We present emergent mechanical memory storage behavior in soft cellular materials. The cellular materials are a network of soft hyperelastic rods which store shape changes, specifically local indentation. This happens under an applied global compressive strain on the material. The material transits under strain from an elastic state (capable of `forgetting' any applied indentation after un-indentation) to plastic state (indefinitely storing the shape change due to indentation). The memory can be erased via removal of applied global strains and is therefore re-programmable. We characterise this behaviour experimentally and present a simple model that makes use of friction for understanding this behavior.
{"title":"Emergent reprogrammable mechanical memory in soft rods network via friction tuning","authors":"Harsh Jain, Shankar Ghosh","doi":"arxiv-2310.01115","DOIUrl":"https://doi.org/arxiv-2310.01115","url":null,"abstract":"We present emergent mechanical memory storage behavior in soft cellular\u0000materials. The cellular materials are a network of soft hyperelastic rods which\u0000store shape changes, specifically local indentation. This happens under an\u0000applied global compressive strain on the material. The material transits under\u0000strain from an elastic state (capable of `forgetting' any applied indentation\u0000after un-indentation) to plastic state (indefinitely storing the shape change\u0000due to indentation). The memory can be erased via removal of applied global\u0000strains and is therefore re-programmable. We characterise this behaviour\u0000experimentally and present a simple model that makes use of friction for\u0000understanding this behavior.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"134 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523235","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}
Robert J. Cumming, Alexander G. M. Pietrow, Livia Pietrow, Maria Cavallius, Dominique Petit dit de la Roche, Casper Pietrow, Ilane Schroetter, Moa Skan
Commercial disco balls provide a safe, effective and instructive way of observing the Sun. We explore the optics of solar projections with disco balls, and find that while sunspot observations are challenging, the solar disk and its changes during eclipses are easy and fun to observe. We explore the disco ball's potential for observing the moon and other bright astronomical phenomena.
{"title":"Why every observatory needs a disco ball","authors":"Robert J. Cumming, Alexander G. M. Pietrow, Livia Pietrow, Maria Cavallius, Dominique Petit dit de la Roche, Casper Pietrow, Ilane Schroetter, Moa Skan","doi":"arxiv-2309.14173","DOIUrl":"https://doi.org/arxiv-2309.14173","url":null,"abstract":"Commercial disco balls provide a safe, effective and instructive way of\u0000observing the Sun. We explore the optics of solar projections with disco balls,\u0000and find that while sunspot observations are challenging, the solar disk and\u0000its changes during eclipses are easy and fun to observe. We explore the disco\u0000ball's potential for observing the moon and other bright astronomical\u0000phenomena.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523239","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}
We revisit the familiar scenario involving two parties in relative motion, in which Alice stays at rest while Bob goes on a journey at speed $ beta c $ along an arbitrary trajectory and reunites with Alice after a certain period of time. It is a well-known consequence of special relativity that the time that passes until they meet again is different for the two parties and is shorter in Bob's frame by a factor of $ sqrt{1-beta^2} $. We investigate how this asymmetry manifests from an information-theoretic viewpoint. Assuming that Alice and Bob transmit signals of equal average power to each other during the whole journey, and that additive white Gaussian noise is present on both sides, we show that the maximum number of bits per second that Alice can transmit reliably to Bob is always higher than the one Bob can transmit to Alice. Equivalently, the energy per bit invested by Alice is lower than that invested by Bob, meaning that the traveler is less efficient from the communication perspective, as conjectured by Jarett and Cover.
