S ystemsmade from ordered components, such as crystals, are often laced with defects, such as dislocations, where the ordering is disrupted. Researchers have now identified a new class of such flaws where two or more dislocations come together and become locked into complex geometrical arrangements, such as coils or knots, that can’t be smoothed away [1]. Using microscopy experiments backed up by theoretical arguments, they have identified such coiled “metadefects” in thin films of liquid
{"title":"Crystal Defects Interact to Form Intricate Structures","authors":"Philip Ball","doi":"10.1103/physics.16.162","DOIUrl":"https://doi.org/10.1103/physics.16.162","url":null,"abstract":"S ystemsmade from ordered components, such as crystals, are often laced with defects, such as dislocations, where the ordering is disrupted. Researchers have now identified a new class of such flaws where two or more dislocations come together and become locked into complex geometrical arrangements, such as coils or knots, that can’t be smoothed away [1]. Using microscopy experiments backed up by theoretical arguments, they have identified such coiled “metadefects” in thin films of liquid","PeriodicalId":20136,"journal":{"name":"Physics","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136099743","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}
S ome 8 to 11 billion years ago, researchers believe the Milky Way absorbed a small dwarf galaxy, known as Gaia-Sausage-Enceladus, after the two collided. This absorption changed the structure of our Galaxy as well as its chemical makeup. The remnants of the dwarf galaxy also shaped the Milky Way’s outer halo and its centrally located “inner thick disk.” Now Ioana Ciucă of the Australian National University and her colleagues have analyzed data from nearly 70,000 stars to understand the role the merger played in subsequent stellar evolution within the inner thick disk [1]. The team finds that the stars that formed directly after the merger
{"title":"Ancient Galactic Merger Impacted Star Formation in the Milky Way","authors":"Allison Gasparini","doi":"10.1103/physics.16.161","DOIUrl":"https://doi.org/10.1103/physics.16.161","url":null,"abstract":"S ome 8 to 11 billion years ago, researchers believe the Milky Way absorbed a small dwarf galaxy, known as Gaia-Sausage-Enceladus, after the two collided. This absorption changed the structure of our Galaxy as well as its chemical makeup. The remnants of the dwarf galaxy also shaped the Milky Way’s outer halo and its centrally located “inner thick disk.” Now Ioana Ciucă of the Australian National University and her colleagues have analyzed data from nearly 70,000 stars to understand the role the merger played in subsequent stellar evolution within the inner thick disk [1]. The team finds that the stars that formed directly after the merger","PeriodicalId":20136,"journal":{"name":"Physics","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136238274","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}
V eit Elser of Cornell University has just described a new way to elucidate a problem that has baffled mathematicians for over a century: How densely can identical spheres be packed as the dimension of the spheres and of the space they occupy grow ever larger [1]? Schemes for densely packing spheres have been worked out in low dimensions and for two special cases: 8 and 24 dimensions. (A sphere in n-dimensional space is a set of points that are the same fixed distance away from a given center point.) Surprisingly, some schemes in high dimensions are little better than a random approach. What’s more, a century of research has failed to improve on the result from Hermann Minkowski, a Germanmathematician who came up with the concept of four-dimensional spacetime, that with each additional dimension, the highest fraction of space that can be occupied by spheres falls by a factor of 2. Intuitively, the rate of decrease should be slower.
{"title":"Packing Spheres in High Dimensions","authors":"Charles Day","doi":"10.1103/physics.16.s131","DOIUrl":"https://doi.org/10.1103/physics.16.s131","url":null,"abstract":"V eit Elser of Cornell University has just described a new way to elucidate a problem that has baffled mathematicians for over a century: How densely can identical spheres be packed as the dimension of the spheres and of the space they occupy grow ever larger [1]? Schemes for densely packing spheres have been worked out in low dimensions and for two special cases: 8 and 24 dimensions. (A sphere in n-dimensional space is a set of points that are the same fixed distance away from a given center point.) Surprisingly, some schemes in high dimensions are little better than a random approach. What’s more, a century of research has failed to improve on the result from Hermann Minkowski, a Germanmathematician who came up with the concept of four-dimensional spacetime, that with each additional dimension, the highest fraction of space that can be occupied by spheres falls by a factor of 2. Intuitively, the rate of decrease should be slower.","PeriodicalId":20136,"journal":{"name":"Physics","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136238275","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 he cells in our bodies, like those of all living things, encode information in so-called signaling molecules. Cells release these molecules to relay messages to other cells (for example, between neurons in the brain) and to send signals to themselves (which occurs during embryo growth). Cells also use these molecules to internally transmit information between elements of their soupy insides. The concentrations of these molecules constantly change, so researchers looking to understand a given cell-signaling process typically performmultiple measurements on the system, one after another. Now scientists at the Physics Laboratory of the École Normale Supérieure, France, show that those researchers could obtain more information from twomeasurements if they analyze them collectively, rather than sequentially [1].
