific American years ago about a mathematician/physicist who had published a paper that formally stated that no entity could both participate in a given system ...
0
votes
1answer
50 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 ...
0
votes
3answers
108 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 ...
0
votes
3answers
186 views

If a star were to suddenly dissapear, would it still have gravity?

I am wondering whether or not literally anything can travel faster than the speed of light. For example, if gravity from a star immediately ceases to have an effect if it suddenly and magically ...
0
votes
2answers
132 views

From what we know about QM and Elements could we simulate the Universe in a Computer?

From what we know now about Quantum Mechanics and Elements, could we simulate life the Universe at a Quantum to Element level? If we can't assume enough to create a sim, what fundamentals are we ...
0
votes
1answer
40 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
93 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|) + ...
0
votes
1answer
81 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, ...
0
votes
1answer
127 views

Question on communication between universes in a level 1 multiverse

Can matter, energy, or information travel from one universe to another in a Level I Multiverse? That is, is there any communication between Hubble volumes in an eternal inflation-induced multiverse?