arXiv - PHYS - Popular Physics最新文献_第10页

Emergent reprogrammable mechanical memory in soft rods network via friction tuning 基于摩擦调谐的软杆网络紧急可编程机械记忆

arXiv - PHYS - Popular Physics Pub Date : 2023-10-02 DOI: arxiv-2310.01115

Harsh Jain, Shankar Ghosh

引用次数: 0

Why every observatory needs a disco ball 为什么每个天文台都需要一个迪斯科球

arXiv - PHYS - Popular Physics Pub Date : 2023-09-25 DOI: arxiv-2309.14173

Robert J. Cumming, Alexander G. M. Pietrow, Livia Pietrow, Maria Cavallius, Dominique Petit dit de la Roche, Casper Pietrow, Ilane Schroetter, Moa Skan

引用次数: 0

An Information-Theoretic Analog of the Twin Paradox 双生悖论的信息论类比

arXiv - PHYS - Popular Physics Pub Date : 2023-09-21 DOI: arxiv-2309.11862

Mladen Kovačević, Iosif Pinelis, Marios Kountouris

引用次数: 0

A plethora of the Earth-like planet: Ramifications of a Fuzzy World 大量类地行星：模糊世界的影响

arXiv - PHYS - Popular Physics Pub Date : 2023-09-20 DOI: arxiv-2403.12441

Ian von Hegner

{"title":"A plethora of the Earth-like planet: Ramifications of a Fuzzy World","authors":"Ian von Hegner","doi":"arxiv-2403.12441","DOIUrl":"https://doi.org/arxiv-2403.12441","url":null,"abstract":"One primary reason for the formulation of the term Earth-like planet and the\u0000search for such planets in the galaxy are due to the fact that life has arisen\u0000on such a world. Thus, this search seems justifiable since it is here known\u0000what one is looking for. However, the Earth-like concept represents an attempt\u0000to set up sharp boundaries for an inhabited planet, even though nature often\u0000comes as continua. The analyzes in this work show that the term does not\u0000represent a clear cut entity as a general Earth likeness cannot be abstracted.\u0000Thus, the complex variation of environment and life means that the singular\u0000term Earth-like planet is more appropriately treated as a fuzzy world. Such a\u0000fuzzification has the consequence that the term is not only more limited than\u0000assumed, it may even be deceptive, as an Earth-like planet on the one hand can\u0000be in a segment where it does not seem particularly Earth-like, but still\u0000possesses life, but on the other hand can appear very Earth-like but not\u0000possess life anyway. An atmosphere can provide a biosignature by being\u0000displaced from thermodynamic equilibrium, derived from antagonistic adaptation,\u0000in which life as a double edged sword on the one hand continuously makes the\u0000external environment less favorable for itself, while on the other hand it\u0000increases its capacity to do so. Yet, there is an issue with using this as a\u0000search criterion for potentially inhabited worlds, as such planets can give\u0000impressions that do not reflect what has gone on, it can even give a ghost\u0000biosignature. These novel analyzes do not represent a limitation in the search\u0000for Earth-like planets, as the plethora of Earth-like planets shows the\u0000possibility that the number of inhabited worlds can be large, but it does\u0000represent a limitation in the search for life on such worlds.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"2013 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140165203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fukushima tritiated water release -- what is the polemic all about? 福岛氚化水排放——争论的焦点是什么?

arXiv - PHYS - Popular Physics Pub Date : 2023-09-13 DOI: arxiv-2309.07083

Hans Peter Beck

引用次数: 0

Swarming Proxima Centauri: Optical Communication Over Interstellar Distances 星群比邻星:星际距离上的光通信

arXiv - PHYS - Popular Physics Pub Date : 2023-09-13 DOI: arxiv-2309.07061

T. Marshall Eubanks W. Paul Blase Andreas Hein Adam Hibberd Robert G. Kennedy III

{"title":"Swarming Proxima Centauri: Optical Communication Over Interstellar Distances","authors":"T. Marshall Eubanks W. Paul Blase Andreas Hein Adam Hibberd Robert G. Kennedy III","doi":"arxiv-2309.07061","DOIUrl":"https://doi.org/arxiv-2309.07061","url":null,"abstract":"Interstellar communications are achievable with gram-scale spacecraft using\u0000swarm techniques introduced herein if an adequate energy source, clocks and a\u0000suitable communications protocol exist. The essence of our approach to the\u0000Breakthrough Starshot challenge is to launch a long string of 100s of\u0000gram-scale interstellar probes at 0.2c in a firing campaign up to a year long,\u0000maintain continuous contact with them (directly amongst each other and via\u0000Earth utilizing the launch laser), and gradually, during the 20-year cruise,\u0000dynamically coalesce the long string into a lens-shaped mesh network\u0000$sim$100,000 km across centered on the target planet Proxima b at the time of\u0000fly-by. In-flight formation would be accomplished using the \"time on target\"\u0000technique of grossly modulating the initial launch velocity between the head\u0000and the tail of the string, and combined with continual fine control or\u0000\"velocity on target\" by adjusting the attitude of selected probes, exploiting\u0000the drag imparted by the ISM. Such a swarm could tolerate significant attrition, e.g., by collisions\u0000enroute with interstellar dust grains, thus mitigating the risk that comes with\u0000\"putting all your eggs in one basket\". It would also enable the observation of\u0000Proxima b at close range from a multiplicity of viewpoints. Swarm\u0000synchronization with state-of-the-art space-rated clocks would enable\u0000operational coherence if not actual phase coherence in the swarm optical\u0000communications. Betavoltaic technology, which should be commercialized and\u0000space-rated in the next decade, can provide an adequate primary energy storage\u0000for these swarms. The combination would thus enable data return rates orders of\u0000magnitude greater than possible from a single probe.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"135 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Application of the Thermodynamics of Radiation to Dyson Spheres as Work Extractors and Computational Engines, and their Observational Consequences 辐射热力学在戴森球作为功提取器和计算引擎中的应用及其观测结果