{"title":"More Informative Together Than Apart","authors":"Katherine Wright","doi":"10.1103/physics.16.s138","DOIUrl":"https://doi.org/10.1103/physics.16.s138","url":null,"abstract":"T he cells in our bodies, like those of all living things, encode information in so-called signaling molecules. Cells release these molecules to relay messages to other cells (for example, between neurons in the brain) and to send signals to themselves (which occurs during embryo growth). Cells also use these molecules to internally transmit information between elements of their soupy insides. The concentrations of these molecules constantly change, so researchers looking to understand a given cell-signaling process typically performmultiple measurements on the system, one after another. Now scientists at the Physics Laboratory of the École Normale Supérieure, France, show that those researchers could obtain more information from twomeasurements if they analyze them collectively, rather than sequentially [1].","PeriodicalId":20136,"journal":{"name":"Physics","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136377474","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}
M any biological processes depend on chemical reactions that are localized in space and time and therefore require catalytic components that self-organize. The collective behavior of these active particles depends on their chemotactic movement—how they sense and respond to chemical gradients in the environment. Mixtures of such active catalysts generate complex reaction networks, and the process by which self-organization emerges in these networks presents a puzzle. Jaime Agudo-Canalejo of the Max Planck Institute for Dynamics and Self-Organization, Germany, and his colleagues now show that the phenomenon of self-organization depends strongly on the network topology [1]. The finding provides new insights for understanding microbiological systems and for engineering synthetic catalytic colloids.
{"title":"Self-Repelling Species Still Self-Organize","authors":"Rachel Berkowitz","doi":"10.1103/physics.16.s128","DOIUrl":"https://doi.org/10.1103/physics.16.s128","url":null,"abstract":"M any biological processes depend on chemical reactions that are localized in space and time and therefore require catalytic components that self-organize. The collective behavior of these active particles depends on their chemotactic movement—how they sense and respond to chemical gradients in the environment. Mixtures of such active catalysts generate complex reaction networks, and the process by which self-organization emerges in these networks presents a puzzle. Jaime Agudo-Canalejo of the Max Planck Institute for Dynamics and Self-Organization, Germany, and his colleagues now show that the phenomenon of self-organization depends strongly on the network topology [1]. The finding provides new insights for understanding microbiological systems and for engineering synthetic catalytic colloids.","PeriodicalId":20136,"journal":{"name":"Physics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135110571","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}
The Linac Coherent Light Source, an x-ray free-electron laser at SLAC National Accelerator Laboratory, lights up for the first time after an upgrade that should allow it to deliver up to one million x-ray pulses per second.
{"title":"First Light for a Next-Generation Light Source","authors":"Matteo Rini","doi":"10.1103/physics.16.160","DOIUrl":"https://doi.org/10.1103/physics.16.160","url":null,"abstract":"The Linac Coherent Light Source, an x-ray free-electron laser at SLAC National Accelerator Laboratory, lights up for the first time after an upgrade that should allow it to deliver up to one million x-ray pulses per second.","PeriodicalId":20136,"journal":{"name":"Physics","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135110572","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}
O n January 15, 2022, Earth experienced its most explosive volcanic eruption in 140 years at Hunga Tonga–Hunga Haʻapai, a partially submerged volcano in the Pacific Ocean near the Kingdom of Tonga’s main island. NowMichael Clare and Isobel Yeo of the UK’s National Oceanography Centre and their colleagues have determined the maximum speed of the underwater rock flows associated with this event [1]. Their study constitutes the most detailed investigation into the underwater aftermath of a powerful volcanic eruption and opens a new window onto a broad class of particle-laden flows.
