MOSCOW, February 7. /TASS/ The law of non-decrease of entropy in closed systems, which is one of the formulations of the second law of thermodynamics, can be broken, said the press service of the Moscow Institute of Physics and Technology (MIPT).
An international team of scientists under the guidance of Gordey Lesovik, Chief Researcher at MIPT’s Laboratory of Quantum Theory of Information and the L. D. Landau Institute for Theoretical Physics of the Russian Academy of Sciences discovered that entropy can decrease in quantum systems. The results of the study have been published in the journal Scientific Reports from the Nature publishing group.
"We have discovered Maxwell's demon which can reduce the entropy in the system," Lesovik said.
Maxwell's demon is a mythic creature invented by British physicist James Clerk Maxwell in the second half of the 19th century in order to explain the paradox of the second law of thermodynamics. The demon should increase the orderliness of a system which by itself cannot grow in the isolated system according to the laws of physics.
In the 1870s, Ludwig Boltzmann formulated the principle of growth of entropy (disorder) in his H-theorem which postulated that the value of entropy in a closed system can only increase or remain constant. For a long time, this theorem could not be proven in the framework of traditional statistical physics without additional restrictions. After establishing quantum mechanics, scientists suggested that the H-theorem was rooted in the quantum world. In the quantum theory of information, the important results were obtained which describe conditions when the entropy of a system does not diminish.
The group led by Lesovik first formulated the H-theorem in the language of quantum physics and for several years had tried to find proof of that theorem. As a result, the researchers uncovered conditions when the second law of thermodynamics can be locally breached. This can happen in quantum systems of relatively small but macroscopic size measuring a few centimeters or even meters.
The notable difference between the classical and quantum approach is that in classical physics, the decrease of entropy is connected to the transmission of heat energy while in the quantum world, the reduction of entropy can take place without energy transfer but due to quantum entanglement.
According to Lesovik, the researchers are planning to perform experiments in the near future to verify the effect. Such experiments will open the door to creating a new type of quantum coolers and power generators.