我们重新审视熟悉的两方相对运动的场景，其中Alice保持静止，而Bob沿着任意轨迹以$ beta c $的速度旅行，并在一段时间后与Alice重聚。狭义相对论的一个众所周知的结论是，在他们再次相遇之前经过的时间对双方来说是不同的，并且在鲍勃的框架中缩短了$ sqrt{1-beta^2} $倍。我们从信息论的角度研究这种不对称是如何表现的。假设Alice和Bob在整个旅程中以相等的平均功率相互传输信号，并且两边都存在加性高斯白噪声，我们证明了Alice可以可靠地传输给Bob的每秒最大比特数总是高于Bob可以传输给Alice的比特数。同样，正如贾勒特和盖伊推测的那样，爱丽丝每比特投入的能量比鲍勃投入的能量要低，这意味着从通信的角度来看，旅行者的效率更低。
{"title":"An Information-Theoretic Analog of the Twin Paradox","authors":"Mladen Kovačević, Iosif Pinelis, Marios Kountouris","doi":"arxiv-2309.11862","DOIUrl":"https://doi.org/arxiv-2309.11862","url":null,"abstract":"We revisit the familiar scenario involving two parties in relative motion, in\u0000which Alice stays at rest while Bob goes on a journey at speed $ beta c $\u0000along an arbitrary trajectory and reunites with Alice after a certain period of\u0000time. It is a well-known consequence of special relativity that the time that\u0000passes until they meet again is different for the two parties and is shorter in\u0000Bob's frame by a factor of $ sqrt{1-beta^2} $. We investigate how this\u0000asymmetry manifests from an information-theoretic viewpoint. Assuming that\u0000Alice and Bob transmit signals of equal average power to each other during the\u0000whole journey, and that additive white Gaussian noise is present on both sides,\u0000we show that the maximum number of bits per second that Alice can transmit\u0000reliably to Bob is always higher than the one Bob can transmit to Alice.\u0000Equivalently, the energy per bit invested by Alice is lower than that invested\u0000by Bob, meaning that the traveler is less efficient from the communication\u0000perspective, as conjectured by Jarett and Cover.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"600 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523051","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}
One primary reason for the formulation of the term Earth-like planet and the search for such planets in the galaxy are due to the fact that life has arisen on such a world. Thus, this search seems justifiable since it is here known what one is looking for. However, the Earth-like concept represents an attempt to set up sharp boundaries for an inhabited planet, even though nature often comes as continua. The analyzes in this work show that the term does not represent a clear cut entity as a general Earth likeness cannot be abstracted. Thus, the complex variation of environment and life means that the singular term Earth-like planet is more appropriately treated as a fuzzy world. Such a fuzzification has the consequence that the term is not only more limited than assumed, it may even be deceptive, as an Earth-like planet on the one hand can be in a segment where it does not seem particularly Earth-like, but still possesses life, but on the other hand can appear very Earth-like but not possess life anyway. An atmosphere can provide a biosignature by being displaced from thermodynamic equilibrium, derived from antagonistic adaptation, in which life as a double edged sword on the one hand continuously makes the external environment less favorable for itself, while on the other hand it increases its capacity to do so. Yet, there is an issue with using this as a search criterion for potentially inhabited worlds, as such planets can give impressions that do not reflect what has gone on, it can even give a ghost biosignature. These novel analyzes do not represent a limitation in the search for Earth-like planets, as the plethora of Earth-like planets shows the possibility that the number of inhabited worlds can be large, but it does represent a limitation in the search for life on such worlds.
{"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}
A mere amount of 2.2 grams of tritium (780 TBq), diluted in 1.25 million m$^3$ water, contained in 1047 tanks at the Fukushima Daiichi nuclear power plant are being released to the Pacific ocean. The operation is scheduled to last over 30 years, with never more than releasing 61 mg (22 TBq) of tritium annually. The outcry in the world's press and the world's population is huge and countries like China are protesting aloud and are even banning Japanese seafood being sold in their domestic market. The outcry is real, the perceived fears are real, the havoc created on the Japanese fish market is real, but the danger is non-existing. The panic results from over-regulations initiated by the International Commission on Radiological Protection (ICRP) and similar bodies world-wide, prohibiting a reliable assessment of dangers and are thereby also preventing a solid risk analysis of real dangers.
