Physicists from Finland, Russia and the United States pioneered Maxwell's autonomous electronic demon. The authors published the results of their research in the journal Physical Review Letters. What are Maxwell's demons and how they can interfere with computers, says "Lenta.ru".
The intrigue around Maxwell's demons has been preserved in science for 150 years. The concept of a supernatural being was proposed in 1867 by the British physicist James Clerk Maxwell. We are talking about a certain device that functions in such a way that it leads to a violation (apparent) of the second law of thermodynamics - one of the most fundamental laws of nature.
In his thought experiment, Maxwell took a closed gas cylinder and divided it into two parts by an inner wall with a small hatch. By opening and closing the hatch, Maxwell's demon separates the fast (hot) and slow (cold) particles. As a result, a temperature difference appears in the cylinder, and heat is transferred from a colder gas to a hotter one, which would seem to contradict the second law of thermodynamics.
The second law of thermodynamics determines the direction of physical processes. In particular, as the German physicist Rudolf Clausius showed, he makes it impossible for spontaneous transfer (that is, without doing work) heat from a colder body to a hotter one, or, which is the same, a decrease in the entropy (measure of disorder) of an isolated system. In the formulation of the Frenchman Sadi Carnot, this law sounds like this: a heat engine with a coefficient useful action one hundred percent impossible.
The second law of thermodynamics was finally formulated in the 19th century. Then it was the law for a number of special cases (its fundamental nature became clear later). Physicists were looking for contradictions in it, and one of them (along with the heat death of the Universe) was presented by Maxwell in a letter to his colleague Peter Tate.
The paradox immediately attracted the attention of scientists and science enthusiasts. In the 20th century, the glory of the demon Maxwell was eclipsed by Schrödinger's cat (or cat). Meanwhile, like a pet from quantum mechanics, the British physicist's imp was the source of many important discoveries. In particular, thanks to him, the thermodynamic theory of information and the related concept of information entropy arose.
In the 1960s, Rolf Landauer, a researcher at the American company IBM (International Business Machines), formulated the principle that was given his name. He linked the loss of a bit of information in any physical system with the release of a corresponding amount of heat (or, which is the same, an increase in thermodynamic entropy). Landauer's work was fundamental to computing technologywhich has been preserved to this day. The expression named after Landauer, as well as the Americans Claude Shannon and John von Neumann, makes it possible to determine the limiting physical characteristics of the device (first of all, its power and size) at which information is destroyed. Man-made processors have gone from dissipating heat, billions of times greater than that predicted by Landauer's principle, to modern values \u200b\u200bjust a thousand times greater.
Let there be a memory cell containing information encoded in bits (with values \u200b\u200bzero and one). If you destroy it (that is, put it in a state containing only zeros or ones), heat will be released. In the language of thermodynamics, this means that the entropy of the system vanishes, since the most ordered state has been reached (described only by zeros or ones). Landaeuer liked to repeat that “information is physical quantity”, That was his motto.
For the first time, scientists from France and Germany measured the heat released when a bit of information is destroyed. The memory cell was a quartz bead with a diameter of two micrometers, placed in water. Using optical tweezers, physicists created a pair of potential holes in which the bead could end up. These states of the system corresponded to the logical values \u200b\u200bzero and one. When the system was put into one state, the information was erased. The machine took into account many nuances, in particular, fluctuations, whose role grew along with a decrease in the depth of the pits. With the help of rapid, physicists observed the transition of a system from one state to another. The process was accompanied by heat release, the water temperature increased, and this was recorded. The data obtained turned out to be close to those predicted by the Landauer principle.
But what does Maxwell's demon have to do with it? The fact is that when sorting hot and cold molecules in Maxwell's thought experiment, the demon accumulates information about the particle velocities. At some point, the memory becomes full, and the demon needs to erase it to continue working. This requires work to be done, exactly equal work, which could theoretically be extracted from a system of hot and cold particles. That is, the second law of thermodynamics is not violated. However, a metaphysical question arises about the entity that erases the demon's memory. Would it be some kind of super demon influencing the younger demon? The answer to this question was first proposed in 1929 by one of the participants in the Manhattan Project american physicist Leo Szilard. The device named after him provides autonomous work for Maxwell's demon.
For the first time, Japanese scientists managed to implement it in 2010. Their electromechanical model is a polystyrene bead about 300 nanometers in diameter, placed in an electrolyte. The electromagnetic field prevented the bead from moving downward, as a result of which it gained mechanical (potential) energy proportional to the work of the field. The Demon of Maxwell in such a system was the observer and his scientific instruments, which require energy to function. The latter circumstance again does not allow violating the second law of thermodynamics. Unlike Japanese scientists, their colleagues from Finland, Russia (Ivan Khaimovich from the Institute of Physics of Microstructures Russian academy Sciences) and the United States for the first time created not an electromechanical, but a completely electronic machine of Szilard (Maxwell's autonomous demon).
The system is based on a single-electron transistor that forms a small copper island connected to two superconducting aluminum leads. Maxwell's demon controls the movement of electrons of different energies in the transistor. When a particle is on an island, the demon attracts it with a positive charge. If an electron leaves the island, the demon pushes it away with a negative charge, which leads to a decrease in the transistor temperature and its increase in the demon.
