Pub Date : 2024-11-07DOI: 10.1016/j.physrep.2024.10.005
Stephan Rachel , Roland Wiesendanger
For the past decade, Majorana quasiparticles have become one of the hot topics in condensed matter research. Besides the fundamental interest in the realization of particles being their own antiparticles, going back to basic concepts of elementary particle physics, Majorana quasiparticles in condensed matter systems offer exciting potential applications in topological quantum computation due to their non-Abelian quantum exchange statistics. Motivated by theoretical predictions about possible realizations of Majorana quasiparticles as zero-energy modes at boundaries of topological superconductors, experimental efforts have focussed in particular on quasi-one-dimensional semiconductor–superconductor and magnet–superconductor hybrid systems. However, an unambiguous proof of the existence of Majorana quasiparticles is still challenging and requires considerable improvements in materials science, atomic-scale characterization and control of interface quality, as well as complementary approaches of detecting various facets of Majorana quasiparticles. Bottom-up atom-by-atom fabrication of disorder-free atomic spin chains on atomically clean superconducting substrates has recently allowed deep insight into the emergence of topological sub-gap Shiba bands and associated Majorana states from the level of individual atoms up to extended chains, thereby offering the possibility for critical tests of Majorana physics in disorder-free model-type 1D hybrid systems.
{"title":"Majorana quasiparticles in atomic spin chains on superconductors","authors":"Stephan Rachel , Roland Wiesendanger","doi":"10.1016/j.physrep.2024.10.005","DOIUrl":"10.1016/j.physrep.2024.10.005","url":null,"abstract":"<div><div>For the past decade, Majorana quasiparticles have become one of the hot topics in condensed matter research. Besides the fundamental interest in the realization of particles being their own antiparticles, going back to basic concepts of elementary particle physics, Majorana quasiparticles in condensed matter systems offer exciting potential applications in topological quantum computation due to their non-Abelian quantum exchange statistics. Motivated by theoretical predictions about possible realizations of Majorana quasiparticles as zero-energy modes at boundaries of topological superconductors, experimental efforts have focussed in particular on quasi-one-dimensional semiconductor–superconductor and magnet–superconductor hybrid systems. However, an unambiguous proof of the existence of Majorana quasiparticles is still challenging and requires considerable improvements in materials science, atomic-scale characterization and control of interface quality, as well as complementary approaches of detecting various facets of Majorana quasiparticles. Bottom-up atom-by-atom fabrication of disorder-free atomic spin chains on atomically clean superconducting substrates has recently allowed deep insight into the emergence of topological sub-gap Shiba bands and associated Majorana states from the level of individual atoms up to extended chains, thereby offering the possibility for critical tests of Majorana physics in disorder-free model-type 1D hybrid systems.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1099 ","pages":"Pages 1-28"},"PeriodicalIF":23.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658262","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 : 2024-11-07DOI: 10.1016/j.physrep.2024.10.004
J. Heckötter , A. Farenbruch , D. Fröhlich , M. Aßmann , D.R. Yakovlev , M. Bayer , M.A. Semina , M.M. Glazov , P. Rommel , J. Ertl , J. Main , H. Stolz
This article discusses the experimental status achieved in the assessment of the hydrogen-like series of Wannier–Mott excitons, using the semiconductor cuprous oxide, CuO, as material platform. While for other crystals the observed exciton series are limited to low principal quantum numbers and typically a particular orbital angular momentum , recently a major extension of the number of detected states has been achieved for the so-called yellow exciton series in cuprous oxide. About 60 quantum number combinations , defining different shells of possible exciton states, were detected in high-resolution one-photon absorption and second harmonic generation