Pub Date : 2025-01-01Epub Date: 2025-06-20DOI: 10.1038/s42005-025-02189-9
Elvira Bilokon, Valeriia Bilokon, Dusty R Lindberg, Lev Kaplan, Andrii Sotnikov, Denys I Bondar
Understanding quantum tunneling in many-body systems is crucial for advancing quantum technologies and nanoscale device design. Despite extensive studies of quantum tunneling, the role of interactions in determining directional transport through asymmetric barriers in discrete quantum systems remains unclear. Here we show that noninteracting fermions exhibit symmetric tunneling probabilities regardless of barrier orientation, while inter-particle interactions break this symmetry and create pronounced asymmetric tunneling behavior. We explore the dependence of tunneling behavior on the initial spin configurations of two spin-1/2 fermions: spin-triplet states preserve tunneling symmetry, while spin-singlet states show strong asymmetry. We identify regimes where interactions mediate tunneling through under-barrier resonant trapping and enhance tunneling via many-body resonant tunneling - a phenomenon arising solely from inter-particle interactions and being fundamentally different from traditional single-particle resonant tunneling. Our results may be applied to the design of nanoscale devices with tailored transport properties, such as diodes and memristors.
{"title":"Few-fermion resonant tunneling and underbarrier trapping in asymmetric potentials.","authors":"Elvira Bilokon, Valeriia Bilokon, Dusty R Lindberg, Lev Kaplan, Andrii Sotnikov, Denys I Bondar","doi":"10.1038/s42005-025-02189-9","DOIUrl":"10.1038/s42005-025-02189-9","url":null,"abstract":"<p><p>Understanding quantum tunneling in many-body systems is crucial for advancing quantum technologies and nanoscale device design. Despite extensive studies of quantum tunneling, the role of interactions in determining directional transport through asymmetric barriers in discrete quantum systems remains unclear. Here we show that noninteracting fermions exhibit symmetric tunneling probabilities regardless of barrier orientation, while inter-particle interactions break this symmetry and create pronounced asymmetric tunneling behavior. We explore the dependence of tunneling behavior on the initial spin configurations of two spin-1/2 fermions: spin-triplet states preserve tunneling symmetry, while spin-singlet states show strong asymmetry. We identify regimes where interactions mediate tunneling through under-barrier resonant trapping and enhance tunneling via many-body resonant tunneling - a phenomenon arising solely from inter-particle interactions and being fundamentally different from traditional single-particle resonant tunneling. Our results may be applied to the design of nanoscale devices with tailored transport properties, such as diodes and memristors.</p>","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":"8 1","pages":"259"},"PeriodicalIF":5.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12181076/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144474150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01Epub Date: 2025-05-28DOI: 10.1038/s42005-025-02142-w
Hongjian Wang, Alexander Hadjiivanov, Emmanuel Blazquez, Christian M Schlepütz, Marco Stampanoni, Goran Lovric
Event cameras, as novel bio-inspired neuromorphic sensors, detect per-pixel brightness changes asynchronously. Despite their growing popularity in various applications, their potential in X-ray imaging remains largely unexplored. Synchrotron-based X-ray imaging plays a significant role in various fields of science, technology and medicine. However, time-resolved imaging still faces several challenges in achieving higher sampling rates and managing the substantial data volume. Here, we introduce an inline dual-camera setup, which leverages a high-speed CMOS camera and an event camera, aiming to temporally super-resolve the sampled frame data using sparse events. To process the data, frames and events are first aligned pixel-by-pixel using feature matching, and then used to train a deep-learning neural network. This network effectively integrates the two modalities to reconstruct the intermediate frames, achieving up to a 6-fold temporal upsampling. Our work demonstrates an event-guided temporal super-resolution approach in the X-ray imaging domain, which unlocks possibilities for future time-resolved experiments.