The demon performs all manipulations autonomously (its behavior is determined by the transistor), and temperature changes indicate a correlation between it and the system, so everything looks as if Maxwell's demon knows about the state of the system and is able to control it. The electronic daemon allows a large number of measurements to be carried out in a short period of time, and low temperatures in the system make it possible to register extremely small changes in it. This system also does not violate the second law of thermodynamics and is consistent with the intuitive notion that information can be used to get work done.
Why do scientists need such research? On the one hand, they are of clear academic interest, since they allow studying microscopic phenomena in thermodynamics. On the other hand, they show how important it is to produce entropy from the information received by the demon. It is this, as the authors of the study believe, useful for designing qubits (quantum analogs of classical bits) of quantum computers, even despite the emerging progress in reversible computing, the story of which is beyond the scope of this article.
Maxwell's Demon, quantum demon
James Maxwell's delusional idea, when he invented the power to turn back time in 1867, described the awareness of a "demon" who could override the law of entropy by tracing the smallest movements of gas molecules. In this way, the demon was able, at least in Maxwell's fantasy, to reverse the increase in confusion in closed systems.
Learn more about demon awareness
Maxwell's imaginary demon was in a closed box and was reversing the flow of molecules, recreating a degrading order. Below you can see a smiling face that depicts this demon.
(Caption under the picture: Demon in a box with molecules)
The demon, the prototype of consciousness in matter, notices what is happening and controls it, making special choices. It keeps hot material on one side of the box and colder material on the other so that the original "order" (hot and cold) does not degrade. The demon arranges everything so that in a closed system, energy should not become less available, or information should not be lost. By using awareness to open and close the partition that separates the two volumes of gas in the container, the demon reverses the second law of thermodynamics. Until now, no one has been able to find such a demon or create it in the generally accepted reality.
Yet Maxwell's fantasy may be more true than he himself realized. It seems to me that he could project our ability to be aware, our ability to notice "nanoscopic" events or flirting. This almost immeasurable quantum awareness is the ability of awareness that can make choices in the dreamland.
Maxwell's demon is, in fact, a potential hero of psychotherapy, for it is the part of us that restores order by seeing patterns where the previous patterns have been lost (forgotten, repressed, ignored, marginalized, etc.). In my opinion, the second law of thermodynamics is a projection of a typical lifestyle in accepted reality that uses a minimum of awareness. Maxwell's Demon is a representation of our lucid awareness operating at non-measurable subatomic levels of nano-events, and capable of at least alleviating the sensation of aging.
The psychological principle projected on Maxwell's demon is:
Seeing an order hidden in a mess of accepted reality creates more energy available.
Ignoring or even suppressing subtle symptom signals is depressing and devastating. Recognizing symptoms as “calls” for attention allows you to create order out of clutter and generally gives you more energy to work. The marginalization of experience makes you feel like a decaying universe.
I call Maxwell's demon a kind of “quantum demon of awareness,” a clear ray of consciousness that traces the movements of atoms and molecules, as well as subatomic events. During Maxwell's lifetime, quantum mechanics had not yet been invented. He did not yet know about wave functions; they were to appear fifty years later. But if he lived today, he would certainly be interested in the kind of awareness that can detect and track subtle trends, the quantum waves of the dreamland, and the guidance they give us. As I imagine, he would say that ignoring all the subtle feelings that flicker in our awareness creates devastation and makes us feel older than we really are.
The next exercise gives you a chance to discover and experience the demon's ability to increase the amount of physical energy available to you. We will especially focus on the “closed” areas of your life.
Exercise in awareness of negentropy
1. Sit back and think about how you feel about aging. What do you like about him? What's not to like?
For example, many people enjoy the opportunity to fulfill their potential, but dislike the loss of energy and what they call "attraction." Some people think that life is coming to an end.
2. When you're ready, look around for something to pick up or push. If you are standing in a room, lift a chair or push off one of the walls and see how much energy you have available. As you lift or push, ask yourself: "What part of my energy is available to me now?" Write down this amount of energy. How much is 85%, 50% or 15%? How old do you feel?
For example, when I lifted a chair today, it felt heavier than it should be. I would say that about 50% of my energy is available to me.
3. The amount of available or isometric energy that you have depends very much on your sense of order within yourself. So now think about one area of \u200b\u200byour life that seems "disordered." If possible, choose a new area, not relationships or bodily symptoms, as we have worked on these before.
For example, you may find your job, your finances, or, say, a dump on your desk or how you use your time seem to be disordered. Perhaps your attitude towards criticism is “confused”.
Don't overlook ignored areas of your life in need of order. If there are many such areas, choose only one for now - any will do. How do you manage to avoid this area? In what sense is this area “closed”? Are you avoiding or “forgetting” about questions related to this area? How do you forget about these questions? Are you trying to sleep more or are you just complaining about them? Are you getting them out of your head? Do you watch TV or go to the movies instead of cleaning up the area?
4. Now, thinking about this disordered area, imagine what kind of "space" it is in. What colors and movements are taking place in this space? Describe in your own words the characteristics of the space that contains this disordered area of \u200b\u200blife.
For example, does it look gray or cloudy? Spinning and stirring?
Can you identify some place outside your body where this "disordered area" could be, where this space would be located? (for example, in front of you, behind you, etc.). Draw this unordered area next to your body.
(Legends in the picture, from top to bottom: In finance, complete chaos, big storm clouds, oh my poor head! The disordered area affects the head)
In the illustration, the disordered area is related to finance and appears to be overhead.
How does the part of your body that is closest to this space feel? Do you have any bodily symptoms near this area? Choose a bodily symptom to work with, or one of the symptoms, say the one you paid the least attention to. Is this symptom related to your feeling of aging?
