Maxwells demon is a thought experiment created by the physicist james clerk maxwell in 1867 in which he suggested how the second law of thermodynamics might hypothetically be violated. Maxwells demon, hypothetical intelligent being or a functionally equivalent device capable of detecting and reacting to the motions of individual molecules. Maxwells demon converts information into energy live science. Over 150 years after the famous scottish scientist james clerk maxwell first introduced the idea, the concept of maxwell s demon continues to perplex physicists and information scientists. Maxwells demon was born in 1867 and still thrives in modern physics. Maxwells demon in biochemical signal transduction with.
Eric lutz is a professor of theoretical physics at the university of erlangen nuremberg in erlangen, germany. Maxwell s demon was first mentioned in a letter written to tait in 1867. Essentially, this law states that heat does not naturally flow from a cool body to a warmer. Maxwellian demons are mechanical devices that carry out measurements on a thermodynamic system, manipulate the system so as to extract work from it, and erase all records of the measurement outcomes. In a rather different context, the recent intensive research on maxwells demona feedback controller that utilizes information of individual moleculeshave led to a unified theory of.
Video also covers reconciling the information theory of entropy. Laplacess demon and maxwells demon, the demons of classical. The demons seductive quality makes it appealing to physical scientists, engineers, computer scientists, biologists, psychologists, and historians and philosophers of science. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and computer scienceand linkages have been established between maxwell s demon and each of these disciplines. Maxwell s 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. In 1871, james clerk maxwell proposed a thought experiment. 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. Over 150 years after the famous scottish scientist james clerk maxwell first introduced the idea, the concept of maxwells demon continues to perplex physicists and information scientists. Connecting the problem of maxwell s demon with that of brownian motion, smoluchowski wrote that in order to. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and computer science and linkages have been established.
He plays important roles in clarifying the connections between two theories. A machine of this type, of great antiquity and fine pedigree, is maxwells demon, the prodigy of james clerk maxwell, one of the biggest brains in nineteenth century science and the architect of the modern classical theory of electricity and magnetism. Since then this being, dubbed maxwell s demon by lord kelvin, has been an active topic of. This second law normally says that heat flows only from hot to cold. 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. Most information theoretic exorcisms of maxwell s demon employ principles that have been derived from the assumption of the second law of thermodynamics, so that the protection of the second law ultimately depends upon assuming its truth. Connecting the problem of maxwells demon with that of brownian motion, smoluchowski wrote that in order to. This thought experiment has provoked debate and theoretical work on the relation between thermodynamics and information theory extending to the. Consider maxwells setup, but with only a single gas particle in a box. Yet it has challenged some of the best scientific minds, and its extensive literature spans thermodynamics, statistical physics, information theory, cybernetics, the limits of computing, biological sciences and the history and philosophy of science. We present an analysis of szilards onemolecule maxwells demon, including a detailed entropy accounting, that suggests a general theory of the entropy cost of information. A physical thought experiment demonstrating how just the possession of information might in principle have thermodynamic consequences was established in 1929 by leo szilard, in a refinement of the famous maxwell s demon scenario consider maxwell s setup, but with only a single gas particle in a box.
As more and more particles accumulate on the same side, the entropy decreases. This problem has led to very interesting links between physics, information theory and the theory of. Maxwell s demon was the invention of scottish mathematician and theoretical physicist james clerk maxwell, who wanted to contradict the second law of thermodynamics although the name was given to. Since then this being, dubbed maxwells demon by lord kelvin, has been an active topic of. Over years ago, james clerk maxwell introduced his hypothetical demon as a challenge to the scope of the second law of thermodynamics. A later tradition sought to exorcise maxwells demon by assessing the entropic cost of the demons processing of information.
