Irreversibility and heat generation in the computing process. Buy maxwells demon 2 entropy, classical and quantum information, computing on. From quantum computing to m theorythe new physics of information pdf file juvenile nonfiction, an anthology of current thought, 214 pages, fannie huang, an introduction of the field of quantum physics and articles on quantum teleportation, quantum gravity, and quantum computing, 2006, quantum physics, isbn. Measurements convert alternative possibilities of its potential outcomes into the definiteness of the record data describing the actual outcome. The existence of maxwells demon is a direct threat to the second law of thermodynamics. Measurement of the state of a qubit yields 1 classical bit of information. Maxwells demon 2 entropy, classical and quantum information, computing.
Maxwells demon and the thermodynamics of computation je rey bub philosophy department, university of maryland, college park, maryland 20742, usa. T c t h a number less than one, kelvin had to evaluate the ratio of the work output to the heat absorbed during the isothermal expansion with the help of the carnotclapeyron equation, which contained an unknown function called the carnot function. Erasing information is a thermodynamically irreversible process that. Information theory is used in information retrieval, intelligence gathering, gambling, statistics, and even in musical composition. James clerk maxwell opened up the relationship between information and entropy by proposing what is called today maxwells demon, which would apparently violate the second law of thermodynamics. Since the demon and the gas are interacting, we must consider the total entropy of the gas and the demon combined. If we introduce a source of light, the demon can see the molecules, but the over. Maxwells demon in its many forms has captured the imagination of both scientists and the general public. An annotated chronological bibliography provides a colourful perspective on maxwells demon and a rich trail of citations for further study. Dec, 2002 the demon s seductive quality makes it appealing to physical scientists, engineers, computer scientists, biologists, psychologists, and historians and philosophers of science.
Maxwells demon and the thermodynamics of computation je rey bub philosophy department, university of maryland, college park, maryland 20742, usa abstract it is generally accepted, following landauer and bennett, that the process of measurement involves no minimum entropy cost, but the. Entropy and the second law of thermodynamics the second law of thermodynamics in thermochemistry we have seen that reactions are infl uenced by the comparative enthalpies of reactants and products. Entanglement entropy, maxwells demon and quantum error. June 2010 contents 1 introduction 1 2 entropy in thermodynamics 2 3 information theory 4 4 statistical mechanics 9 5 dynamical systems theory 18 6 fractal geometry 26 7 conclusion 30 1 introduction entropy is ubiquitous in physics, and it plays important roles in numerous. Daemons in computing, generally processes that run on servers to respond to. In the field of cryptology, there are formal proofs that show that if an adversary can correctly distinguish an encrypted file from a file that is truly random with a greater. Entropy is technically defined here and is the second law of thermodynamics. Pdf maxwells demon and the second law of thermodynamics. Maxwells demon can use quantum information to generate work.
The thermal entropy due to the molecules moving faster or slower is a red herring and actually isnt important for understanding maxwells demon at all. Simply put, entropy as it relates to digital information is the measurement of randomness in a given set of values data. Maxwells demon is a character in an 1867 thought experiment by the scottish physicist james clerk maxwell, meant to raise questions about the second law of thermodynamics. Discarding it leads to immediate increase in entropy but the demon cannot store. The computer in the bathtub includes many relevant parameters, such as heat, entropy, and information. The demon really has something for everyone, and that helps make it a very powerful teaching tool. The field of information thermodynamics traces its origins to a. Here we realize a maxwells demon acting on a superconducting quantum circuit. Apr 12, 20 file entropy is also use in the field of malware protection, in the process of malware analysis as there are all kind of security related tools that you check on the file to extract all kind of information from the file, to determine if the file is a malware or legit file, and if it is a malware this can be useful on the malware file entropy. Entropy, classical and quantum information, computing retains many of the seminal papers that appeared in the first edition, including the original thoughts of james clerk maxwell and william thomson. As the dictionary entry above shows, maxwells demon is no more than a simple idea. Now it is appropriate to return to the roots of the problem.