5. Focus on the symptom in this area of \u200b\u200bthe body and identify two aspects of it. For example, see if you can form an image of the energy that you suspect or imagine is causing this symptom, and then do the same for the receiver of that energy or action. In other words, imagine, so to speak, a "symptom maker" and a "symptom recipient."
One way to imagine these two figures is to get a feel for a symptom, or imagine that you will feel it. Then, exaggerate that feeling by increasing its intensity. Using your attention, stay with this feeling until a figure arises that could embody that intensity.
For example, if you had a knocking headache, you could emphasize the sensation of this knock until there is an angry figure pounding on the table and a sensitive figure (say, the table itself) that is hurt by the knock.
Try to recognize the message that each figure expresses.
For example, an angry figure might say, "I have to punch my way through things," while another says, "Please don't do that, it's too rude and hurts me!"
6. Imagine these two figures, one suffering and the other creating a symptom. Even draw them. Then allow your imagination to spontaneously create a being whose awareness comes to the scene and resolves the conflict between these two energies. For example, imagine a skilled mediator, genie, spirit, cartoon character - someone who can deal with both energies. Describe it. Draw it.
For example, one of my readers had a conflict between her worldly ambition and the part of her that was weighed down by this ambition. To her surprise, she saw a priest who helped her resolve the conflict between these two energies. Below I have tried to draw all three shapes.
The priest blessed both parts of it, and they relented.
(Captions under the figures, from left to right: Part that weighed down; Spirit-helper; Ambitious part)
At some point, you might try to become your helper spirit, your demon of quantum awareness. Enter the psychologically closed system of your dreaming body and intervene; facilitate the resolution of the conflict between the two parts in this symptom area.
Imagine the resulting story. Let the quantum demon magically intervene and find a solution.
A reader whose symptoms parts were lacking in the God represented by the priest. At first, the reader was embarrassed to identify with the priest, until she realized that, in a sense, she had already devoted her life to the "divine."
7. Use your breathing to focus on the feeling of this conflict resolution and, if possible, feel a sense of relief in the symptom area.
8. Imagine how this solution could be used in the disordered area of \u200b\u200blife with which you started this exercise. Think back to the original mess - its space, colors, and movement - and note (or better yet, draw) how this area transformed. Don't "work" on it, just let everything happen on the inside until things change for the better.
9. Finally, return to the wall or chair and, being careful, look again at what effect this work may have had on your sense of the energy available to do what you need in life. What changes in your available energy do you notice?
From the book Hyperborean doctrine author Tatishchev B Yu3.3. Demon DEGENERATION. What are these "degeneration mechanisms"? For the answer, first, let's turn to a talented and honest book former leader No. 2 of the political movement of "Western" Zionism, a student of the professor-psychiatrist Cesare Lombroso, Dr. Max
From the book Teaching of the Temple. Instructions of the Teacher of the White Brotherhood. Part 2 author Samokhina N.The DEMON of Avarice The wanderer with a great soul stopped on his way through the desert of fleeting life, when he saw a kneeling woman, prayerfully folded her hands on her chest, gazing at him, from whose lips pleading for forgiveness and forgiveness of sin broke. Listening
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From the book Quantum Magic the author Doronin Sergei Ivanovich4.1. Quantum processor
author Gardiner PhilipQuantum world I am inspired by the thought that in the Universe (from micro to macro level, from the cosmic movement of planets to the interaction of electrons, from microscopic silicon dioxide to man-made egyptian pyramid) a universal model is laid, not
From the book Gateway to Other Worlds author Gardiner PhilipQuantum God While working on this book, I allowed myself one day's rest from quantum physics and drove to Lichfield, Staffordshire. I had a great time in the beautiful, esoteric feeling of Lichfield Cathedral, gazing at its amazing façade
From the book XX century. Chronicle of the inexplicable. Phenomenon after phenomenon author Priyma AlexeyDEMON JUMPED OUT OF THE MOUTH Now let's move on to another stunning story. It happened with a psychic and clairvoyant Tatyana Makhotina. I have known Tatyana for a long time, she is a very honest person, and because of this I vouch for the reliability of her story. In July 1995, Makhotin From the book Geopsychology in Shamanism, Physics and Taoism the author Mindell Arnold
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From the book of the End of the World there was not and will not be the author Gusev Anatoly IvanovichBony Demon In 1999, a group of English paleontologists worked in the area of \u200b\u200bUulakh in the Mongolian Gobi Desert. Their goal was to explore a dinosaur cemetery in a remote mountain gorge. From local residents scientists had a chance to hear the legend about living in the gorge
the author author unknownAn entertaining story about how a demon named Rush came to the monastery to be hired for service There was a monastery in one overseas country. He stood at the edge of a large forest, so that the holy brothers would not be distracted from serving the Almighty and prayed him day and night for the founders and
From the book The Brother Rush Story the author author unknownAbout how a demon named Rush came to the house of a noble lady and secretly brought her to his master - Hello to you, beautiful kind lady, the most beautiful of all living. My host sends you his greetings and asks you to come and talk to him.
From the book Secrets of the Brain. Why do we believe in everything author Shermer MichaelHow can you get energy from information? Until recently, only a demon was capable of this - a fantastic creature invented in 1867 by the great physicist James Maxwell to illustrate the paradox of the second law of thermodynamics. Now Japanese scientists are close to developing such an experimental model. In the future, they hope to create nanomachines that feed on information. The work of scientists is published Nature physics.
the demon "is able to follow the trajectory of each molecule and perform actions completely inaccessible to us."