arXiv - PHYS - Popular Physics Pub Date : 2023-09-12 DOI: arxiv-2309.06564

Jason T. Wright

{"title":"Application of the Thermodynamics of Radiation to Dyson Spheres as Work Extractors and Computational Engines, and their Observational Consequences","authors":"Jason T. Wright","doi":"arxiv-2309.06564","DOIUrl":"https://doi.org/arxiv-2309.06564","url":null,"abstract":"I apply the thermodynamics of radiation to Dyson spheres as machines that do\u0000work or computation, and examine their observational consequences. I identify\u0000four properties of Dyson spheres that complicate typical analyses: globally,\u0000they may do no work in the usual sense; they use radiation as the source and\u0000sink of energy; they accept radiation from a limited range of solid angle; and\u0000they conserve energy flux globally. I consider three kinds of activities:\u0000computation at the Landauer limit; dissipative activities, in which the energy\u0000of a sphere's activities cascades into waste heat, as for a biosphere; and\u0000\"traditional\" work that leaves the sphere, such as radio emission. I apply the\u0000Landsberg formalism to derive efficiency limits in all 3 cases, and show that\u0000optical circulators provide an \"existence proof\" that greatly simplifies the\u0000problem and allows the Landsberg limit to be plausibly approached. I find that\u0000for computation and traditional work, there is little to no advantage to\u0000nesting shells (as in a \"Matrioshka Brain\"); that the optimal use of mass is\u0000generally to make very small and hot Dyson spheres; that for \"complete\" Dyson\u0000spheres we expect optical depths of several; and that in all cases the\u0000Landsberg limit corresponds to a form of the Carnot limit. I explore how these\u0000conclusions might change in the face of complications such as the sphere having\u0000practical efficiencies below the Landsberg limit (using the endoreversible\u0000limit as an example); no use of optical circulators; and swarms of materials\u0000instead of shells.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"93 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Majorana fermion induced power-law scaling in the violation of Wiedemann-Franz law 马约拉纳费米子在违反Wiedemann-Franz定律的情况下诱导幂律缩放

arXiv - PHYS - Popular Physics Pub Date : 2023-09-11 DOI: arxiv-2309.05492

Ritesh Das, Colin Benjamin

引用次数: 0

Switching global correlations on and off in a many-body quantum state by tuning local entanglement 通过调整局部纠缠，在多体量子态中打开和关闭全局相关性

arXiv - PHYS - Popular Physics Pub Date : 2023-09-11 DOI: arxiv-2309.05504

Colin Benjamin, Aditya Dash

引用次数: 0

Making Habitable Worlds: Planets Versus Megastructures 创造适宜居住的世界:行星vs巨型建筑

arXiv - PHYS - Popular Physics Pub Date : 2023-09-08 DOI: arxiv-2309.06562

Raghav NarasimhaCHRIST University, Bangalore, India, Margarita SafonovaIndian Institute of Astrophysics, Bangalore, India, C. SivaramIndian Institute of Astrophysics, Bangalore, India

{"title":"Making Habitable Worlds: Planets Versus Megastructures","authors":"Raghav NarasimhaCHRIST University, Bangalore, India, Margarita SafonovaIndian Institute of Astrophysics, Bangalore, India, C. SivaramIndian Institute of Astrophysics, Bangalore, India","doi":"arxiv-2309.06562","DOIUrl":"https://doi.org/arxiv-2309.06562","url":null,"abstract":"In 2015, a star KIC 8462852 caught the world's attention due to a paper by\u0000citizen scientists who noticed its seemingly unexplainable brightness\u0000variations. The forward theory was offered - KIC 8462852 is surrounded by a\u0000Dyson sphere, a megastructure made by an alien civilization to collect all\u0000energy output from their star. Finally, in 2018, its light curve showed\u0000chromaticity more characteristic of the dust (from comets or asteroids) rather\u0000than of something made from solid material, but the world was woken up to the\u0000idea of megastructures. But, in Dyson's time, only Solar System planets were\u0000known; it took more than 20 years to realize that nature has no problem making\u0000planets and does it with a flair -- the total number of planets in the Galaxy\u0000is estimated to be in billions. With such abundance of planets, there would be\u0000no need to destroy the entire planetary system to make one sphere. Instead, a\u0000civilization can expand to a system that has planet(s) in the habitable zone\u0000(HZ), or a planet can be moved into it. Alternatively, a free-floating planet\u0000(FFP) can be captured and moved into the HZ. These shifts can be performed at a\u0000constant low-thrust acceleration using high power directional lasers, resulting\u0000in a gradual spiral transfer from one orbit to another. We propose here to\u0000search for ETI by looking for high-power laser technosignatures and consider\u0000merits of such signatures. We suggest to specifically pay attention to the\u0000multiple planetary systems that have Strange Exoplanetary Architectures (SEA) -\u0000unusual planetary arrangements that cannot be explained by current planetary\u0000formation theories, because these could be the result of ETI moving planets\u0000intentionally to suit their needs.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"7 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0