{"title":"Event-guided temporally super-resolved synchrotron X-ray imaging.","authors":"Hongjian Wang, Alexander Hadjiivanov, Emmanuel Blazquez, Christian M Schlepütz, Marco Stampanoni, Goran Lovric","doi":"10.1038/s42005-025-02142-w","DOIUrl":"10.1038/s42005-025-02142-w","url":null,"abstract":"<p><p>Event cameras, as novel bio-inspired neuromorphic sensors, detect per-pixel brightness changes asynchronously. Despite their growing popularity in various applications, their potential in X-ray imaging remains largely unexplored. Synchrotron-based X-ray imaging plays a significant role in various fields of science, technology and medicine. However, time-resolved imaging still faces several challenges in achieving higher sampling rates and managing the substantial data volume. Here, we introduce an inline dual-camera setup, which leverages a high-speed CMOS camera and an event camera, aiming to temporally super-resolve the sampled frame data using sparse events. To process the data, frames and events are first aligned pixel-by-pixel using feature matching, and then used to train a deep-learning neural network. This network effectively integrates the two modalities to reconstruct the intermediate frames, achieving up to a 6-fold temporal upsampling. Our work demonstrates an event-guided temporal super-resolution approach in the X-ray imaging domain, which unlocks possibilities for future time-resolved experiments.</p>","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":"8 1","pages":"222"},"PeriodicalIF":5.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12119327/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01Epub Date: 2025-11-17DOI: 10.1038/s42005-025-02413-6
Hugo Pérez-Martínez, Santiago Lamata-Otín, Federico Malizia, Luis Mario Floría, Jesús Gómez-Gardeñes, David Soriano-Paños
Many social interactions are group-based, yet their role in social polarization remains largely unexplored. To bridge this gap here we introduce a higher-order framework that takes into account both group interactions and homophily. We find that group interactions can strongly enhance polarization in sparse systems by limiting agents' exposure to dissenting views. Conversely, they can suppress polarization in fully connected societies, an effect that intensifies as the group size increases. Our results highlight that polarization depends not only on the homophily strength but also on the structure and microscopic arrangement of group interactions.
{"title":"Social polarization promoted by sparse higher-order interactions.","authors":"Hugo Pérez-Martínez, Santiago Lamata-Otín, Federico Malizia, Luis Mario Floría, Jesús Gómez-Gardeñes, David Soriano-Paños","doi":"10.1038/s42005-025-02413-6","DOIUrl":"10.1038/s42005-025-02413-6","url":null,"abstract":"<p><p>Many social interactions are group-based, yet their role in social polarization remains largely unexplored. To bridge this gap here we introduce a higher-order framework that takes into account both group interactions and homophily. We find that group interactions can strongly enhance polarization in sparse systems by limiting agents' exposure to dissenting views. Conversely, they can suppress polarization in fully connected societies, an effect that intensifies as the group size increases. Our results highlight that polarization depends not only on the homophily strength but also on the structure and microscopic arrangement of group interactions.</p>","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":"8 1","pages":"507"},"PeriodicalIF":5.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12805874/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145997525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1038/s42005-024-01927-9
Ke Cheng, Meiying Hou, Wei Sun, Zhihong Qiao, Xiang Li, Chufan Lai, Jinchao Yuan, Tuo Li, Fangfu Ye, Ke Chen, Mingcheng Yang