In other words, the demon is capable of distinguishing and sorting individual molecules. How to extract energy from this ability? Imagine a certain vessel divided into two parts by a partition (in the picture). The vessel is filled with molecules of two types: “hot” (dark in the figure) particles move faster, and “cold” (light ones in the figure) move more slowly. In a state of equilibrium (upper part of the figure), the molecules are mixed, as required by the second law of thermodynamics: any system in an isolated state tends to the maximum entropy, that is, the maximum disorder.
Illustration of the work of "Maxwell's demon" // nanometr.ru
However, there is a hole in the partition that the same demon can open and close. It possesses the ability described above, that is, it distinguishes "hot" particles from "cold" ones. Therefore, he can “work” so that all the “hot” particles are to the right of the partition, and the “cold” ones to the left. To do this, he will allow Brownian (randomly) moving "hot" particles from the left side to overcome the partition, but not from the right (and do the opposite with the "cold" particles). As a result, an ordered state will arise from a disordered state, which contradicts the second law of thermodynamics. Maxwell's demon, using only information about the quality of the particles, will create energy due to the temperature difference in the two parts of the vessel, which can then be used.
In this way,
initially it seemed that the demon receives energy "from nothing" and creates a perpetual motion machine.
However, the paradox was resolved, because the demon himself must spend a certain energy in order to obtain information about chaotically moving particles. Therefore, there is no violation of the laws of thermodynamics: energy arises from the work done by the demon.
One way or another, no one was able to create a physical working model of the demon and show how it works.
Japanese scientists, however, reported in the latest issue of Nature Physics the success of such an experiment. They created a miniature "demon" using a polymer ball and an electric field.
In the experiment, we used two balls made of polystyrene, ordinary plastic, with a diameter of 0.3 μm (300 nm). One of them was fixed on a glass surface, and the second was located so that it could rotate freely around the first. The entire system was immersed in liquid. As a result of the chaotic motion of liquid molecules, the system rotated with equal frequency both clockwise and counterclockwise (due to its small size, the ball successfully “felt” fluid fluctuations).
Then an additional electric field was applied to the liquid, which imparted a rotational moment to the system of balls. The rotation pattern of the system has been preserved. Although in some cases the energy of the chaotic motion of liquid particles was sufficient to turn the ball against the direction of the electric field, nevertheless, more often the system followed the rotational moment imparted to it by the field.
the “demon” itself appeared on the “stage” in the form of a camera and a computer controlling the electric field.
The camera controlled the rotation of the system; as soon as the system was able to independently resist the applied electric field, the "demon" in the computer changed its mode, slightly "pushing" the system in the desired direction. Then she again followed him herself, using only the forces of Brownian motion.
Thus, the rotating system produced mechanical energy... Calculations have shown that the energy produced is slightly greater than the energy of the electric field applied to the system. The "demon" only needed information about the direction of rotation of the system in order to create it. It turned out that at room temperature, one bit of information is capable of creating a very small energy of 3x10 -21 joules.
“We have shown the ratio of information and energy obtained when the“ demon ”works, and confirmed the fundamental principle of its work,” said one of the authors of the work, Shoichi Toyabe, quoted by NewScientist.
He stressed that the energy produced by the system is negligible, but in the future it can be used to power nanodevices.
"Maxwell's Demon" is a thought experiment invented by James Maxwell in 1867 to illustrate the seeming paradox of the Second Law of Thermodynamics. The main character of this experiment is a hypothetical intelligent microscopic creature, later named "Maxwell's demon".
Suppose that a vessel with gas is divided by an impermeable partition into right and left parts. There is a hole in the partition with a device, the so-called Maxwell's demon, which allows fast, hot gas molecules to fly only from the left side of the vessel to the right, and slow, cold molecules only from the right side of the vessel to the left.
Then, after some rather long period of time, all hot molecules will be on the right, and cold ones - on the left. Thus, it turns out that the demon of Maxwell, without additional energy supply, can heat one part of the vessel and cool another.
As a result, it turns out that the entropy of a system consisting of two halves is greater in the initial state than in the final state, and this contradicts the thermodynamic principle of non-decreasing entropy in closed systems, i.e. the second law of thermodynamics.
Indeed, it follows from the second law of thermodynamics that it is impossible to transfer heat from a body with a lower temperature to a body with a higher temperature without performing work.
The paradox is resolved if we consider a closed system that includes the demon Maxwell and the vessel. For the functioning of the demon Maxwell itself, it is necessary to transfer energy to him from an external source. Due to this energy, the separation of hot and cold molecules would be produced.
Such a memorable bas-relief appeared in honor of James Maxwell and his elusive demon on the wall of one of the US universities.
And if such a demon could exist in reality, then it would be possible to create a heat engine that would work without consuming energy.
With the development of information theory, it was found that the measurement process may not lead to an increase in entropy, provided that it is thermodynamically reversible.
However, in this case, the demon must memorize the speed measurements (deleting them from the demon's memory makes the process irreversible).
Since memory is finite, at a certain moment the demon is forced to erase the old results, which ultimately leads to an increase in the entropy of the entire system as a whole.
In 2010, physicists from the University of Tokyo managed to implement the thought experiment in reality. Scientists noted that they were inspired to create this experiment by the famous demon Maxwell. For the first time, Japanese physicists have succeeded in converting information into energy.
