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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1answer
158 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 ...
5
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2answers
200 views

Information Loss in annihilation

The concept of information loss is usually discussed with respect to a black hole. My understanding is that whatever matter you put into the black hole, it has only 3 "hairs" and so one doesn't know, ...
0
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1answer
197 views

How is there a connection between energy and information?

http://physicsworld.com/cws/article/news/2010/nov/19/information-converted-to-energy In the last part of the third paragraph of the above article it says: "In fact, Szilárd formulated an equivalence ...
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2answers
238 views

Entropy: two explanations for the same quantity?

I studied thermodynamics and I saw the following definition for entropy: $$ \Delta S = \int_1^2 \frac{\text{d}Q}{T} $$ that we use to calculate $\Delta S$ for different types of transformations. In ...
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3answers
181 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 ...
5
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1answer
541 views

Is there really time reversibility in physics?

First, how i got to the question. I was randomly looking at this page: http://en.wikipedia.org/wiki/Langton%27s_ant describing some sort of cellular automaton. Here is the path of this automaton ...
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2answers
250 views

What is the mechanism for fast scrambling of information by black holes?

Sekino and Susskind have argued that black holes scramble information faster than any quantum field theory in this paper. What is the mechanism for such scrambling?
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2answers
124 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 ...
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2answers
2k views

What is the relationship between Energy, Entropy, and Information?

What is the relationship between Energy, Entropy, and Information? I read this - What Is Energy? Where did it come from? - and the top answer says that 'energy' is an abstract number that is a ...
3
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2answers
248 views

Number of bits needed to express physical laws?

What is the minimum number of bits that would be needed to express a given physical law, like the law of universal gravitation? How many bits are needed to express each of the four fundamental forces? ...
3
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1answer
278 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 ...
24
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5answers
2k views

Why is information indestructable?

I really can't understand what Leonard Susskind means when he says that information is indestructible. Is that information that is lost, through the increase of entropy really recoverable? He ...
6
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3answers
392 views

Confusion regarding entropy, reference papers request

1.a In paragraph at Wikipedia/Entropy it is stated: This is because energy supplied at a high temperature (i.e. with low entropy) tends to be more useful than the same amount of energy ...
2
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1answer
143 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
151 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 ...
0
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2answers
126 views

sending information over a wire--mechanically [duplicate]

Possible Duplicate: Is it possible for information to be transmitted faster than light? I've thought about this since I was a little kid. I know it isn't exactly feasible, but it still ...
5
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3answers
293 views

Information loss in a black hole

How does the Holographic Principle help to establish the fact that all the information is not lost in a black hole?
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2answers
787 views

How is information related to energy in physics?

I recently attended a talk by Dr. Ravi Gomatam on 'quantum reality', where the speaker suggested, that conservation of energy is not a fundamental law, and is conditional, but the conservation of ...
12
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4answers
789 views

Ignorance in statistical mechanics

Consider this penny on my desc. It is a particular piece of metal, well described by statistical mechanics, which assigns to it a state, namely the density matrix $\rho_0=\frac{1}{Z}e^{-\beta H}$ ...
1
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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
505 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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1answer
210 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 ...
6
votes
1answer
298 views

What is the information geometry of 1D Ising model for a complex magnetic field?

Consider the one-dimensional Ising model with constant magnetic field and node-dependent interaction on a finite lattice, given by $$H(\sigma) = -\sum_{i = 1}^N J_i\sigma_i\sigma_{i + 1} - h\sum_{i = ...
21
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3answers
212 views

Does entropy measure extractable work?

Entropy has two definitions, which come from two different branches of science: thermodynamics and information theory. Yet, they both are thought to agree. Is it true? Entropy, as seen from ...
3
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1answer
335 views

Microsecond trading with neutrinos

The Spread Networks corporation recently laid down 825 miles of fiberoptic cable between New York and Chicago, stretching across Pennsylvania, for the sole purpose of reducing the latency of ...
1
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1answer
120 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, ...
8
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1answer
400 views

How is information defined from a thermodynamics point of view?

How is information defined from a thermodynamics point of view ? I came across some definitions using the concept of free energy of a system. If I have information stored in a finite volume of space ...
3
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1answer
371 views

How large is the information collected from an inverse femtobarn of collisions?

I ran into this while looking at measures of humongous amounts of data. How does the information (data) collected in an inverse femtobarn exposure compare to a gigabyte of data ?
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2answers
362 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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5answers
1k views

How is thermodynamic entropy defined? What is its relationship to information entropy?

I read that thermodynamic entropy is a measure of the number of microenergy states. What is the derivation for $S=k\log N$, where $k$ is Boltzmann constant, $N$ number of microenergy states. How is ...
3
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0answers
103 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, ...
5
votes
1answer
470 views

Why isn't black hole information loss this easy (am I missing something basic)?

Ok, so on Science channel was a special about Hawking/Susskind debating black holes, which can somehow remove information from the universe. A) In stars, fusion converts 4 hydrogen into 1 helium, ...
5
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2answers
229 views

What reflective media do laser shows use?

I am having a hard time in finding out what exact light media laser shows use. I am trying to build a laser show myself. I know that the laser light is reflected off these particles in such a way that ...
7
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7answers
7k views

Why is the decibel scale logarithmic?

Could someone explain in simple terms (let's say, limited to a high school calculus vocabulary) why decibels are measured on a logarithmic scale? (This isn't homework, just good old fashioned ...
4
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2answers
159 views

Knotted token-ring network

Suppose we have a rigid token-ring network. An observer at any node can seemingly determine the angular momentum of the network by measuring the time it takes for a packet to travel around the ring ...
7
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2answers
1k views

How many bytes can the observable universe store?

Is the number of states in the Universe countable? What framework could be used to answer the question in the title?
36
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5answers
2k views

What is information?

We're all familiar with basic tenants such as "information cannot be transmitted faster than light" and ideas such as information conservation in scenarios like Hawking radiation (and in general, ...
27
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3answers
12k views

Maximum theoretical data density

Our ability to store data on or in physical media continues to grow, with the maximum amount a data you can store in a given volume increasing exponentially from year to year. Storage devices continue ...
8
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3answers
1k views

How efficient is a desktop computer?

As I understand it (and admittedly it's a weak grasp), a computer processes information irreversibly (AND gates, for example), and therefore has some minimum entropy increase associated with its ...
6
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3answers
1k views

Maxwell's Demon Constant (Information-Energy equivalence)

New Scientist article: Summon a 'demon' to turn information into energy The speed of light c converts between space and time and also appears in e=mc^2. Maxwell's Demon can turn information supplied ...