Our experiments aboard the Chinese Space Station reveal a gravity-driven transition in intruder dynamics within vibrated granular media. While vibrations typically enable an intruder to ascend in a granular bed, low-gravity conditions induce it to descend under similar vibrations. Using a Hall-sensor array tracking method, we monitor the intruder’s movement throughout each vibration cycle and identified two competing mechanisms: inertia and gravity-dependent penetration. As gravity decreases, we observe a significant reduction in the scaled damping coefficient and hydrostatic pressure coefficient indicating that bed particles disperse more readily upon intruder impact, facilitating deeper penetration. Our findings highlight a critical transition from downward to upward motion of the intruder as vibration acceleration exceeds a threshold, which increases as gravity decreases. These insights into intruder dynamics in low-gravity environments have significant implications for asteroid exploration and lunar base construction, enhancing our understanding of the Brazil nut effect and the formation of planetesimal. Granular segregation may play a role in shaping the surface features of small celestial bodies such as asteroids that can be explained with the Brazil-nut effect. The authors study intruder dynamics in granular media on board the Chinese Space Station, finding that contrary to what occurs on Earth intruders tend to descend in microgravity conditions under specific vibration parameters
{"title":"Unraveling the role of gravity in shaping intruder dynamics within vibrated granular media","authors":"Ke Cheng, Meiying Hou, Wei Sun, Zhihong Qiao, Xiang Li, Chufan Lai, Jinchao Yuan, Tuo Li, Fangfu Ye, Ke Chen, Mingcheng Yang","doi":"10.1038/s42005-024-01927-9","DOIUrl":"10.1038/s42005-024-01927-9","url":null,"abstract":"Our experiments aboard the Chinese Space Station reveal a gravity-driven transition in intruder dynamics within vibrated granular media. While vibrations typically enable an intruder to ascend in a granular bed, low-gravity conditions induce it to descend under similar vibrations. Using a Hall-sensor array tracking method, we monitor the intruder’s movement throughout each vibration cycle and identified two competing mechanisms: inertia and gravity-dependent penetration. As gravity decreases, we observe a significant reduction in the scaled damping coefficient and hydrostatic pressure coefficient indicating that bed particles disperse more readily upon intruder impact, facilitating deeper penetration. Our findings highlight a critical transition from downward to upward motion of the intruder as vibration acceleration exceeds a threshold, which increases as gravity decreases. These insights into intruder dynamics in low-gravity environments have significant implications for asteroid exploration and lunar base construction, enhancing our understanding of the Brazil nut effect and the formation of planetesimal. Granular segregation may play a role in shaping the surface features of small celestial bodies such as asteroids that can be explained with the Brazil-nut effect. The authors study intruder dynamics in granular media on board the Chinese Space Station, finding that contrary to what occurs on Earth intruders tend to descend in microgravity conditions under specific vibration parameters","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-10"},"PeriodicalIF":5.4,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01927-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The emergence of nontrivial quantum states from competing interactions is a central issue in quantum magnetism. In particular, for the realization of the quantum spin-liquid state, extensive studies have been conducted on frustrated systems, such as kagome antiferromagnets and Kitaev magnets. Novel quantum states in magnetic fields have remained elusive despite the prediction of rich physics. This can be attributed to material scarcity and the difficulty of precise measurements under ultra-high magnetic fields. Here, in this study, we develop the Kapellasite-type compound InCu3(OH)6Cl3, whose exchange interactions are in appropriate energy scale to comprehensively elucidate the magnetic properties of the frustrated S = 1/2 kagome antiferromagnet. The one-third magnetization plateau was clearly observed. Moreover, the large temperature-linear term in the heat capacity was observed in the magnetic fields, indicating the excitation of gapless quasiparticles in the vicinity of the plateau. These results shed light on the critical behaviors between quantum spin-liquid and -solid in kagome antiferromagnets under high magnetic fields. A range of non-trivial quantum phenomena can emerge from frustrated magnetic systems and a prime example is a quantum spin liquid. Here, the authors conduct specific heat and magnetization measurements on the Kapellasite-type compound InCu3(OH)6Cl3 in order to characterize and define the range of the magnetization plateau in this material.