They have created a working nanoscale system that converts information into energy with an efficiency of about 28 percent (for comparison, the efficiency of the most modern internal combustion engines is slightly over 40 percent). Scientists do not exclude that in the future the principle they have developed will make it possible to create systems in which the dimensions of both the controlled object and the “demon” will not exceed hundreds of nanometers.
And in 2015, physicists from Finland, Russia and the United States created an autonomous artificial Maxwell demon, which was implemented in the form of a single-electron transistor with superconducting aluminum leads. Maxwell's demon controls the movement of electrons through the transistor.
The installation will help to study microscopic phenomena in thermodynamics and can find application in qubits for quantum computers.
Is it possible to violate the second law of thermodynamics?
In science, as in fiction, there are fantastic characters. Perhaps most of them were invented during the discussion of the second law of thermodynamics. The most popular of these was the Maxwell demon, which was invented by James Clerk Maxwell, the author of the famous Maxwell system of equations that completely describes electromagnetic fields. The second principle (or law) of thermodynamics has many formulations, the physical meaning of which, however, is identical: an isolated system cannot spontaneously pass from a less ordered state to a more ordered one. So, a gas consisting of molecules moving at different speeds cannot spontaneously split into two parts, in one of which molecules will gather, moving, on average, faster than the average speed, and in the other, slower.
Many physical processes fall into the category reversible. Water, for example, can be frozen, and the resulting ice can be melted again, and we get water in the same volume and condition; iron can be magnetized and then demagnetized, etc. In this case, the entropy (degree of order) of the system at the initial and final points of the process remains unchanged. There are also processes that are irreversible in the thermodynamic understanding - combustion, chemical reactions and so on. That is, according to the second law of thermodynamics, any process ultimately leads either to preservation or to a decrease in the degree of ordering of the system. This disharmonious situation greatly puzzled physicists of the second half of XIX centuries, and then Maxwell proposed a paradoxical solution that would seemingly bypass the second law of thermodynamics and reverse the steady growth of chaos in a closed system. He proposed the following "thought experiment": Imagine a sealed container, divided in two by a gas-tight partition, which has a single door the size of an atom of gas. At the beginning of the experiment, the upper part of the container contains gas, and the lower part contains full vacuum.
Now let's imagine that a certain microscopic watchman is attached to the door, vigilantly watching the molecules. He opens the door for fast molecules and passes them through the partition, into the lower half of the container, and leaves the slow ones in the upper half. It is clear that if such a mini-watchman is on duty at the door long enough, the gas will split into two halves: in the upper part there will be cold gas, consisting of slow molecules, and in the lower part, hot gas from fast molecules will accumulate. Thus, the system will be ordered in comparison with the initial state, and the second law of thermodynamics will be violated. Moreover, the temperature difference can be used to obtain work ( cm. The cycle and Carnot's theorem). If such a watchman is left on duty forever (or organized shift duty), we will get a perpetual motion machine.
This funny watchman, who was nicknamed "Maxwell's demon" by his witty colleagues, still lives in scientific folklore and excites the minds of scientists. Indeed, a perpetual motion machine would not harm humanity, but here's the problem: apparently, in order for Maxwell's demon to work, he himself will need energy supply in the form of an influx of photons necessary to illuminate the approaching molecules and sift them. In addition, sifting molecules, the demon and the door cannot but interact with them, as a result of which they themselves will steadily receive thermal energy from them and increase their entropy, as a result of which the total entropy of the system will still not decrease. That is, with such an explanation, the theoretical threat to the second law of thermodynamics was assigned, but not unconditionally.
The first truly compelling counterargument came shortly after the birth of quantum mechanics. To sort the flying molecules, the demon needs to measure their speed, but he cannot do this with sufficient accuracy due to the Heisenberg uncertainty principle. In addition, due to the same principle, he cannot accurately determine the location of a molecule in space, and some of the molecules in front of which he opens a microscopic door will miss this door. In other words, Maxwell's demon turns out to be a macroscopic elephant in the china shop of the microcosm, which lives by its own laws. Bring the demon in accordance with the laws of quantum mechanics, and he will be unable to sort gas molecules and simply cease to pose any threat to the second law of thermodynamics.
Another compelling argument against the existence of a watchman demon appeared in the computer age. Suppose Maxwell's demon is a computer automated door opening control system. The system performs bitwise processing of the incoming information about the velocity and coordinates of the approaching molecules. Having passed or rejected a molecule, the system must reset the previously ordered information - and this is tantamount to an increase in entropy by an amount equal to the decrease in entropy as a result of gas ordering when a molecule passes or rejects, information about which has been erased from the RAM of the computer daemon. The computer itself, moreover, is also heated, so that in such a model in a closed system consisting of a gas chamber and an automated throughput system, the entropy does not decrease, and the second law of thermodynamics is fulfilled.
Sorry for the demon - he was a cute character.
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An amazingly helpless explanation for the impossibility of the Demon Maxwell!
The argument is about the quantum uncertainty of the world! Consequently, the author has no arguments against the impossibility of the existence of a demon in a model thermodynamic world, consisting only of mechanical particles. After all, if the world consists of mechanical particles, it makes no sense to say that the demon will "heat up", that he needs to "illuminate" the particles in order to determine whether to open the partition, etc.