spectroscopy, also complemented with application of external electric or magnetic fields. The extension concerns not only the optically active states (the orthoexcitons) that are allowed in different orders of light–matter coupling, but also the states that are optically forbidden due to spin conservation in optical transitions (the paraexcitons). The hydrogen model provides a good overall description of the exciton level spectrum. However, an analysis with sufficient energy resolution reveals significant deviations evidenced by shell splittings, which arise from breaking of the rotational into discrete symmetries in the cubic crystal environment. The resulting fine structure splitting between different shells and within a shell is mainly determined by the valence band dispersion in CuO showing pronounced band mixing effects. The corresponding extensions in the exciton Hamiltonian bear similarity to those causing the fine structure splitting in hydrogen, namely a higher order kinetic energy term and a spin–orbit coupling term. In addition, the electron–hole exchange interaction arising for the orthoexcitons and corrections to the dielectric screening provide further contributions to the fine structure splitting. As a consequence, the hydrogen wavefunctions are valid only approximately for describing excitons, being in fact coupled in the exciton envelopes. Despite the broken -degeneracy of the exciton levels, further symmetry protected degeneracies remain, which can be removed by applying external fields. We describe the evolution of the fine structure spectrum in electric and magnetic fields towards Stark ladders and Landau fans, respectively. The optical spectra depend on the crystal orientation relative to the external field in addition to their dependence on the chosen optical axis. Also, the deviations from an isotropic medium become obvious, as the symm
本文讨论了以半导体氧化亚铜（Cu2O）为材料平台，在评估类氢系列万尼尔-莫特激子方面所取得的实验成果。对其他晶体而言，所观测到的激子系列仅限于低主量子数 n 和典型的特定轨道角动量 L，而最近对氧化亚铜中所谓的黄色激子系列而言，所检测到的状态数量有了重大扩展。在高分辨率单光子吸收和二次谐波发生光谱中检测到了约 60 种量子数组合 (n,L)，这些量子数组合定义了可能的激子状态的不同外壳，同时还辅以外部电场或磁场。这一扩展不仅涉及在不同光-物质耦合阶数下允许存在的光学活性状态（正激子），还涉及由于光学转换中的自旋守恒而被光学禁止的状态（副激子）。氢模型能很好地全面描述激子水平谱。然而，在进行具有足够能量分辨率的分析时，会发现由于立方晶体环境中的旋转离散对称性被打破而产生的壳分裂（shell splittings）所证明的重大偏差。由此产生的不同壳之间以及一个壳（n,L）内的精细结构分裂主要由 Cu2O 中的价带色散决定，显示出明显的带混合效应。激子哈密顿中的相应扩展与氢中导致精细结构分裂的扩展相似，即高阶动能项和自旋轨道耦合项。此外，正交激子产生的电子-空穴交换相互作用和介电屏蔽修正也对精细结构分裂做出了进一步的贡献。因此，氢波函数仅对描述激子近似有效，实际上在激子包络中是耦合的。尽管激子水平的 L 退化被打破，但仍存在进一步的对称保护退化，这些退化可以通过施加外部场来消除。我们描述了精细结构光谱在电场和磁场中分别向斯塔克梯形和朗道扇形演变的过程。除了与所选光轴有关之外，光学光谱还取决于晶体相对于外部磁场的取向。此外，与各向同性介质的偏差也变得非常明显，因为对称性降低和由此产生的状态耦合会导致避免在水平进入场致共振时发生交叉。在所有对称性都被打破的情况下施加场，在主量子数超过 n=5 的状态范围内观察到量子混沌，在状态共振处观察到的完全是反交叉就证明了这一点。数据概要表明，高分辨率激子光谱学已达到接近原子系统的精确水平。
{"title":"The energy level spectrum of the yellow excitons in cuprous oxide","authors":"J. Heckötter , A. Farenbruch , D. Fröhlich , M. Aßmann , D.R. Yakovlev , M. Bayer , M.A. Semina , M.M. Glazov , P. Rommel , J. Ertl , J. Main , H. Stolz","doi":"10.1016/j.physrep.2024.10.004","DOIUrl":"10.1016/j.physrep.2024.10.004","url":null,"abstract":"<div><div>This article discusses the experimental status achieved in the assessment of the hydrogen-like series of Wannier–Mott excitons, using the semiconductor cuprous oxide, Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O, as material platform. While for other crystals the observed exciton series are limited to low principal quantum numbers <span><math><mi>n</mi></math></span> and typically a particular orbital angular momentum <span><math><mi>L</mi></math></span>, recently a major extension of the number of detected states has been achieved for the so-called yellow exciton series in cuprous oxide. About 60 quantum number combinations <span><math><mrow><mo>(</mo><mi>n</mi><mo>,</mo><mi>L</mi><mo>)</mo></mrow></math></span>, defining different shells of possible exciton states, were detected in high-resolution one-photon absorption and second harmonic generation spectroscopy, also complemented with application of external electric or magnetic fields. The extension concerns not only the optically active states (the orthoexcitons) that are allowed in different orders of light–matter coupling, but also the states that are optically forbidden due to spin conservation in optical transitions (the paraexcitons). The hydrogen model provides a good overall description of the exciton level