{"title":"One-third magnetization plateau in Quantum Kagome antiferromagnet","authors":"Moyu Kato, Yasuo Narumi, Katsuhiro Morita, Yoshitaka Matsushita, Shuhei Fukuoka, Satoshi Yamashita, Yasuhiro Nakazawa, Migaku Oda, Hiroaki Hayashi, Kazunari Yamaura, Masayuki Hagiwara, Hiroyuki K. Yoshida","doi":"10.1038/s42005-024-01922-0","DOIUrl":"10.1038/s42005-024-01922-0","url":null,"abstract":"The emergence of nontrivial quantum states from competing interactions is a central issue in quantum magnetism. In particular, for the realization of the quantum spin-liquid state, extensive studies have been conducted on frustrated systems, such as kagome antiferromagnets and Kitaev magnets. Novel quantum states in magnetic fields have remained elusive despite the prediction of rich physics. This can be attributed to material scarcity and the difficulty of precise measurements under ultra-high magnetic fields. Here, in this study, we develop the Kapellasite-type compound InCu3(OH)6Cl3, whose exchange interactions are in appropriate energy scale to comprehensively elucidate the magnetic properties of the frustrated S = 1/2 kagome antiferromagnet. The one-third magnetization plateau was clearly observed. Moreover, the large temperature-linear term in the heat capacity was observed in the magnetic fields, indicating the excitation of gapless quasiparticles in the vicinity of the plateau. These results shed light on the critical behaviors between quantum spin-liquid and -solid in kagome antiferromagnets under high magnetic fields. A range of non-trivial quantum phenomena can emerge from frustrated magnetic systems and a prime example is a quantum spin liquid. Here, the authors conduct specific heat and magnetization measurements on the Kapellasite-type compound InCu3(OH)6Cl3 in order to characterize and define the range of the magnetization plateau in this material.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-8"},"PeriodicalIF":5.4,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01922-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-27DOI: 10.1038/s42005-024-01920-2
Yue Xiao, Yongxu Peng, Linfeng Chen, Chunhui Li, Zongao Song, Xin Wang, Tao Wang, Yurun Xie, Bin Zhao, Tiangang Yang
Laser cooling typically requires one or more repump lasers to clear dark states, which complicates experimental setups, especially for systems with multiple repumping frequencies. Here, we demonstrate cooling of Be+ ions using a single laser beam, enabled by micromotion-induced one-dimensional heating. By manipulating the displacement of Be+ ions from the trap’s nodal line, we precisely control the ion micromotion velocity, eliminating the necessity of a 1.25 GHz offset repump laser while keeping ions cold in the direction perpendicular to the micromotion. We use two equivalent schemes, cooling laser detuning and ion trajectory imaging to measure the speed of the Be+ ions, with results accurately reproduced by molecular dynamics simulations based on a machine learned time-dependent electric field inside the trap. This work provides a robust method to control micromotion velocity of ions and demonstrates the potential of micromotion-assisted laser cooling to simplify setups for systems requiring multiple repumping frequencies. Reducing the number of lasers in laser cooling experiments is beneficial for simplifying systems requiring multiple repumping frequencies. This work demonstrates micromotion-assisted cooling of Be+ ions with a single laser, eliminating the need for a 1.25 GHz offset repump laser, with results rigorously validated through molecular dynamics simulations.