It is also shown that there is an entropy symmetry between the. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and computer science, and links have been established between maxwells demon and each of these disciplines. Maxwells demon, hypothetical intelligent being or a functionally equivalent device. In a letter that he wrote in december 1867 to his friend peter guthrie tait, the physicist james clerk maxwell 18311879 described how the action of a being controlling a shutter on a microscopic hole between two gas containers a and b could apparently violate the second law of thermodynamics. Nov 15, 2010 maxwell s demon was the invention of scottish mathematician and theoretical physicist james clerk maxwell, who wanted to contradict the second law of thermodynamics although the name was given to. Here the history of the demon and a variety of interesting consequences of the second law of thermodynamics are presented, mainly in quantum mechanics, but also in the theory of gravity. Exorcism of maxwells demon university of pittsburgh. Entropy, information, computing in 1990, maxwells demon has been the subject of renewed and increased interest by numerous. Maxwells demon is an imaginary creature that the mathematician james clerk maxwell created to contradict the second law of thermodynamics. A little demon sits by a tiny trapdoor in the wall it looks at oncoming gas molecules, and depending on their speeds it opens or closes the trapdoor.
Efforts to exorcise maxwells demon have focused on the information processing a demon supposedly must do. This made scientists crazy for at least a century until information theory came into play. The demon s seductive quality makes it appealing to physical scientists, engineers, computer scientists, biologists, psychologists, and historians and philosophers of science. Maxwell s demon was born in 1867 and still thrives in modern physics. The later area obtained the technical term entropy as a metaphor borrowed from its classical origin in thermodynamics. The concept that a demon opens door to fastmoving particles making them move to one chamber consequently making it hotter than the other chamber is still being widely. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and computer science, and links have been established between maxwell s demon and each of these disciplines. Suppose that you have a box filled with a gas at some temperature. It was imagined by james clerk maxwell in 1871, to illustrate the possibility of violating the second law of thermodynamics. If the demon and thermal system combined are a hamiltonian system, then the intended operation of the demon must compress the overall phase space, in violation of liouvilles theorem. About 120 years ago, james clerk maxwell introduced his now legendary hypothetical demon as a challenge to the integrity of the second law of thermodynamics. Mar 03, 2020 over 150 years after the famous scottish scientist james clerk maxwell first introduced the idea, the concept of maxwell s demon continues to perplex physicists and information scientists.
Most informationtheoretic exorcisms of maxwells demon employ principles that have been derived from the assumption of the second law of thermodynamics, so that the protection of the second law ultimately depends upon assuming its truth. What maxwells demon does is allow heat to flow backwards reverse the arrow of time, if you like by using information about the molecular speed. Jun 23, 2015 in a rather different context, the recent intensive research on maxwells demona feedback controller that utilizes information of individual moleculeshave led to a unified theory of. As the dictionary entry above shows, maxwells demon is no more than a simple idea. Maxwells demon 2 entropy, classical and quantum information. In his 1867 thought experiment, maxwells demon, james clerk maxwell. Maxwells demon is a thought experiment created by the physicist james clerk maxwell in. This means that the average speed of the molecules is a certain amount depending on the temperature. This problem has led to very interesting links between physics, information theory and the theory of computation from concepts of information entropy brillouin, szilard, shannon to reversible computing landauer, bennett.
He realized that the extra work that can be extracted from the demons action has a cost that. One of the most important contributions to this work was the account provided by marian smoluchowski, professor at the jagiellone university in krakow. Here, we present the history of the demon and a variety of interesting consequences of the second law of thermodynamics, mainly in quantum mechanics, but also in the theory of gravity. Information theory is a branch of applied mathematics. Dec 30, 2015 maxwells demon was an instant source of fascination and led to many important results, including the development of a thermodynamic theory of information. Maxwells demon was an instant source of fascination and led to many important results, including the development of a thermodynamic theory of information. But a particularly important insight came in the 1960s from the ibm researcher rolf landauer. By detecting the positions and velocities of gas molecules in two neighboring chambers and using that information to time the opening and closing of a trapdoor that separates them, a tiny, intelligent being could, in theory, sort molecules by velocity. Entropy, information, computing in 1990, maxwell s demon has been the subject of renewed and increased interest by numerous. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and. It is shown that the entropy of the demon increases during the expansion step, due to the decoupling of the molecule from the measurement information.
Maxwells demon demonstration turns information into energy. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and computer. As individual gas molecules approach the door, the demon quickly opens and. Efforts to exorcise maxwell s demon have focused on the information processing a demon supposedly must do. Jul 25, 2018 viewers like you help make pbs thank you. As individual gas molecules approach the door, the demon quickly opens and shuts the door so that only fast molecules are. Maxwell was one amongst a number of researchers in the developing field of thermodynamics who was interested in seeking an understanding of thermal phenomena in terms of an underlying atomic physics. Well, it turns out that living organisms are packed full of maxwell demons. Maxwells demon and the entropy cost of information.