The simple notion that the mechanical demon does not need to light or otherwise interact with the particles did not occur to the professor. The demon can, knowing the initial impulses and coordinates of all the particles in the vessel, simply calculate the moments when a fast particle flies up to the partition and open it. Moreover, no heating occurs during elastic collisions, and accordingly, the entropy of the demon does not increase.
In general, the root of the difficulties of the professor and all modern physics - unclear ideas about entropy. Physicists insist that this is an objective category, while its definition includes the subjective concept of "disorder", "measure of disorder". There is no objective measure of disorder.
To answer
\u003e A startling explanation for its helplessness ... the argument about the quantum uncertainty of the world is involved!
The explanation may be helpless in your opinion, but that does not change the fact that it is correct. The impossibility of the Maxwell demon is directly related to quantum uncertainty.
\u003e The demon can, knowing the initial impulses and coordinates of all particles in the vessel, simply calculate the moments when a fast particle flies up to the partition and open it.
The demon cannot know anything like that. And the main reason for this is precisely quantum uncertainty. But even without it, in a purely mechanical world, accurate prediction of the trajectories of molecular motion turns out to be impossible due to the effect of exponential divergence of trajectories, which is studied in the theory of mathematical billiards. An arbitrarily small error in the knowledge of the initial positions in a short time exceeds any given value.
There is one more reason. In order for the demon to track all the positions of the molecules, he must have sufficient memory and be able to change its contents as a result of the impact on the molecules. Memory is a physical device and has entropy. Calculations show that the entropy that accumulates in this memory just compensates (or exceeds) its decrease in the gas. (All calculations were cited in one of the articles of the journal "In the world of science" back in the 1980s, but I cannot give a link now.)
\u003e In general, the root of the difficulties of the professor and of all modern physics is unclear ideas about entropy.
Entropy is indeed a difficult concept, but in this matter, everything is clear with it.
\u003e Physicists insist that this is an objective category, while its definition includes the subjective concept of "disorder", "measure of disorder".
You are wrong. The concept of "disorder" is not included in the definition of entropy. It is used only for a popular, and, therefore, figurative and inaccurate explanation of this concept. Formal definitions of entropy (by the way, there are many of them) do not contain anything like this. For example, here are the two most common definitions and physics:
Entropy is a quantity proportional to the logarithm of the number of microstates realizing one macrostate in which the system under study is located (S \u003d k * ln (W)).
The increase in entropy is the energy received by the system, referred to the temperature of the system (dS \u003d qQ / T).
You can read more about this, for example, here: http://www.cultinfo.ru/fulltext/1/001/008/126/734.htm. In this rather large encyclopedic article about the "measure of disorder" is mentioned only once, and that one as an explanation to the equation S \u003d k * ln (W).
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\u003e\u003e The impossibility of the Maxwell demon is directly related to quantum uncertainty .... The demon cannot know anything like that. And the main reason here is precisely quantum uncertainty ... In order for a demon to track all the positions of molecules, he must have sufficient memory and be able to change its contents as a result of influencing the molecules. Memory is a physical device and has entropy.
HaHa. HaHaHA. The demon also needs handles and legs to open and close this door. And you need to eat ... Is this riddle still being solved with such vulgar excuses using smart words such as entropy, quantum uncertainty ... the memory of the demon (!!!) It's funny by God.
There is no demon. Imagine a room filled with bouncing balls - perfectly elastic and not subject to friction (a permissible mechanical analogy of gas molecules). On one side, there is an opening in the room, enclosed by a barrier of some height. Balls jumping above this barrier will eventually fly from the room to the next room, and in the first only balls sluggishly jumping will remain. Does a barrier need memory or energy, photons, muons, bosons or synchrophasotorons? Does he need to calculate any enropy or attract astral forces? In order to immediately suppress the inclinations on the topic "from the next room the fast balls will return back", we will make a funnel in the second room through which the balls fly into the third room, and it is difficult for them to fly back.
In electronics, the barrier effect (electrons with energies above a certain value without loss (!) Pass the barrier, those that do not - do not pass, but they do not lose energy either) has long been known and is being used with might and main. Look on Google - for general development.
The "paradox" of these balls and, accordingly, Maxwellian vessels can be solved very simply - the very fact of sorting the balls is not work. Work is using (taking away) the energy of fast balls. And once we use (take away) the energy from the ball, we turn it into a slow one - which will not jump over the barrier. To continue the cycle, you need fresh balls from the outside.
\u003e\u003e With that said, I recommend when discussing scientific issues... trust your fantasies a little less.
And I would recommend you not to refer to stupid superstitions just because smart and fashionable words appear there ...To answer
In general, there are no completely closed systems in nature; this is an abstraction for deriving thermodynamic formulas. And in our reasoning, we don't even notice how we inadvertently move to open systems. And in open systems, entropy must be treated as follows from the work of Ilya Prigogine. But that's not the point now.
Maxwell's demon breaks the closure of the system, even if it sits inside the vessel.
Firstly, he needs an inflow of energy to do his job (the batteries must be charged), and secondly, the information that is embedded in this robot (demon) is also given FROM OUTSIDE, that is, there is an exchange of energy and information with the external environment.
And under these conditions, the work of the demon may well provide a solution to the Maxwell problem: the molecules will be distributed in speed. BUT! Thanks to the governing influence of the external rational principle.
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You can think of a mechanical Maxwell demon that will let through not molecules, but faster small particles in Brownian motion. Then quantum mechanics and thermodynamics do not work, only mechanics, and everything depends on the energy consumption by the demon to fix the particle, close the door, and the speed of the particles themselves, which depends on the temperature of the environment.