{"title":"Two-dimensional cooling without repump laser beams through ion motional heating","authors":"Yue Xiao, Yongxu Peng, Linfeng Chen, Chunhui Li, Zongao Song, Xin Wang, Tao Wang, Yurun Xie, Bin Zhao, Tiangang Yang","doi":"10.1038/s42005-024-01920-2","DOIUrl":"10.1038/s42005-024-01920-2","url":null,"abstract":"Laser cooling typically requires one or more repump lasers to clear dark states, which complicates experimental setups, especially for systems with multiple repumping frequencies. Here, we demonstrate cooling of Be+ ions using a single laser beam, enabled by micromotion-induced one-dimensional heating. By manipulating the displacement of Be+ ions from the trap’s nodal line, we precisely control the ion micromotion velocity, eliminating the necessity of a 1.25 GHz offset repump laser while keeping ions cold in the direction perpendicular to the micromotion. We use two equivalent schemes, cooling laser detuning and ion trajectory imaging to measure the speed of the Be+ ions, with results accurately reproduced by molecular dynamics simulations based on a machine learned time-dependent electric field inside the trap. This work provides a robust method to control micromotion velocity of ions and demonstrates the potential of micromotion-assisted laser cooling to simplify setups for systems requiring multiple repumping frequencies. Reducing the number of lasers in laser cooling experiments is beneficial for simplifying systems requiring multiple repumping frequencies. This work demonstrates micromotion-assisted cooling of Be+ ions with a single laser, eliminating the need for a 1.25 GHz offset repump laser, with results rigorously validated through molecular dynamics simulations.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-8"},"PeriodicalIF":5.4,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01920-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-26DOI: 10.1038/s42005-024-01896-z
The DarkSide-20k Collaboration
The dual-phase liquid argon time projection chamber is presently one of the leading technologies to search for dark matter particles with masses below 10 GeV c−2. This was demonstrated by the DarkSide-50 experiment with approximately 50 kg of low-radioactivity liquid argon as target material. The next generation experiment DarkSide-20k, currently under construction, will use 1,000 times more argon and is expected to start operation in 2027. Based on the DarkSide-50 experience, here we assess the DarkSide-20k sensitivity to models predicting light dark matter particles, including Weakly Interacting Massive Particles (WIMPs) and sub-GeV c−2 particles interacting with electrons in argon atoms. With one year of data, a sensitivity improvement to dark matter interaction cross-sections by at least one order of magnitude with respect to DarkSide-50 is expected for all these models. A sensitivity to WIMP–nucleon interaction cross-sections below 1 × 10−42 cm2 is achievable for WIMP masses above 800 MeV c−2. With 10 years exposure, the neutrino fog can be reached for WIMP masses around 5 GeV c−2. The DarkSide-20k collaboration reports the sensitivity of its detector, currently under construction, to models predicting light dark matter particles. This includes Weakly Interacting Massive Particles and particles interacting with bound electrons of argon atoms.
{"title":"DarkSide-20k sensitivity to light dark matter particles","authors":"The DarkSide-20k Collaboration","doi":"10.1038/s42005-024-01896-z","DOIUrl":"10.1038/s42005-024-01896-z","url":null,"abstract":"The dual-phase liquid argon time projection chamber is presently one of the leading technologies to search for dark matter particles with masses below 10 GeV c−2. This was demonstrated by the DarkSide-50 experiment with approximately 50 kg of low-radioactivity liquid argon as target material. The next generation experiment DarkSide-20k, currently under construction, will use 1,000 times more argon and is expected to start operation in 2027. Based on the DarkSide-50 experience, here we assess the DarkSide-20k sensitivity to models predicting light dark matter particles, including Weakly Interacting Massive Particles (WIMPs) and sub-GeV c−2 particles interacting with electrons in argon atoms. With one year of data, a sensitivity improvement to dark matter interaction cross-sections by at least one order of magnitude with respect to DarkSide-50 is expected for all these models. A sensitivity to WIMP–nucleon interaction cross-sections below 1 × 10−42 cm2 is achievable for WIMP masses above 800 MeV c−2. With 10 years exposure, the neutrino fog can be reached for WIMP masses around 5 GeV c−2. The DarkSide-20k collaboration reports the sensitivity of its detector, currently under construction, to models predicting light dark matter particles. This includes Weakly Interacting Massive Particles and particles interacting with bound electrons of argon atoms.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-9"},"PeriodicalIF":5.4,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01896-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-24DOI: 10.1038/s42005-024-01909-x
Riccardo Gallotti, Davide Maniscalco, Marc Barthelemy, Manlio De Domenico
The description of human mobility is at the core of many fundamental applications ranging from urbanism and transportation to epidemics containment. Data about human movements, once scarce, is now widely available thanks to new sources such as phone call detail records, GPS devices, or Smartphone apps. Nevertheless, it is still common to rely on a single dataset by implicitly assuming that the statistical properties observed are robust regardless of data gathering and processing techniques. Here, we test this assumption on a broad scale by comparing human mobility datasets obtained from 7 different data-sources, tracing 500+ millions individuals in 145 countries. We report wide quantifiable differences in the resulting mobility networks and in the displacement distribution. These variations impact processes taking place on these networks like epidemic spreading. Our results point to the need for disclosing the data processing and, overall, to follow good practices to ensure robust and reproducible results. Human mobility data is crucial for many applications, but researchers often rely on single datasets assuming universal validity. Comparing 7 diverse sources across 145 countries, we find significant differences in mobility patterns and networks, impacting applications like epidemic modeling and emphasizing the need for transparent data processing.