Dec 18, 20 in theory, maxwells demon can decrease the entropy of a system by opening and closing a door at appropriate times to separate hot and cold gas molecules. Since then this being, dubbed maxwells demon by lord kelvin, has been an active topic of. A maxwells demon is a device that gets information and trades it in. Entropy, information, computing in 1990, maxwells demon has been the subject of renewed and increased interest by numerous. Algorithmic information content, church turing thesis. Different demons maxwells device described above is an example of what is called a temperature demon, because it creates a temperature difference that can be used to run a heat engine. Maxwells demon 2 entropy, classical and quantum information. Entropy, information, computing makes the key literature easily available and helps with the crossfertilisation of ideas in different disciplines. The possibility that the carnot function could be the temperature as measured from a zero. The important entropy here is the mixing entropy that has to do with how wellsorted these different kinds of molecules are. The technical explanation of entropy in computing terms is described here. To set or reset the apparatus into this state will cost all the entropy that can be saved by knowing the state of szilards particle. Traverse through the file and for each of its bytes, increment the corresponding position in the array. The thermodynamic meaning of negative entropy nature.
The main thesis of the paper is that state collapse during a measurement and hence entropy increase in the observed universe is seen by observers who are only able to observe a restricted manifold of states determined by their concepts. The paradox a character who has played an important role in the history of physics, particularly in thermodynamics and information, is maxwells demon. B board the band theory of solids is arguably the most successful theory of. Entropy, information, computing princeton series in physics 45 on. Mar 29, 2018 maxwells demon is a hypothetical character that uses information about a system to reduce its entropy. May, 20 therefore, the more entropy in the data file, the less it can be compressed. After more than 120 years of uncertain life and at least two pronouncements of death, this fanciful character seems more vibrant than ever. Entropy a guide for the perplexed roman frigg and charlotte werndl.
File entropy explained computer forensics, malware analysis. Energy 0 2 1 4 3 ground state 0gv excited state 1e energy levels of a quantum system are discrete. Entropy, eissn 10994300, published by mdpi ag disclaimer the statements, opinions and data contained in the journal entropy are solely those of the individual authors and contributors and not of the publisher and the editors. Maxwells demon in 1867 james clerk maxwell suggested that a sentient being capable of observing molecular motions might be able to bring about a violation of the second law of thermodynamics through a systematic sorting of molecules. Brillouin science and information theory pdf files. Entropy, classical and quantum information, computing retains many of the seminal papers that. This law forbids among other things two bodies of equal temperature, brought in contact with each other and isolated from the rest of the universe, from evolving to a state in which one of the two has a significantly.
This book is a survey of about a century and a half of thought about maxwells demon with significant focus on landauers principle and the work surrounding it. We present some new results on the nonparametric estimation of entropy and mutual information. Hence, he cannot operate the trap door and is unable to violate the second principle. A quantummechanical maxwells demon seth lloyd darbeloff. Its a thought experiment which demonstrates that the concept of entropy from information theory and the concept of entropy from thermodynamics are really about the same thing, and connected in a very physical way. Entropy quantifies the amount of uncertainty involved in the value of a random variable or the outcome of a random process. Informationtowork conversion by maxwells demon in a. Landauer and bennett, in which maxwells demon is related to the idea of dissipationless computing. The problem of the subjective nature of entropy and its relation to information and irreversibility is examined in the light of the quantum measurement problem. Entropy, information, computing in 1990, maxwells demon has been the subject of renewed and increased interest by numerous researchers in the fields mentioned above. Maxwell, 1911 to discuss the limitations of the second law of thermodynamics. Or lets just say a bunch of bytes i have an idea, but im not sure that its mathematically correct.
Motion machines of second kind scientific research publishing. Entropy, classical and quantum information, computing find, read and cite all the research you need on researchgate. In this paper, we will underline the flaw that exists in maxwells demon paradox using chemical. The resulting decrease of statistical entropy has been, since the inception of maxwells demon, regarded as a threat to the second law of thermodynamics. About 120 years ago, james clerk maxwell introduced his now legendary hypo. Maxwells demon is a thought experiment created by the physicist james clerk maxwell in. This file contains supplementary text and data 15, supplementary. Entropy, information and maxwells demon after quantum. Szilard pointed out that a reallife maxwells demon would need to have some means of measuring molecular speed, and that the act of acquiring information would require an expenditure of energy. Maxwells demon and the thermodynamics of computation.
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