{"title":"Breakneck Outflows from Earth’s Most Explosive Eruption","authors":"Charles Day","doi":"10.1103/physics.16.159","DOIUrl":"https://doi.org/10.1103/physics.16.159","url":null,"abstract":"O n January 15, 2022, Earth experienced its most explosive volcanic eruption in 140 years at Hunga Tonga–Hunga Haʻapai, a partially submerged volcano in the Pacific Ocean near the Kingdom of Tonga’s main island. NowMichael Clare and Isobel Yeo of the UK’s National Oceanography Centre and their colleagues have determined the maximum speed of the underwater rock flows associated with this event [1]. Their study constitutes the most detailed investigation into the underwater aftermath of a powerful volcanic eruption and opens a new window onto a broad class of particle-laden flows.","PeriodicalId":20136,"journal":{"name":"Physics","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135208306","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 he hypothesized Majorana bound state is a quasiparticle that scientists think could be a building block of a future quantum computer. It is predicted to be hosted by two quantum dots—semiconducting nanocrystals—separated by a narrow superconducting segment, but this can happen only if the processes coupling the dots are perfectly balanced. Now Tom Dvir at the Delft University of Technology in the Netherlands and his colleagues experimentally balance these processes in a hybrid semiconductor-superconductor system [1]. The experiments show no signs of a Majorana bound state, but the researchers plan to use their findings to develop a method to spot this elusive quasiparticle.
{"title":"Striking a Balance for Quantum Bits","authors":"Ryan Wilkinson","doi":"10.1103/physics.16.s124","DOIUrl":"https://doi.org/10.1103/physics.16.s124","url":null,"abstract":"T he hypothesized Majorana bound state is a quasiparticle that scientists think could be a building block of a future quantum computer. It is predicted to be hosted by two quantum dots—semiconducting nanocrystals—separated by a narrow superconducting segment, but this can happen only if the processes coupling the dots are perfectly balanced. Now Tom Dvir at the Delft University of Technology in the Netherlands and his colleagues experimentally balance these processes in a hybrid semiconductor-superconductor system [1]. The experiments show no signs of a Majorana bound state, but the researchers plan to use their findings to develop a method to spot this elusive quasiparticle.","PeriodicalId":20136,"journal":{"name":"Physics","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486510","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}
O ne of the goals of condensed-matter physicists is to catalog and explain the wide array of electronic states that can appear in materials, improving researchers’ understanding of important phenomena such as superconductivity. In recent years, experimentalists have discovered several unexpected exotic electronic states in materials called kagome superconductors, prompting intense debate over the nature of these states. Now Ilija Zeljkovic of Boston College and his colleagues have discovered features in the band structures of these materials that point toward an explanation [1].
{"title":"Experiments Support Theory for Exotic Kagome States","authors":"David Ehrenstein","doi":"10.1103/physics.16.s135","DOIUrl":"https://doi.org/10.1103/physics.16.s135","url":null,"abstract":"O ne of the goals of condensed-matter physicists is to catalog and explain the wide array of electronic states that can appear in materials, improving researchers’ understanding of important phenomena such as superconductivity. In recent years, experimentalists have discovered several unexpected exotic electronic states in materials called kagome superconductors, prompting intense debate over the nature of these states. Now Ilija Zeljkovic of Boston College and his colleagues have discovered features in the band structures of these materials that point toward an explanation [1].","PeriodicalId":20136,"journal":{"name":"Physics","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486506","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 n cell phones and other devices, a large temperature difference across a microcircuit can cause atoms to migrate, eventually resulting in faulty electrical connections. This so-called thermomigration has now been tracked at the microscale, revealing a diffusion-related force that drives the motion [1]. The researchers studied shallow depressions, or “basins,” on the surface of a square silicon wafer that was heated on one edge and cooled on the opposite edge. They
{"title":"Measuring Thermal Migration","authors":"Michael Schirber","doi":"10.1103/physics.16.157","DOIUrl":"https://doi.org/10.1103/physics.16.157","url":null,"abstract":"I n cell phones and other devices, a large temperature difference across a microcircuit can cause atoms to migrate, eventually resulting in faulty electrical connections. This so-called thermomigration has now been tracked at the microscale, revealing a diffusion-related force that drives the motion [1]. The researchers studied shallow depressions, or “basins,” on the surface of a square silicon wafer that was heated on one edge and cooled on the opposite edge. They","PeriodicalId":20136,"journal":{"name":"Physics","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486504","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}
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