{"title":"Distorted insights from human mobility data","authors":"Riccardo Gallotti, Davide Maniscalco, Marc Barthelemy, Manlio De Domenico","doi":"10.1038/s42005-024-01909-x","DOIUrl":"10.1038/s42005-024-01909-x","url":null,"abstract":"The description of human mobility is at the core of many fundamental applications ranging from urbanism and transportation to epidemics containment. Data about human movements, once scarce, is now widely available thanks to new sources such as phone call detail records, GPS devices, or Smartphone apps. Nevertheless, it is still common to rely on a single dataset by implicitly assuming that the statistical properties observed are robust regardless of data gathering and processing techniques. Here, we test this assumption on a broad scale by comparing human mobility datasets obtained from 7 different data-sources, tracing 500+ millions individuals in 145 countries. We report wide quantifiable differences in the resulting mobility networks and in the displacement distribution. These variations impact processes taking place on these networks like epidemic spreading. Our results point to the need for disclosing the data processing and, overall, to follow good practices to ensure robust and reproducible results. Human mobility data is crucial for many applications, but researchers often rely on single datasets assuming universal validity. Comparing 7 diverse sources across 145 countries, we find significant differences in mobility patterns and networks, impacting applications like epidemic modeling and emphasizing the need for transparent data processing.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-10"},"PeriodicalIF":5.4,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01909-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-23DOI: 10.1038/s42005-024-01915-z
Junsheng Hou, Dongyu Li, Lei Huang, Li Ma, Xiong Zhao, Jinjia Wei, Nanjing Hao
Contactless acoustics provide a unique, flexible active means for phase-change heat transfer enhancement. However, the ultrasonic transducers used for conventional acoustic enhancement are bulky and unfavorable for integration, and the heat accumulation under high power is not conducive to long-term operation, with limited enhancement in the critical heat flux (CHF). Herein, an acoustic-enabled low-power compact heat exchanger (ALCHE) is proposed with low energy consumption and long operation duration. Based on image processing and bubble tracking algorithm, it is found that the acoustic field accelerates bubble detachment and migration for achieving superior heat flux and larger heat transfer coefficient (HTC). 1.5 kHz acoustic field performs better heat transfer performance due to its strong acoustic radiation force magnitude and excellent acoustic pressure field direction. The stronger acoustic radiation force from higher acoustic power promotes the heat transfer performance among different acoustic powers. Long-time stable operation of acoustic field enhanced heat transfer under high heat flux is achieved with low acoustic power. Our designed heat exchanger not only overcomes the limitation of traditional bulky transducers, but also provides insights into the acoustic-enabled flow boiling heat transfer process. Improving the cooling performance of high-power electronics in confined spaces remains a challenge. Herein, the authors propose an acoustic-enabled low-power compact heat exchanger that utilizes contactless acoustics as a flexible active means for enhancing phase change cooling.
