Review of Short Phrases and Links|
This Review contains major "Entropy"- related terms, short phrases and links grouped together in the form of Encyclopedia article.
- Entropy is a concept in thermodynamics (see thermodynamic entropy), statistical mechanics and information theory.
- Entropy is a measure of disorder: cells are NOT disordered and so have low entropy.
- Entropy is a measure of evenness of a distribution of energy between parts of a system.
- ENTROPY is a measure of the unavailability of energy in a substance.
- Entropy is a measure of the amount of disorder in a system, and an entropic force would tend to move things toward the most disorderly arrangement.
- Thus, in the Carnot cycle, which is reversible, there is no change in the total entropy.
- Mixing paradox: On the change of entropy of a system before and after mixing.
- The average information going across the channel, the entropy, goes down, with no relationship to the amount of energy needed to cut the wire.
- In this experiment, a direct relationship between information and another physical property, entropy, is demonstrated.
- Thus, we would expect there to be some relationship between temperature and entropy.
- In this paper a unified formulation of subsethood, entropy, and cardinality for interval-valued fuzzy sets (IVFSs) is presented.
- As a consequence, lower bounds for the topological entropy of transitive graph maps in terms of the cardinality of their splittings are obtained.
- It includes a calculation of the entropy of black holes.
- The possibility for application of the proposed approach to the calculation of quantum entropy of a black hole is considered.
- One of the results that is of most interest is his outline of the calculation of black hole entropy by counting states.
- Duality predicts that the entropy of these black holes is related to the quartic invariant of the E(7,7) group.
- By the Aether Wave Theory the same duality exist between the energy and entropy, as between potential and kinetic energy.
- One must take care in trying to apply properties of discrete entropy to differential entropy, since probability density functions can be greater than 1.
- One measure which does so is the discrete entropy.
- Often, information entropy is measured in shannons, whereas the (discrete) storage space of digital devices is measured in bits.
- The following is a list of additional definitions of entropy from a collection of textbooks.
- Entropy has a precise definition within physics: it refers to the concentration or dispersal of energy at a molecular level.
- Since a finite universe is an isolated system then, by the Second Law of Thermodynamics, its total entropy is constantly increasing.
- But entropy is increasing as the universe evolves, just like the Second Law of Thermodynamics says it should.
- When heat is added to a system at high temperature, the increase in entropy is small.
- Calculating the entanglement entropy between spatially separated regions allows us to probe the topological order in Laughlin and Moore-Read states.
- Besides this, the law predicts that the entropy of an isolated system always increases with time.
- Having each "causal patch" become a separate universe allows each universe to contract essentially empty of matter and entropy.
- If you took all of the matter in our observable universe and made one big black hole, the entropy would be about 10 120.
- The entropy is normalized by the variance of the component, so absolute scale doesn't matter.
- Thus, part of the fluid system's mass is transferred without any energy transfer (since the superfluid has zero entropy).
- Using the first law of black hole mechanics, it follows that the entropy of a black hole is one quarter of the area of the horizon.
- However, the entropy from the previous cycle is spread to regions beyond the horizon during the period of dark energy domination.
- The generic patch contains no quark, lepton or force carrier only dark energy and its entropy thereby vanishes.
- The only way to understand the origin of entropy is to understand the origin of the universe -- by asking what happened at the Big Bang, and even before.
- A corollary holds the initial singularity to have minimum entropy which then rapidly increases during the first moments of the Big Bang.
- Frampton and Baum circumvent the Big Bang by postulating that, at the turnaround, any remaining entropy is in patches too remote for interaction.
- A key measure of information in the theory is known as entropy, which is usually expressed by the average number of bits needed for storage or communication.
- The entropy associated with these degrees of freedom matches with the Wald entropy for the theory.
- This results in an "entropy gap" pushing the system further away from equilibrium.
- The entropy of a system is related to the amount of information it contains.
- For molecular systems, uncertainty is closely related to entropy and hence has clear connections to the Second Law of Thermodynamics.
- This principle is vitally important to understanding the behavior of a quantity closely related to energy, called entropy.
- Fisher introduced the concept of Fisher information in 1925, many years before Shannon 's notion of entropy.
- Information entropy is available as a measure of statistical dispersion, but no notion of standard deviation or the like exists.
- In his recently developed theory of free probability and free entropy, Voiculescu introduces a notion of free entropy dimension.
- If you own a textbook with data for enthalpy and entropy, you can use this equation to predict whether or not a chemical reaction can proceed spontaneously.
- According to Equation (2) entropy falls as the temperature from the hot combustion source, T H, increases.
- In addition, the reduction of complexity, Q, reduces the entropy due to the second term in Equation (29).
- Mathematically, a coin flip is an example of a Bernoulli trial, and its entropy is given by the binary entropy function.
- He knew how the entropy of the radiation had to depend mathematically upon its energy in the high-frequency region if Wien's law held there.
- For example, a fair coin flip (2 equally likely outcomes) will have less entropy than a roll of a die (6 equally likely outcomes).
- The said quantity is amount of entropy that may be increased without changing an internal energy or increasing its volume.