The concept seeks to explain what happens when two objects are subjected to different degrees of heat. Less is more for maxwells demon in quantum heat engines. Fascination with the demon persisted throughout the development of statistical and quantum physics, information theory, and computer scienceand linkages have been established between maxwells demon and each of these disciplines. In his 1867 thought experiment, maxwells demon, james clerk maxwell attempted to show that thermodynamics is not strictly reducible to mechanics. Nov 14, 2010 an image of maxwell s demon extracting energy from the thermal motion of particles in escher s waterfall an artistic paradox in which water flows up a waterfall, instead of down. Maxwells demon was the invention of scottish mathematician and theoretical physicist james clerk maxwell, who wanted to contradict the second law of. The concept of maxwells demon is named after a james clerk maxwell. We may replace the demon by an automatic device with a magic eye which opens the trap door at convenient. If your theory is found to be against the second law of thermodynamics i can. Information theory studies the quantification, storage, and communication of information. Information processing and thermodynamic entropy stanford. The paradox a character who has played an important role in the history of physics, particularly in thermodynamics and information, is maxwells demon. The physics of informationprocessing derived a considerable variety of attempts to understand how maxwells demon could function. Maxwells demon was the invention of scottish mathematician and theoretical physicist james clerk maxwell, who wanted to contradict the.
Concluding chapters explore the associations between information theory, the uncertainty principle, and physical limits of observation, in addition to problems related to computing, organizing information, and inevitable errors. If the supernatural demon knows which half of the box the particle is in equivalent to a. James clerk maxwells idea for violating the second law of thermodynamics. Dec 18, 2018 maxwells demon is smart enough to open the door at the exact time a high energy molecule approaches to let it pass to the other side. It was originally proposed by claude shannon in 1948 to find fundamental limits on signal processing and communication operations such as data compression, in a landmark paper titled a mathematical theory of communication. The most successful exorcism of maxwells demon is smoluchowskis 1912 observation that thermal fluctuations would likely disrupt the operation of any molecularscale demonic machine. A physical thought experiment demonstrating how just the possession of information might in principle have thermodynamic consequences was established in 1929 by leo szilard, in a refinement of the famous maxwells demon scenario. Entropy in thermodynamics and information theory wikipedia. It s 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. If the demon and thermal system combined are a hamiltonian system, then the intended operation of the demon must compress the overall phase space, in violation of liouville s theorem. In the thought experiment, a demon controls a small door between two chambers of gas. The experiment first appeared in an exchange of letters between maxwell and peter tait around 1867.
A discussion of the negentropy principle of information introduces brillouins renowned examination of maxwells demon. It was later unveiled to the public in maxwells book on thermodynamics titled theory of heat, published in 1872. The resolution of the maxwells demon paradox linked thermodynamics with information theory through information erasure principle. Pynchons solution pynchon uses maxwells demon to synthesize the fields of thermodynamics and information theory together into a mysterious unity. Maxwells demon is smart enough to open the door at the exact time a high energy molecule approaches to let it pass to the other side. Shannon and warren weaver, the mathematical theory of communication university of illinois press, urbana, illinois, 1949.
Different demons maxwells device described above is an example of what is called a temperature demon, because it creates a temperature difference that can. Maxwell s demon is a thought experiment created by the physicist james clerk maxwell in 1867 in which he suggested how the second law of thermodynamics might hypothetically be violated. An image of maxwells demon extracting energy from the thermal motion of particles in eschers waterfall an artistic paradox in which water flows up a waterfall, instead of down. 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. Operational derivation of boltzmann distribution with maxwell. Maxwells demon was first mentioned in a letter written to tait in 1867. It was originally proposed by claude shannon in 1948 to find fundamental limits on signal processing and communication operations such as data compression, in a landmark paper. Mar 12, 2018 the concept of maxwells demon is named after a james clerk maxwell. Maxwell s demon is an imaginary creature that the mathematician james clerk maxwell created to contradict the second law of thermodynamics.
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