Maxwell's demon, quantum demon. Maxwell's Demon: converter of information into energy History of Maxwell's Demon
The thought experiment is as follows: suppose a vessel with a gas is divided by an impenetrable partition into two parts: right and left. In the partition there is a hole 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 a long period of time, the “hot” (fast) molecules will end up in the right vessel, and the “cold” ones will “remain” in the left one.
Thus, it turns out that Maxwell’s demon allows you to heat the right side of the vessel and cool the left without additional energy supply to the system. The entropy for a system consisting of the right and left parts of the vessel is greater in the initial state than in the final state, which contradicts the thermodynamic principle of non-decreasing entropy in closed systems (see the Second Law of Thermodynamics)
The paradox is resolved if we consider a closed system that includes Maxwell's demon and the vessel. For Maxwell's demon to function, energy must be transferred to it from a third-party source. Due to this energy, the separation of hot and cold molecules in the vessel occurs, that is, the transition to a state with lower entropy. A detailed analysis of the paradox for the mechanical implementation of the demon (ratchet and pawl) is given in the Feynman Lectures on Physics, vol. 4, as well as in Feynman's popular lectures "The Nature of Physical Laws."
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 remember the results of measuring speeds (erasing them from the demon’s memory makes the process irreversible). Since memory is finite, at a certain point the demon is forced to erase old results, which ultimately leads to an increase in the entropy of the entire system as a whole.
The success of Japanese physicists
For the first time, Japanese physicists were able to experimentally achieve an increase in the internal energy of a system, using only information about its state and without transferring additional energy to it.
The generation of energy from information was first theoretically described by British physicist James Maxwell in his thought experiment. In it, a creature, later called "Maxwell's demon", guarded the door between two rooms. The demon, knowing the energy of the molecule approaching the door, opens the passage only for “fast” molecules, closing the door in front of “slow” ones. As a result, all the “fast” molecules will be in one room, and all the slow ones in the other, and the resulting temperature difference can be used for practical purposes.
The implementation of such a “demonic” power plant requires much greater energy costs than can be extracted from the resulting temperature difference, so real engines operating on this principle have never been seriously considered by scientists. However, interest in such systems has resurfaced recently with the development of nanotechnology.
The authors of the study, Japanese physicists led by Masaki Sano from the University of Tokyo, put into practice a thought experiment involving “Maxwell’s demon.”
The scientists used a polymer object about 300 nanometers in size, resembling a bead. Its shape is chosen so that rotating clockwise is energetically more beneficial for it, since this is accompanied by the release of mechanical energy. Counterclockwise rotation, on the contrary, leads to “twisting” of the bead and an increase in the mechanical energy stored in it.
The bead was placed in a special solution, and due to its small size, it began to take part in Brownian motion and rotate - both clockwise and counterclockwise.
The researchers used special equipment to track each turn of the bead, and as it rotated counterclockwise, they applied an electrical voltage to the container in which it was located. This operation did not transfer additional energy to the system, but at the same time it did not allow the bead to “unwind” back. Thus, using only information about where the bead turned, scientists were able to increase its supply of mechanical energy only due to the energy of Brownian motion of molecules.
The law of conservation of energy is not violated. According to Sano's calculations, the efficiency of converting information into energy in their experiment was 28%, which is consistent with theoretical calculations.
Such a mechanism could be used to operate nanomachines or molecular mechanisms, says Vlatko Vedral, a physicist at the University of Oxford who did not take part in Sano's experiment, whose opinion is cited by the online publication Nature News.
“It would be very interesting to discover the use of this principle of energy transfer in living systems,” the scientist added.
What's happened " Maxwell's demon"And why has it been worrying the minds of great scientists for a century and a half? It’s simple. Scientists are looking for processes that would allow heat to move from less heated bodies to hotter bodies. But we know that heat can only move from hot bodies to cold ones This is called the second law of thermodynamics, which was challenged by "Maxwell's demon".
The great English scientist James Maxwell tried to solve this problem in 1871. A certain fantastic creature, “Maxwell’s demon,” possessed the functions of a similar mechanism. "Maxwell's Demon" has such sophisticated abilities that it can follow every single molecule in its movements and know its speed. If we take a vessel divided into two parts by a partition, and “Maxwell’s demon” sits at the door in the partition, we can force it to open the door only in front of fast or only in front of slow molecules. “Maxwell’s Demon” will allow fast molecules to pass into one part of the vessel, and slow molecules into another, then in one part of the vessel both the temperature and pressure will be higher than in the other, that is, we will receive an unlimited supply of energy without the cost of work. for a system consisting of the right and left parts of the vessel, in the initial state it is greater than in the final state, which contradicts the thermodynamic principle of non-decreasing entropy in closed systems.