{"title":"Fukushima tritiated water release -- what is the polemic all about?","authors":"Hans Peter Beck","doi":"arxiv-2309.07083","DOIUrl":"https://doi.org/arxiv-2309.07083","url":null,"abstract":"A mere amount of 2.2 grams of tritium (780 TBq), diluted in 1.25 million\u0000m$^3$ water, contained in 1047 tanks at the Fukushima Daiichi nuclear power\u0000plant are being released to the Pacific ocean. The operation is scheduled to\u0000last over 30 years, with never more than releasing 61 mg (22 TBq) of tritium\u0000annually. The outcry in the world's press and the world's population is huge\u0000and countries like China are protesting aloud and are even banning Japanese\u0000seafood being sold in their domestic market. The outcry is real, the perceived\u0000fears are real, the havoc created on the Japanese fish market is real, but the\u0000danger is non-existing. The panic results from over-regulations initiated by\u0000the International Commission on Radiological Protection (ICRP) and similar\u0000bodies world-wide, prohibiting a reliable assessment of dangers and are thereby\u0000also preventing a solid risk analysis of real dangers.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"90 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138522943","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}
T. Marshall Eubanks W. Paul Blase Andreas Hein Adam Hibberd Robert G. Kennedy III
Interstellar communications are achievable with gram-scale spacecraft using swarm techniques introduced herein if an adequate energy source, clocks and a suitable communications protocol exist. The essence of our approach to the Breakthrough Starshot challenge is to launch a long string of 100s of gram-scale interstellar probes at 0.2c in a firing campaign up to a year long, maintain continuous contact with them (directly amongst each other and via Earth utilizing the launch laser), and gradually, during the 20-year cruise, dynamically coalesce the long string into a lens-shaped mesh network $sim$100,000 km across centered on the target planet Proxima b at the time of fly-by. In-flight formation would be accomplished using the "time on target" technique of grossly modulating the initial launch velocity between the head and the tail of the string, and combined with continual fine control or "velocity on target" by adjusting the attitude of selected probes, exploiting the drag imparted by the ISM. Such a swarm could tolerate significant attrition, e.g., by collisions enroute with interstellar dust grains, thus mitigating the risk that comes with "putting all your eggs in one basket". It would also enable the observation of Proxima b at close range from a multiplicity of viewpoints. Swarm synchronization with state-of-the-art space-rated clocks would enable operational coherence if not actual phase coherence in the swarm optical communications. Betavoltaic technology, which should be commercialized and space-rated in the next decade, can provide an adequate primary energy storage for these swarms. The combination would thus enable data return rates orders of magnitude greater than possible from a single probe.
{"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}
I apply the thermodynamics of radiation to Dyson spheres as machines that do work or computation, and examine their observational consequences. I identify four properties of Dyson spheres that complicate typical analyses: globally, they may do no work in the usual sense; they use radiation as the source and sink of energy; they accept radiation from a limited range of solid angle; and they conserve energy flux globally. I consider three kinds of activities: computation at the Landauer limit; dissipative activities, in which the energy of a sphere's activities cascades into waste heat, as for a biosphere; and "traditional" work that leaves the sphere, such as radio emission. I apply the Landsberg formalism to derive efficiency limits in all 3 cases, and show that optical circulators provide an "existence proof" that greatly simplifies the problem and allows the Landsberg limit to be plausibly approached. I find that for computation and traditional work, there is little to no advantage to nesting shells (as in a "Matrioshka Brain"); that the optimal use of mass is generally to make very small and hot Dyson spheres; that for "complete" Dyson spheres we expect optical depths of several; and that in all cases the Landsberg limit corresponds to a form of the Carnot limit. I explore how these conclusions might change in the face of complications such as the sphere having practical efficiencies below the Landsberg limit (using the endoreversible limit as an example); no use of optical circulators; and swarms of materials instead of shells.
{"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}
Violation of the Wiedemann-Franz (WF) law in a 2D topological insulator due to Majorana bound states (MBS) is studied via the Lorenz ratio in the single-particle picture. We study the scaling of the Lorenz ratio in the presence and absence of MBS with inelastic scattering modeled using a B"uttiker voltage-temperature probe. We compare our results with that seen in a quantum dot junction in the Luttinger liquid picture operating in the topological Kondo regime. We find that the scaling of the Lorenz ratio in our setup corresponds to the scaling in the Luttinger-liquid setup only when both phase and momentum relaxation occur, but not when only phase relaxation occurs. This suggests that the interplay between the presence of Majorana bound states and the type of inelastic scattering process, can have a significant impact on the violation of the Wiedemann-Franz law in 2D topological insulators.