{"title":"Electronic cooling via acoustic-enabled low-power compact heat exchanger","authors":"Junsheng Hou, Dongyu Li, Lei Huang, Li Ma, Xiong Zhao, Jinjia Wei, Nanjing Hao","doi":"10.1038/s42005-024-01915-z","DOIUrl":"10.1038/s42005-024-01915-z","url":null,"abstract":"Contactless acoustics provide a unique, flexible active means for phase-change heat transfer enhancement. However, the ultrasonic transducers used for conventional acoustic enhancement are bulky and unfavorable for integration, and the heat accumulation under high power is not conducive to long-term operation, with limited enhancement in the critical heat flux (CHF). Herein, an acoustic-enabled low-power compact heat exchanger (ALCHE) is proposed with low energy consumption and long operation duration. Based on image processing and bubble tracking algorithm, it is found that the acoustic field accelerates bubble detachment and migration for achieving superior heat flux and larger heat transfer coefficient (HTC). 1.5 kHz acoustic field performs better heat transfer performance due to its strong acoustic radiation force magnitude and excellent acoustic pressure field direction. The stronger acoustic radiation force from higher acoustic power promotes the heat transfer performance among different acoustic powers. Long-time stable operation of acoustic field enhanced heat transfer under high heat flux is achieved with low acoustic power. Our designed heat exchanger not only overcomes the limitation of traditional bulky transducers, but also provides insights into the acoustic-enabled flow boiling heat transfer process. Improving the cooling performance of high-power electronics in confined spaces remains a challenge. Herein, the authors propose an acoustic-enabled low-power compact heat exchanger that utilizes contactless acoustics as a flexible active means for enhancing phase change cooling.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-9"},"PeriodicalIF":5.4,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01915-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142870536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anomalous Floquet topological phases are unique to periodically driven systems, lacking a static analog. Inspired by Floquet Engineering with classical electromagnetic radiation, Quantum Floquet Engineering has emerged as a promising tool to tailor the properties of quantum materials using quantum light. While the latter recovers the physics of Floquet materials in its semi-classical limit, the mapping between these two scenarios remains mysterious in many aspects. In this work, we discuss the emergence of quantum anomalous topological phases in cavity-QED materials, linking the topological phase transitions in the electron-photon spectrum with those in the 0- and π-gaps of Floquet quasienergies. Our results establish the microscopic origin of an emergent discrete time-translation symmetry in the matter sector, and link isolated c-QED materials with periodically driven ones. Finally, we discuss the bulk-edge correspondence in terms of hybrid light-matter topological invariants. Non-equilibrium systems subject to periodic driving fields, known as Floquet materials, can host unique topological phases without static counterpart. This work targets the link between Floquet physics and cavity-QED systems, and unveils the emergence of quantum anomalous phases in the latter, pointing to the important entangled light-matter dynamics.
{"title":"Quantum origin of anomalous Floquet phases in cavity-QED materials","authors":"Beatriz Pérez-González, Gloria Platero, Álvaro Gómez-León","doi":"10.1038/s42005-024-01908-y","DOIUrl":"10.1038/s42005-024-01908-y","url":null,"abstract":"Anomalous Floquet topological phases are unique to periodically driven systems, lacking a static analog. Inspired by Floquet Engineering with classical electromagnetic radiation, Quantum Floquet Engineering has emerged as a promising tool to tailor the properties of quantum materials using quantum light. While the latter recovers the physics of Floquet materials in its semi-classical limit, the mapping between these two scenarios remains mysterious in many aspects. In this work, we discuss the emergence of quantum anomalous topological phases in cavity-QED materials, linking the topological phase transitions in the electron-photon spectrum with those in the 0- and π-gaps of Floquet quasienergies. Our results establish the microscopic origin of an emergent discrete time-translation symmetry in the matter sector, and link isolated c-QED materials with periodically driven ones. Finally, we discuss the bulk-edge correspondence in terms of hybrid light-matter topological invariants. Non-equilibrium systems subject to periodic driving fields, known as Floquet materials, can host unique topological phases without static counterpart. This work targets the link between Floquet physics and cavity-QED systems, and unveils the emergence of quantum anomalous phases in the latter, pointing to the important entangled light-matter dynamics.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-9"},"PeriodicalIF":5.4,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01908-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142862433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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