The paradox is resolved if we consider a closed system that includes “Maxwell’s demon” and a vessel. For the functioning of the "Maxwell's demon" it is necessary to transfer energy to it from a third-party source. Due to this energy, hot and cold molecules in the vessel are separated. Due to this energy, the separation of hot and cold molecules in the vessel occurs, that is, the transition to a state with lower entropy.
With the development of the 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 remember the results of measuring speeds (erasing them from the demon’s memory makes the process irreversible). Since it is finite, at a certain moment “Maxwell’s demon” is forced to erase old results, which ultimately leads to an increase in the entropy of the entire system as a whole.
Many times scientists have convincingly proven that “Maxwell’s demon” is just a joke of the great physicist. Indeed, "Maxwell's demon" in a vessel with two molecules is not effective; in half the cases they could end up in any one part of the vessel. If there are many molecules, then the probability of such an event is extremely low.
However, passions do not subside, “Maxwell’s demon” is trying to find new arguments in its defense. In one of the scientific journals, in an article devoted to this problem, it is seriously stated that “Maxwell’s demon” exists only in the form of a quantum generator - which separates excited molecules with high energy from unexcited molecules.
However, there is still no strict evidence that "Maxwell's demon" exists, nor strict refutation of this. "Maxwell's Demon" fuels interest in further searches.
Maxwell's demon, quantum demon
James Maxwell's delusional idea, when he came up with a power capable of reversing time in 1867, described the awareness of a “demon” who could cancel 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 disorder in closed systems.
More on Demon Awareness
Maxwell's imaginary demon was in a closed box and reversed the flow of molecules, recreating the degrading order. Below you see a smiling face that represents 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 the hot material on one side of the box and the cooler material on the other so that the original "order" (of hot and cold) is not degraded. The demon arranges everything so that in a closed system, energy should not become less accessible, or information should not be lost. Using awareness to open and close the partition separating two volumes of gas in a container, the demon reverses the second law of thermodynamics. So far, no one has managed to find such a demon or create it in the generally accepted reality.
And yet Maxwell's fantasy may be more true than he himself realized. It seems to me that he could be projecting our capacity for awareness, our ability to notice “nanoscopic” events or advances. This almost unmeasurable quantum awareness is the ability of awareness that can make choices in dreamland.
Maxwell's demon is, in fact, a potential hero of psychotherapy, for it is that part of us that restores order by seeing patterns where 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 mainstream reality that uses a minimum of awareness. Maxwell's Demon is a representation of our clear awareness operating at the unmeasurable subatomic levels of nano-events, and can, at the very least, alleviate the sensation of aging.
The psychological principle projected onto Maxwell's demon is:
Seeing the order hidden within the chaos of mainstream reality creates more energy available.
Ignoring or even suppressing subtle symptom signals is depressing and draining. Recognizing your symptoms as wake-up calls for attention allows you to create order out of disorder and generally gives you more energy to work. Marginalizing 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 didn't know about wave functions yet; they were to appear fifty years later. But if he were alive today, he would certainly be interested in the kind of awareness that can notice and track subtle trends, the quantum waves of dreamland, and the guidance they give us. I imagine he would say that ignoring all the subtle feelings flickering in our awareness contributes to emptiness and makes us feel older than we really are.
The following exercise gives you the 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.
An exercise in awareness of negentropy
1. Sit back and think about how you feel about aging. What do you like about it? What's not to like?
For example, many people like the opportunity to realize their potential, but don't like the loss of energy and what they call "attractiveness." Some people have the idea that life is coming to an end.
2. When you are ready, look around for something you can lift or push. If you're standing in a room, pick up a chair or push off one of the walls and see how much energy you have available. When lifting or pushing, ask yourself, “How much of my energy is available to me now?” Record this amount of energy. How much is it - 85%, 50% or 15%? How old do you feel?
For example, when I picked up a chair today, it felt heavier than it should be. I would say that I have about 50% of my energy available.
3. The amount of available or isometric energy you have depends very much on your sense of order within yourself. So now think about one area of your life that feels “disorganized.” If possible, choose a new area rather than relationships or bodily symptoms, since we have already worked on them before.
For example, you may feel unorganized about your work, your finances, or, say, the clutter on your desk or the way you use your time. Perhaps what is “disorderly” is your attitude towards criticism.
Don't lose sight ignored areas of your life that need order. If there are many such areas, choose only one for now - any will do. How do you avoid this area? In what sense is this area “closed”? Do you avoid or “forget” about issues related to this area? How do you forget these questions? Do you try to get more sleep, or do you just complain about them? Do you get them out of your head? Do you watch TV or go to the movies instead of tidying up this area?