- The entropy of a system depends on its internal energy and the external parameters, such as the volume.
- Here, U is internal energy, T is temperature, S is entropy, p is pressure, and V is volume.
- Entropy and generators for locally compact subshifts, Ergod.Th.
- It is believed that free entropy dimension of the generators of a factor of type II 1 is closely related to the minimal number of generators of the factor.
- All the bits of the input string are assumed to be equally random, even though the entropy present in the random source may be limited.
- A known configuration of classical fields has zero entropy: there is nothing random about electric and magnetic fields, or gravitational waves.
- In information theory, the cross entropy between two probability distributions measures the overall difference between the two distributions.
- Entropy is maximized when the probability distribution is uniform.
- The fluctuation theorem is a statement concerning the probability distribution of the time-averaged irreversible entropy production , denoted.
- The subkey generation process is designed to preserve the entire entropy of the key and to distribute that entropy uniformly throughout the subkeys.
- In a cryptosystem, entropy is the amount of disorder or randomness present in a key or in the phrase used to generate a key.
- The strength of the encrypted text is determined by the entropy, or degree of uncertainty, in the key and the algorithm.
- If, in addition, there are mass flows across the system boundaries, the total entropy of the system will also change due to this convected flow.
- Law #2 (Entropy): All things (mass and energy) tend toward disorder.
- Hence the surface area of a black hole is directly proportional not only to its entropy, but to its time dimension and its mass as well.
- Therefore, Jacob Bekenstein proposed that a black hole should have an entropy and that it should be proportional to its horizon area.
- A calculation within Chern-Simons theory leads to the desired result for the entropy, proportional to the horizon area.
- LQG may or may not be viable as a refinement of either gravity or geometry; entropy is calculated for a kind of hole which may or may not be a black hole.
- This effect of gravity has allowed the entropy of the universe to fall from its initial high value which was due to the unitial temperature uniformity.
- Since Bekenstein and Hawking computed the entropy of a black hole, this computation has become a crucial litmus test for any theory of quantum gravity.
- But the entropy was lower in the past, and to understand that empirical feature of the universe we have to think about cosmology.
- Any questions?" Actually, as Woit states: "I don’t disagree that to understand cosmology you want to explain the low entropy at the Big Bang.
- If you prefer it, I would say that string theory is the only theory of quantum gravity that has a fundmanetal derivation of the entropy of any black hole.
- The one-loop contribution to the entropy of a black hole from field modes near the horizon is computed in string theory.
- In addition we have calculated correction to the entropy from alpha'^3*R^4 terms coming from string theory.
- The measure should be continuous, so that changing the values of the probabilities by a very small amount should only change the entropy by a small amount.
- Intuitively, entropy quantifies the uncertainty involved when encountering a random variable.
- Entropy is also the shortest average message length, in bits, that can be sent to communicate the true value of the random variable to a recipient.
- That is, we use the entropy of the random variable S in order to save truly random bits later on.
- We can use Lagrange multipliers to find the point of maximum entropy (depending on the probabilities).
- For a given mean and variance, the corresponding normal distribution is the continuous distribution with the maximum entropy.
- Thus, as long suspected, black holes have the maximum entropy for given mass and size which is allowed by quantum theory and general relativity.
- If a system is at equilibrium, by definition no spontaneous processes occur, and therefore the system is at maximum entropy.
- While the random number generator was used to generate 128-bit keys, the maximum entropy was around 20 bits.
- Randomly generated keys aren't necessarily better, because now the random number generator must produce keys with maximum entropy.
- In this case, the entropy increases with the number of outcomes.
- If all the outcomes (letters in the example above) are equally likely then increasing the number of letters should always increase the entropy.
- Such choices may be considered to add information that reduces the entropy (related to number of internal choices) to produce the same external product line.
- The independent components are random variables of minimum entropy constructed from linear combinations of the input features.
- Hamming distance Joint entropy – is the measure how much entropy is contained in a joint system of two random variables.
- Entropy change has often been defined as a change to a more disordered state at a molecular level.
- The fragility of the liquid is, in this case, controlled by the entropy change in the elementary excitation process.
- We can now deduce an important fact about the entropy change during any thermodynamic transformation, not just a cycle.
- The thermodynamic concept of entropy can be described qualitatively as a measure of energy dispersal at a specific temperature.
- Theoretical Physics > Relativity > General Relativity > Black Holes
- Encyclopedia of Finance. > Technology > Energy
- Encyclopedia of Keywords > Nature > Systems > System
- Random Variable
* Black Hole
* Black Holes
* Black Hole Entropy
* Classical Thermodynamics
* Closed System
* Density Matrix
* Equilibrium State
* Fair Coin
* Free Energy
* Hawking Radiation
* Information Content
* Information Entropy
* Information Theory
* Internal Energy
* Long String
* Loop Quantum Gravity
* Net Change
* Pure State
* Radiant Energy
* Second Law
* Statistical Mechanics
* Thermal Energy
* Thermodynamic Entropy
* Thermodynamic Equilibrium
* Zero Entropy
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