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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0
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2answers
663 views

Qubit (Qdit) equivalence with bits/bytes/Kbytes/

What is the conversion factor for qubits (qudits) to bits/bytes in classical information theory/computation theory? I mean, how can we know how many "bits/bytes" process, e.g., a 60 qubit quantum ...
75
votes
1answer
3k views

Is it necessary to consume energy to perform computation?

As far as I know, today most of the computers are made from semiconductor devices, so the energy consumed all turns into the heat emitted into space. But I wonder, is it necessary to consume energy ...
9
votes
3answers
771 views

Are Electromagnetic Waves The Only Means of Transmitting Information?

We've been using EMF to transmit energy (information) for over a century. I was wondering is there any other way to send a message on long distances, even faster than EMF waves can travel? For example ...
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 ...
6
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0answers
191 views

Estimating the Kolmogorov Complexity of the Standard Model

The Kolmogorov complexity of a hypothesis / theory / model is the shortest computer program that simulates it, regardless of how inefficient executing that program may be in terms of memory and time. ...
5
votes
2answers
250 views

Why isn't data lost when sent over large distances?

I was thinking about how information is sent, for example through the atmosphere. There are plenty of obstacles, as well diffraction, etc. Still, no information is lost. How is information sent to ...
6
votes
2answers
1k views

What is the real-world significance of the Bekenstein bound?

The Bekenstein bound sets the maximum amount of information that can be contained in a region of space/energy, and is usually referred to in the same way as computer storage density: For example, ...
1
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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 ...
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 ...
9
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2answers
8k views

Maximum theoretical bandwidth of fibre-optics

Ignoring hardware at either end and their technological limitations, what is the maximum theoretical bandwidth of fibre optic cables currently in use / being deployed in a FTTH type situations? I ...
3
votes
2answers
417 views

Quantum Teleportation Fidelity

I understand that quantum teleportation fidelity is the overlap of the initial quantum state with the teleported quantum state. If the teleportation is perfect, then the fidelity would equal 1 or 100% ...
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?
3
votes
3answers
177 views

The role of context in information theory

Consider Hofstaedter’s jukebox analogy: A jukebox that contains only one record, but many different record players, each of which interprets that one record in a different way to produce an entirely ...
1
vote
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 ...
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 ...
1
vote
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 ...
4
votes
4answers
632 views

Uncertainty Principle for Information?

I'm not familiar (yet) on how Information theory can be emerged/used in QM/QFT but I was thinking about this question: While we have Heisenberg uncertainty principle on measuring coupled observables, ...
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 ...
1
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 ...
5
votes
2answers
224 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
votes
1answer
258 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 ...
4
votes
2answers
266 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 ...
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 ...
5
votes
1answer
626 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 ...
4
votes
2answers
279 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?
0
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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 ...
6
votes
2answers
3k 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
votes
2answers
262 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
votes
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 ...
31
votes
6answers
3k views

Why is information indestructible?

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
votes
3answers
439 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
votes
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
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 ...
0
votes
2answers
131 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
votes
3answers
317 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?
7
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2answers
1k 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
votes
4answers
906 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 $\rho_0=\frac{1}{Z}e^{-\beta H}$ ...
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
votes
1answer
625 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.
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 ...
6
votes
1answer
321 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
votes
3answers
257 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
votes
1answer
349 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
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, ...
8
votes
1answer
438 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
votes
1answer
395 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 ?
1
vote
2answers
373 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 ...
8
votes
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
votes
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, ...
5
votes
1answer
505 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, ...