{"title":"机械波中的负能量流","authors":"A. Matulis, A. Acus","doi":"10.3952/physics.v60i4.4356","DOIUrl":null,"url":null,"abstract":"A classical system, which is analogous to the quantum one with a backflow of probability, is proposed. The system consists of a chain of masses interconnected by springs and attached by other springs to fixed supports. Thanks to the last springs the cutoff frequency and dispersion appears in the spectrum of waves propagating along the chain. It is shown that this dispersion contributes to the appearance of a backflow of energy. In the case of the interference of two waves, the magnitude of this backflow is an order of magnitude higher than the value of probability backflow in the mentioned quantum problem. The equation of Green’s function is considered and it is shown that the backflow of energy is also possible when the system is excited by two consecutive short pulses. This classical backflow phenomenon is explained by the branching of energy flow to local modes that is confirmed by the results for the forced damped oscillator. It is shown that even in such a simple system the backflow of energy takes place (both instantaneous and average).","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.3000,"publicationDate":"2020-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Negative flow of energy in a mechanical wave\",\"authors\":\"A. Matulis, A. Acus\",\"doi\":\"10.3952/physics.v60i4.4356\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"A classical system, which is analogous to the quantum one with a backflow of probability, is proposed. The system consists of a chain of masses interconnected by springs and attached by other springs to fixed supports. Thanks to the last springs the cutoff frequency and dispersion appears in the spectrum of waves propagating along the chain. It is shown that this dispersion contributes to the appearance of a backflow of energy. In the case of the interference of two waves, the magnitude of this backflow is an order of magnitude higher than the value of probability backflow in the mentioned quantum problem. The equation of Green’s function is considered and it is shown that the backflow of energy is also possible when the system is excited by two consecutive short pulses. This classical backflow phenomenon is explained by the branching of energy flow to local modes that is confirmed by the results for the forced damped oscillator. It is shown that even in such a simple system the backflow of energy takes place (both instantaneous and average).\",\"PeriodicalId\":18144,\"journal\":{\"name\":\"Lithuanian Journal of Physics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.3000,\"publicationDate\":\"2020-10-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Lithuanian Journal of Physics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.3952/physics.v60i4.4356\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Lithuanian Journal of Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.3952/physics.v60i4.4356","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
A classical system, which is analogous to the quantum one with a backflow of probability, is proposed. The system consists of a chain of masses interconnected by springs and attached by other springs to fixed supports. Thanks to the last springs the cutoff frequency and dispersion appears in the spectrum of waves propagating along the chain. It is shown that this dispersion contributes to the appearance of a backflow of energy. In the case of the interference of two waves, the magnitude of this backflow is an order of magnitude higher than the value of probability backflow in the mentioned quantum problem. The equation of Green’s function is considered and it is shown that the backflow of energy is also possible when the system is excited by two consecutive short pulses. This classical backflow phenomenon is explained by the branching of energy flow to local modes that is confirmed by the results for the forced damped oscillator. It is shown that even in such a simple system the backflow of energy takes place (both instantaneous and average).
期刊介绍:
The main aim of the Lithuanian Journal of Physics is to reflect the most recent advances in various fields of theoretical, experimental, and applied physics, including: mathematical and computational physics; subatomic physics; atoms and molecules; chemical physics; electrodynamics and wave processes; nonlinear and coherent optics; spectroscopy.