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The law of thermodynamics in this thought experiment of Maxwell is really violated (SELF-TRANSITION INTO A MORE ORDERED STATE!), But there is no need to fool your head because of the costs of opening-closing and heating the "valve" (let's say there is a membrane-diode - this is a technology problem, and not theoretical physics).
So, having sorted the molecules in the way described above, we get: the temperature of the fast molecules is higher than the initial one, BUT THE TEMPERATURE OF THE SLOW ones is PROPORTIONALLY BELOW. Therefore, the overall ordering of the system has not yet changed here (not counting the costs of the "sorter"). Let's say they are negligible.
Further, using the energy of fast molecules, for example, to perform work, we thereby lower their temperature, and, consequently, the overall temperature of the entire system. Having performed these manipulations with the gas a number of times, as a result, we will approach absolute zero and then the process of extracting energy by this method will become impossible. (So \u200b\u200bit’s not clear to me which perpetual motion machine the article is talking about). So we extracted energy, lowered the temperature, and increased the orderliness too much? molecules in this system. (they also increased the volume of gas - what about the order?).
This means that a closed system can self-cool down to 0 (in exchange for the release of an equivalent amount of energy minus the efficiency of the "sorter"), i.e. moving to a more orderly one? (and volume?) state, and SELF-TRANSITION INTO A MORE ORDERED STATE is not allowed by the 2 law of thermodynamics.
It seems to me that the amount of energy that was needed to create initial conditions, equally released as a result of cooling. But the ordering (in a foreign way, entropy) has not changed - it just seems to be in different units and volumes.
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\u003e\u003e In fairness it is worth saying that first it was necessary to spend (energetically) on creating clearly separated vacuum and gas, i.e. the system initially had potential energy and orderliness: (a clear region with gas and with vacuum), and as a result, gas is everywhere, but cold and of a larger volume. And how is this orderly measured?
Everything is much simpler. Where there is gas, the pressure is above zero. Where there is a vacuum, there pressure \u003d 0. The pressure difference is potential energy. The temperature difference is also potential energy. We extract them. And don't worry about the disorder - we're doing some work using cooled molecules - this work of entropy will induce enough to calm our fans.
\u003e\u003e It seems to me that the amount of energy that was needed to create the initial conditions is equally released as a result of cooling.
Yes, but the nice thing is that we didn't spend this energy :) If, say, we just take atmospheric air containing a mass of sufficiently energetic molecules, divide it with a barrier membrane, use the temperature difference and release cold air back - it will be free (free does not mean "eternal"!) engine. And along the way, the cooling of the climate is a hit for the countries of Central Africa.To answer
Yes, I do not argue. Molecules can be divided according to some principle. But this does not mean that their ensemble (fast or slow) under equilibrium conditions (when we can talk about the temperature of the system) will not redistribute the velocities among the particles according to the distribution function. And again there will be fast and there will be slow. Otherwise, we need to talk about a different model of the state of matter.
The funnel is interesting, no doubt. But we should talk, in my opinion, about the energy funnel - the heat one. A mechanical funnel is unlikely to "pull in" the particles, except perhaps the substance itself. Those. one should not forget that we are talking about some "representatives" of the ensemble, and not about its deterministic distribution, as, for example, at the interfaces. For an individual particle to have velocity is not a characteristic, since you need to immediately answer - what is this speed measured in relation to.
Once again I want to express my delight at the beauty of the task. And why does she hesitate? I think my decision is fine, although not necessarily true.
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But the question is formulated somewhat differently. The "molecular" engine is powered by temperature.
1. Where is the engine of the molecule?
2. Why should there be fast and slow molecules if the temperature is the same?
Due to collisions. Impact - speed dropped. Warming up - the speed has increased.
Well, the Demon has collected fast molecules. So the remaining slow ones will accelerate to the speed of the fast ones and the gradient will disappear!
2. Can a person orient the molecular "motors" to move in one direction?
Yes, by ionizing the gas and applying a field to it.
3. Is there any other possibility, besides the electromagnetic field, to "orient" molecular motors?
The movement of molecules when irradiated with infrared light is likely caused by the expansion of electron clouds. And the molecules in the mass of gas begin to "push" by the electron clouds. These "jolts" are probably the reason for the movement of molecules.
If there are few molecules or there is only one molecule at all, then under infrared irradiation, its electron clouds begin to repel from the walls of the vessel.
Are there any other considerations?
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There is a problem in physics that can be conventionally called the "reversibility-irreversibility" problem, and the thought experiment with Maxwell's demon is only one of the most striking illustrations of it. All physical laws, with one exception, are reversible in time, and the possibility of realizing Maxwell's demon does not contradict them! The exception is the second law of thermodynamics, which has many different formulations. The simplest of them is that heat cannot spontaneously pass from a body with a higher temperature to a body with a lower temperature. The possibility of the existence of the demon Maxwell contradicts exclusively this law. Thus, any attempts to prove the impossibility of Maxwell's demon, in which the second principle is not explicitly or implicitly used, are doomed to failure. It should be noted that all physical laws, including the second law, are a generalization of experimental data.
All these problems can be seriously discussed only by having a professional understanding of thermodynamics, statistical physics, quantum statistics, physical kinetics; future theoretical physicists study this mainly in their senior years for about six semesters. Non-professionals should not tackle this problem - no one is trying to independently calculate the orbits of asteroids or calculate the electronic structure of semiconductors, and this is much easier.
