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| public:t-720-atai:atai-21:task-environment [2021/08/09 15:43] – [Maxwell's Demon] thorisson | public:t-720-atai:atai-21:task-environment [2024/04/29 13:33] (current) – external edit 127.0.0.1 |
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| | {{public:t-720-atai:510px-maxwell_s_demon.svg.png?500}} \\ Source: [[https://en.wikipedia.org/wiki/Maxwell%27s_demon|Wikipedia]] || | | {{public:t-720-atai:510px-maxwell_s_demon.svg.png?500}} \\ Source: [[https://en.wikipedia.org/wiki/Maxwell%27s_demon|Wikipedia]] || |
| | \\ A Thought Experiment | Imagine a container divided into two parts, A and B. Both parts are filled with the same gas at equal temperatures and placed next to each other. Observing the molecules on both sides, an imaginary demon guards a trapdoor between the two parts. When a faster-than-average molecule from A flies towards the trapdoor, the demon opens it, and the molecule will fly from A to B. Likewise, when a slower-than-average molecule from B flies towards the trapdoor, the demon will let it pass from B to A. The average speed of the molecules in B will have increased while in A they will have slowed down. Since average molecular speed corresponds to temperature, the temperature decreases in A and increases in B, contrary to the second law of thermodynamics. A heat extractor operating between the thermal reservoirs A and B could extract energy from this temperature difference, creating a perpetual motion machine. [ Adapted from [[https://en.wikipedia.org/wiki/Maxwell%27s_demon|Wikipedia]] ] | | | \\ A Thought Experiment | Imagine a container divided into two parts, A and B. Both parts are filled with the same gas at equal temperatures and placed next to each other. Observing the molecules on both sides, an imaginary demon guards a trapdoor between the two parts. When a faster-than-average molecule from A flies towards the trapdoor, the demon opens it, and the molecule will fly from A to B. Likewise, when a slower-than-average molecule from B flies towards the trapdoor, the demon will let it pass from B to A. The average speed of the molecules in B will have increased while in A they will have slowed down. Since average molecular speed corresponds to temperature, the temperature decreases in A and increases in B, contrary to the second law of thermodynamics. A heat extractor operating between the thermal reservoirs A and B could extract energy from this temperature difference, creating a perpetual motion machine. [ Adapted from [[https://en.wikipedia.org/wiki/Maxwell%27s_demon|Wikipedia]] ] | |
| | The Error | The thought experiment is flawed because the demon must be part of the same system that the container is part of; thinking (or computation, if the demon is a robot) requires time and energy, and so whatever heat is saved in the container will be spent to run the demon's thinking processes. | | | \\ The Error | The thought experiment is flawed because the demon must be part of the same system that the container is part of; thinking (or computation, if the demon is a robot) requires time and energy, and so whatever heat is saved in the container will be spent to run the demon's thinking processes. (This was first proposed in 1929 by Leo Szilard.) | |
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