4. Now, thinking about this disordered area, imagine what kind of “space” it is in. What colors and movements take place in this space? Describe in your own words the characteristics of the space that contains this disordered area of life.
For example, does it look gray or cloudy? Spinning and stirring?
Can you identify some place outside of your body where this “disordered area” could be, where this space would be located? (eg in front of you, behind you, etc.). Draw this disordered area next to your body.
(Inscriptions in the picture, from top to bottom: Finances are in complete chaos, big storm clouds, oh my poor head! A disordered area affects the head)
In the picture, the disordered area is related to finances and appears to be overhead.
How does the part of your body closest to this space feel? Do you have bodily symptoms near this area? Choose a bodily symptom or one of the symptoms to work on, say the one to which you paid the least attention. Is this symptom related to your feeling of aging?
5. Focus on the symptom in that area of the 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 recipient of that energy or action. In other words, imagine, so to speak, a “symptom creator” and a “symptom recipient.”
One way to imagine these two figures is to make it as strong as possible feel into symptom, or imagine that you feel it. Then exaggerate the 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 pounding headache, you might emphasize the sensation of the pounding until you have an angry figure pounding on the table and a sensitive figure (say, the table itself) being hurt by the pounding.
Try to find out the message that each figure expresses.
For example, the angry figure may be saying, “I have to fight my way through things,” while the other is saying, “Please don't do that, it's too rough and it's hurting 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 into the picture and resolves the conflict between these two energies. For example, imagine a skilled mediator, a genie, a spirit, a cartoon character - someone capable of dealing 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 burdened 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 figures.
The priest blessed both parts of her, and they softened.
(Captions under the pictures, from left to right: The part that was burdensome; the Helping Spirit; the ambitious part)
At some point you might try to become your spirit helper, your demon of quantum awareness. Enter the psychologically closed system of your dreaming body and intervene; facilitate the resolution of conflict between the two parts in this symptom area.
Imagine the resulting story. Let the quantum demon intervene magically and find a solution.
A reader whose symptoms lacked the God the priest represented. 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 breath to focus on the feeling of this conflict resolution, and if possible, feel a sense of relief in the symptom area.
8. Imagine how you could use this solution in the disorganized area of your life where you began this exercise. Remember the original disorder - its space, colors and movements - and note (or better yet, draw) how this area has transformed. Don't "work" on it, just let it happen internally until things change for the better.
9. Finally, return to the wall or chair and, carefully, look again at what effect this work may have had on your sense of energy available to do what you need to do in life. What changes are you noticing in your available energy?
From the book Hyperborean teaching author Tatishchev B Yu3.3. Demon of DEGENERATION. What are these “mechanisms of degeneration”? For the answer, first let’s turn to the talented and honest book of the former leader No. 2 of the political movement of “Western” Zionism, a student of psychiatrist Professor Cesare Lombroso, Dr. Max
From the book Temple Teachings. Instructions of the Teacher of the White Brotherhood. Part 2 author Samokhin N.DEMON OF GREED A wanderer with a great soul stopped on his way through the desert of a fleeting life when he saw a kneeling woman, with her hands folded in prayer on her chest, her gaze fixed on him, from whose lips were prayers for forgiveness and remission of sin. Listening
From the book Me and My Big Space author Klimkevich Svetlana TitovnaQuantum Leap 589 = Man carries within himself the creative energy of God – Love = 592 = Great Spiritual Awakening – Sign of Cosmic Cycles = “Number Codes”. Book 2. Kryon Hierarchy 27 01/2012 “Space of Time - Time of Space...” - words upon waking up. I Am That I Am
From the book Quantum Magic author Doronin Sergey Ivanovich4.1. Quantum processor
by Gardiner PhilipQuantum World I am inspired by the idea that in the Universe (from the micro to the macro level, from the cosmic movement of planets to the interaction of electrons, from microscopic silicon dioxide to the man-made Egyptian pyramid) there is a universal model, not
From the book Gates to Other Worlds by Gardiner PhilipThe Quantum God While working on this book, I took one day off from quantum physics and went to Lichfield, Staffordshire. I had a wonderful time in the beautiful, esoteric feeling of Lichfield Cathedral, looking at its amazing façade
From the book XX century. Chronicle of the inexplicable. Phenomenon after phenomenon author Priyma AlexeyTHE DEMON JUMPED OUT OF THE MOUTH Now let's move on to another mind-blowing story. It happened with the 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 authenticity of her story. In July 1995, to Makhotina From the book Geopsychology in Shamanism, Physics and Taoism author Mindell Arnold
From the book The Power of Silence author Mindell ArnoldAppendix III. MINDS: The Quantum Mind In the following pages I summarize some of the many meanings I associate with the term "quantum mind". A technical - yet popularly stated - description of the quantum mind can be found in the books of Nick Herbert
From the book The end of the world has not happened and will not happen author Gusev Anatoly IvanovichBony demon In 1999, a group of English paleontologists worked in the area of the town of Uulakh in the Mongolian Gobi Desert. Their goal was to explore a dinosaur cemetery in a remote mountain gorge. From local residents, scientists heard a legend about someone living in the gorge.