Some notes for professionals. 1) In a consistent way, entropy can be introduced only for an equilibrium system, while the second principle speaks in principle about nonequilibrium processes. 2) Statistical (through statistical weight) and thermodynamic (through heat and temperature) definitions of entropy do not always coincide. 3) From the quantum-mechanical (through the density matrix) definition of entropy it strictly follows that the entropy of a closed system remains unchanged. In general, there are many questions here.
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The author is wrong. History tells us that the truly worthwhile discoveries and inventions were made by “non-professionals”. Your so-called professionals are a bunch of boobies and sycophants. The Maxwell demon has been around for a long time. This device, invented in 1931, is called the Ranke-Hilsch tube. It allows you to separate a gas or liquid into hot and cold streams using a vortex. Moreover, much more heat is obtained than the energy expended to create a vortex.
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\u003e\u003e heat cannot spontaneously transfer from a body with a higher temperature to a body with a lower temperature. The possibility of the existence of Maxwell's demon contradicts only this law .... Non-professionals should not tackle this problem - no one is trying to independently calculate the orbits of asteroids or calculate the electronic structure of semiconductors, and this is much easier.
Non-professionals should not undertake anything at all - if something requires a professional decision, it is paid for and affects something. But what's wrong with _ just chatting on the free forum_ about something unrelated to your professional competence? Hardly anyone here seriously thinks that he "solves" something (except, perhaps, the author of the article ;-) And the orbits of asteroids, I think, are also calculated by someone - only in another branch :)))
Regarding the second law - such a point: how correct is it in general to identify "the transition of heat from one body to another" with "the division of one body into components (well, or two bodies)"?To answer
I completely agree with you. By the way, it will be right - heat cannot spontaneously pass from a body with a low temperature to a body with a higher temperature. The exact formulation of the second law belongs to W. Thomson and M. Planck: "In nature, a process is impossible, the full effect of which would consist only in the cooling of the heat reservoir and in the equivalent lifting of the load." But: in nature, Maxwell's demon exists if there is a possibility of creating a diode of molecular dimensions, a molecular diode. Such a diode is capable of converting the thermal motion of electrons into an ordered one, that is, into electricity... There is also a patent for a gradient tunneling diode with operating frequencies up to the ultraviolet range, which, according to the authors, is capable of converting even thermal fluctuations of electrons into electric current. This is our demon.
Let's do a thought experiment (like Grandpa Maxwell). We will not divide one body into components, but take an isolated container, divided by an impenetrable partition into two reservoirs. In a colder tank we place a lattice of nanorectennas (a rectenna is an antenna with a rectifier) \u200b\u200btuned to resonance with the radiation of fast, hot molecules of this reservoir, we connect the lattice with a bridge circuit of demons and - go ahead! We accumulate the resulting constant electric current and send it to the load (resistance) in a hotter tank and drown it to a victorious one (or we raise some kind of load). The second law rests. Of course, you cannot make a perpetual motion machine of the second kind in this way, since it is impossible to cool the first reservoir to infinity, but a clear violation of the second law is visible, right?To answer
Of course, this is not exactly Maxwell's demon, although the principle "take from the poor and give it to the rich" (let's call it "the inverse principle of Robin Hood") is ideologically close to our demon :)
And then I did not quite understand something: these "nanorectile" - do they still allow molecules or electrons to pass through? If molecules - then what kind of electronic current are we talking about? And if electrons (or ions in general), then what's the point of filtering them by speed? a slow electron is also an electron and the electric current will give as much as a fast one. True, this already turns out to be something like an ordinary electrolyte battery, only instead of electrolyte - gas (why?). The meaning of the second (hot) reservoir is not clear to me at all.Further (we proceed from the fact that we still filter molecules and try to transfer heat and not an electric charge). "connecting the lattice [nanorecten] to the demon bridge" - so who is rectifying here? rectennas or demons? if they are rectenna, then why are demons needed - and vice versa. If the rectennas are straightened, then the demon must sit IN EACH of them, and no additional bridges are needed to straighten the flow from the entire lattice, therefore, consolidation of flows from individual rectennas is not needed - that is, we return to the membrane (in which there is simply a "barrier" and "funnel" are united by the word "rectenna"). If rectennas only filter molecules by velocity (in both directions), then this is no longer a “rectenna”, but simply barriers, and all the most difficult (“funnel”) is done centrally. That is, this is just a constructive difference, not a fundamental one.
Filtering molecules by velocity is not a very difficult task. For example, we take an ionized (say +) gas and a monomolecular membrane of the same name (for structural rigidity, it can be attached to an easily permeable neutral frame). Only those gas molecules whose kinetic energy will be sufficient to overcome the Coulomb reaction will be able to slip through this membrane. It is important - the breakthrough (or rebound) of the molecule will be absolutely elastic - how much the molecule slows down on its way to the membrane - the same way it will accelerate when it rebounds (from the same or the other side). The required kin.energy threshold can be adjusted by selecting the size of the membrane cell and the charge on it.
The most difficult thing that may be required of a demon is to let the molecules go only in one direction. I don’t know how to teach a demon to do this, but you can make a knight's move and save him from this work. In principle, it is already enough that we have on one side of the membrane only fast molecules from the original body are guaranteed. Some of them will fly back, but some will remain. Already good. How to use it?