{"title":"Majorana fermion induced power-law scaling in the violation of Wiedemann-Franz law","authors":"Ritesh Das, Colin Benjamin","doi":"arxiv-2309.05492","DOIUrl":"https://doi.org/arxiv-2309.05492","url":null,"abstract":"Violation of the Wiedemann-Franz (WF) law in a 2D topological insulator due\u0000to Majorana bound states (MBS) is studied via the Lorenz ratio in the\u0000single-particle picture. We study the scaling of the Lorenz ratio in the\u0000presence and absence of MBS with inelastic scattering modeled using a\u0000B\"uttiker voltage-temperature probe. We compare our results with that seen in\u0000a quantum dot junction in the Luttinger liquid picture operating in the\u0000topological Kondo regime. We find that the scaling of the Lorenz ratio in our\u0000setup corresponds to the scaling in the Luttinger-liquid setup only when both\u0000phase and momentum relaxation occur, but not when only phase relaxation occurs.\u0000This suggests that the interplay between the presence of Majorana bound states\u0000and the type of inelastic scattering process, can have a significant impact on\u0000the violation of the Wiedemann-Franz law in 2D topological insulators.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"136 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523232","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}
A quantum many-body state built on a classical 1D Ising model with locally entangled qubits is considered. This setup can model an infinite-player quantum Prisoner's dilemma game with each site representing two entangled players (or qubits). The local entanglement $gamma$ between two qubits placed on a site in the 1D Ising model and classical coupling between adjacent sites of the Ising model has an apposite influence on qubits. It points to a counter-intuitive situation wherein local entanglement at a site can exactly cancel global correlations, signaling an artificial quantum many-body state wherein, by locally tuning the entanglement at a particular site, one can transition from a strongly correlated quantum state to an uncorrelated quantum state and then to a correlated classical state. In other words, we can simulate a state similar to a Type II superconducting state via local tuning of entanglement in a 1D Ising chain with entangled qubits.
{"title":"Switching global correlations on and off in a many-body quantum state by tuning local entanglement","authors":"Colin Benjamin, Aditya Dash","doi":"arxiv-2309.05504","DOIUrl":"https://doi.org/arxiv-2309.05504","url":null,"abstract":"A quantum many-body state built on a classical 1D Ising model with locally\u0000entangled qubits is considered. This setup can model an infinite-player quantum\u0000Prisoner's dilemma game with each site representing two entangled players (or\u0000qubits). The local entanglement $gamma$ between two qubits placed on a site in\u0000the 1D Ising model and classical coupling between adjacent sites of the Ising\u0000model has an apposite influence on qubits. It points to a counter-intuitive\u0000situation wherein local entanglement at a site can exactly cancel global\u0000correlations, signaling an artificial quantum many-body state wherein, by\u0000locally tuning the entanglement at a particular site, one can transition from a\u0000strongly correlated quantum state to an uncorrelated quantum state and then to\u0000a correlated classical state. In other words, we can simulate a state similar\u0000to a Type II superconducting state via local tuning of entanglement in a 1D\u0000Ising chain with entangled qubits.","PeriodicalId":501348,"journal":{"name":"arXiv - PHYS - Popular Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523238","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}
Raghav NarasimhaCHRIST University, Bangalore, India, Margarita SafonovaIndian Institute of Astrophysics, Bangalore, India, C. SivaramIndian Institute of Astrophysics, Bangalore, India
In 2015, a star KIC 8462852 caught the world's attention due to a paper by citizen scientists who noticed its seemingly unexplainable brightness variations. The forward theory was offered - KIC 8462852 is surrounded by a Dyson sphere, a megastructure made by an alien civilization to collect all energy output from their star. Finally, in 2018, its light curve showed chromaticity more characteristic of the dust (from comets or asteroids) rather than of something made from solid material, but the world was woken up to the idea of megastructures. But, in Dyson's time, only Solar System planets were known; it took more than 20 years to realize that nature has no problem making planets and does it with a flair -- the total number of planets in the Galaxy is estimated to be in billions. With such abundance of planets, there would be no need to destroy the entire planetary system to make one sphere. Instead, a civilization can expand to a system that has planet(s) in the habitable zone (HZ), or a planet can be moved into it. Alternatively, a free-floating planet (FFP) can be captured and moved into the HZ. These shifts can be performed at a constant low-thrust acceleration using high power directional lasers, resulting in a gradual spiral transfer from one orbit to another. We propose here to search for ETI by looking for high-power laser technosignatures and consider merits of such signatures. We suggest to specifically pay attention to the multiple planetary systems that have Strange Exoplanetary Architectures (SEA) - unusual planetary arrangements that cannot be explained by current planetary formation theories, because these could be the result of ETI moving planets intentionally to suit their needs.
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