author author unknownAn interesting story about how a demon named Rush came to a monastery to hire himself out. 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 would pray to Him day and night for the founders and
From the book The Story of Brother Rush author author unknownAbout how a demon named Rush came to the house of a noble lady and secretly brought her to his master - Hello, beautiful, kind lady, the most beautiful of all living. My master sends his greetings to you and asks you to come and talk to him. He asks him
From the book Secrets of the Brain. Why do we believe in everything by Shermer MichaelPhysicists from Finland, Russia and the USA have pioneered Maxwell's autonomous electron 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 the operation of computers, says Lenta.ru.
The intrigue around Maxwell's demons has persisted in science for 150 years. The concept of a supernatural being was proposed in 1867 by British physicist James Clerk Maxwell. We are talking about a certain device that functions in such a way that it leads to a violation (apparently) 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 with an inner wall with a small hatch. By opening and closing the hatch, Maxwell's demon separates fast (hot) and slow (cold) particles. As a result, a temperature difference arises 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, it makes impossible the spontaneous transfer (that is, without doing work) of heat from a colder body to a hotter one or, what is the same thing, a decrease in the entropy (a measure of disorder) of an isolated system. In the formulation of the Frenchman Sadi Carnot, this law sounds like this: a heat engine with an efficiency factor of one hundred percent is impossible.
The second law of thermodynamics was finally formulated in the 19th century. Then it was a law for a number of special cases (its fundamental nature became clearer later). Physicists looked for contradictions in it, and one of them (along with the thermal 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 lovers. In the 20th century, the fame of Maxwell's demon was eclipsed by Schrödinger's cat (or cat). Meanwhile, like a pet from quantum mechanics, the British physicist's demon served as the source of many important discoveries. In particular, thanks to him, the thermodynamic theory of information and the related idea of information entropy arose.
In the 1960s, Rolf Landauer, a researcher at the American company IBM (International Business Machines), formulated the principle that bears his name. He connected the loss of a bit of information in any physical system with the release of a corresponding amount of heat (or, what is the same, an increase in thermodynamic entropy). Landauer's work had fundamental significance for computing that continues 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 a device (primarily its power and size) at which information is destroyed. Man-made processors have gone from dissipating billions of times more heat than predicted by Landauer's principle to today's only thousands of times more.
Let there be a memory cell containing information encoded in bits (with values zero and one). If you destroy it (that is, transform it into a state containing only zeros or ones), heat will be released. In the language of thermodynamics, this means that the entropy of the system turns to zero, since the maximum ordered state (described only by zeros or ones) has been achieved. Landauer liked to repeat that “information is a physical quantity,” this 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 system states corresponded to the logical values zero and one. When the system was transferred to one state, the information was erased. The machine took into account many nuances, in particular fluctuations, whose role grew along with the decrease in the depth of the pits. Using 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 Landauer's 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 velocities of the particles. At some point, the memory becomes full, and the daemon needs to erase it to continue working. This requires doing work exactly equal to the work that 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 erasing the demon's memory. Could she be some kind of super demon influencing a minor 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 Maxwell's demon with autonomous operation.
Japanese scientists managed to implement it for the first time in 2010. Their electromechanical model is a polystyrene bead with a diameter of about 300 nanometers placed in an electrolyte. The electromagnetic field prevented the bead from moving downwards, as a result of which it gained mechanical (potential) energy proportional to the work of the field. Maxwell's demon in such a system was the observer and his scientific instruments, the functioning of which requires energy. The latter circumstance again does not allow one to violate the second law of thermodynamics. Unlike Japanese scientists, their colleagues from Finland, Russia (Ivan Khaimovich from the Institute of Physics of Microstructures of the Russian Academy of Sciences) and the USA for the first time created not an electromechanical, but a completely electronic Szilard machine (Maxwell's autonomous demon).
The system is based on a single-electron transistor, which forms a small copper island connected to two superconducting aluminum terminals. Maxwell's demon controls the movement of electrons of different energies in a transistor. When the particle is on the island, the demon attracts it with a positive charge. If an electron leaves the island, the demon repels it with a negative charge, which causes the transistor's temperature to drop and the demon's temperature to rise.
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 it looks as if Maxwell's demon knows about the state of the system and is able to control it. The electronic demon makes it possible to carry out a large number of measurements in a short period of time, and low temperatures in the system make it possible to record extremely small changes in it. This system also does not violate the second law of thermodynamics and is consistent with the intuitive idea that information can be used to do work.
Why do scientists need such research? On the one hand, they are of clear academic interest, since they allow the study of microscopic phenomena in thermodynamics. On the other hand, they show how important the production of entropy is from the information received by the demon. This is precisely what the authors of the study believe can be useful for the design of qubits (quantum analogues of classical bits) of quantum computers, even despite the emerging progress in reversible computing, a story about which is beyond the scope of this article.
This paradox has long been solved. In 1929, Leo Szilard, a private assistant professor at the University of Berlin (later one of the most prominent participants in the Manhattan Project), showed that even an ideally functioning demon increases its own entropy every time it receives information about the movement of a molecule. The entropy of the entire system remains unchanged, because the demon and the gas form a single whole. Fate sometimes travels in strange ways. In his later years, Leo Szilard had the opportunity to be treated by American cardiologist Alvin Reisen. He had a little son, Mark, who, when he grew up, became a physicist and professor at the University of Texas at Austin. In recent years, he and his colleagues have developed a new method for ultra-deep cooling of gases, which uses a laser device... similar in operation to Maxwell's demon.
Reisen method
For decades, physicists have been bringing gas to microkelvin temperatures using Doppler absorption of laser radiation. However, Professor Reisen explained to Popular Mechanics why this method does not suit him: “It is good, but too picky. This way you can cool only individual substances, mainly alkali metal vapors. Our method is much more universal. It is applicable to any gas whose atoms or molecules can exist in two long-lived metastable quantum states. There are many substances that meet this requirement.”
A classic demon guarding the door in the partition of a vessel (left) and a diagram of a three-level system in Reisen’s experiment (right). Atoms in a magnetic-gravitational trap with the help of optical pumping by a laser (in this case this is the demon) are transferred from state B to state A through an intermediate state).
The method developed by Reisen's group involves first cooling the gas to a few millikelvins using one of the reliable traditional methods and trapping it in a magnetic trap that is targeted by two lasers. The beam of one laser intersects the trap cavity in the middle, and the other illuminates only one half - for example, the right.
“For definiteness, we will assume that the gas is atomic,” says Professor Reisen. - Let's call one of the possible states of its atoms blue, the other - red. Let's configure the central laser so that its radiation repels atoms that are in the red state. The second laser converts atoms from a blue state to a red state. Let's assume that initially all atoms are blue. Let's fill the trap with them and turn on the central laser. Since there are no red atoms, the radiation and gas do not interact in any way. Now let's apply current to the side laser. Each atom that encounters a photon emitted by it will go from a blue state to a red state. If such a “recolored” atom approaches the central plane of the trap, it will be thrown back by the beam of the first laser. As a result, red atoms will accumulate in the right zone, and the left one will become empty. So our pair of lasers works similarly to Maxwell's demon. At the same time, the temperature of the gas does not change, but its pressure naturally increases.”
Cold gas, hot radiation
However, where is the cooling effect? “Now,” Professor Reisen continues his explanation, “we will manipulate the central laser in such a way that the gas slowly fills the entire cavity of the trap. With this expansion, the gas cools. That's all, actually - the goal has been achieved. This theory has already been tested experimentally three years ago. Then we conducted the first experiment - we cooled rubidium vapor by a thousand times (from millikelvins to microkelvins). We call this technique single-photon cooling because the atom only needs to scatter one photon to transition between states. But the Doppler method cools the gas by stopping the atoms, which requires many photons.”
What about entropy? “She’s fine,” Professor Reisen reassured us. - When the gas collects in the right zone, its entropy will naturally decrease. However, let us remember that laser radiation quanta, when meeting atoms, are chaotically scattered in all directions. At the same time, the entropy of radiation increases, and this increase completely compensates for the decrease in the entropy of the gas. So the laser demon works in full accordance with Szilard's theory. Of course, Maxwell himself and several generations of physicists did not believe in the real feasibility of such subtle manipulation of gas particles. Even twenty years ago I would have considered this pure fantasy. But science often achieves seemingly impossible goals—and this is just such a case. I think Maxwell would like our development.”