spectrum. However, an analysis with sufficient energy resolution reveals significant deviations evidenced by shell splittings, which arise from breaking of the rotational into discrete symmetries in the cubic crystal environment. The resulting fine structure splitting between different shells and within a shell <span><math><mrow><mo>(</mo><mi>n</mi><mo>,</mo><mi>L</mi><mo>)</mo></mrow></math></span> is mainly determined by the valence band dispersion in Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O showing pronounced band mixing effects. The corresponding extensions in the exciton Hamiltonian bear similarity to those causing the fine structure splitting in hydrogen, namely a higher order kinetic energy term and a spin–orbit coupling term. In addition, the electron–hole exchange interaction arising for the orthoexcitons and corrections to the dielectric screening provide further contributions to the fine structure splitting. As a consequence, the hydrogen wavefunctions are valid only approximately for describing excitons, being in fact coupled in the exciton envelopes. Despite the broken <span><math><mi>L</mi></math></span>-degeneracy of the exciton levels, further symmetry protected degeneracies remain, which can be removed by applying external fields. We describe the evolution of the fine structure spectrum in electric and magnetic fields towards Stark ladders and Landau fans, respectively. The optical spectra depend on the crystal orientation relative to the external field in addition to their dependence on the chosen optical axis. Also, the deviations from an isotropic medium become obvious, as the symm","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1100 ","pages":"Pages 1-69"},"PeriodicalIF":23.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659335","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 : 2024-11-07DOI: 10.1016/j.physrep.2024.10.006
Li Feng , Dengcheng Yang , Sinan Wu , Chengwen Xue , Mengmeng Sang , Xiang Liu , Jincan Che , Jie Wu , Claudia Gragnoli , Christopher Griffin , Chen Wang , Shing-Tung Yau , Rongling Wu
Aging is a universal process of age-dependent physiological and functional declines that are strongly associated with human diseases. Despite extensive studies of the molecular causes of aging, little is known about the overall landscape of how aging proceeds and how it is related with intrinsic and extrinsic agents. Aging is a complex trait involving a large number of interdependent factors that change over spatiotemporal scales like a complex system. We develop an interdisciplinary form of statistical mechanics to reconstruct aging-related informative, dynamic, omnidirectional, and personalized networks (idopNetworks) from experimental or clinical data. The idopNetwork model can reveal how a specific biological entity, such as genes, proteins, or metabolites, mediates the antedependence of aging (i.e., the dependence of current trait values on their previous expression), identify how spatiotemporal crosstalk across different organs accelerate or decelerate the rate of aging, and predict how an individual’s chronological age differs from his biological age. We implement GLMY homology theory to dissect the topological architecture and function of aging networks, identifying key subnetworks, surface holes and cubic voids that shape the rate of aging. Aging studies can be ideally conducted by monitoring molecular, physiological, and clinical traits over the full lifecycle. However, it is both impossible and ethically impermissible to collect the kind of data from which idopNetworks are reconstructed. To overcome this limitation, we integrate an allometric scaling law into the model to extract dynamics from snapshots of static data from a population-based cross-sectional study, expanding the utility of the model to a broader domain of cohort data. We show how this model can be used to unravel and predict the biological mechanisms underlying aging by analyzing an experimental metabolic data set of multiple brain regions in the aging mouse and a cross-sectional physiological data set of the lung for smoking and nonsmoking males aged from 20 years to nearly centenarians from the China Pulmonary Health Study. The model opens up a new horizon for studying how aging occurs through intrinsic and extrinsic interactions and could be used as a generic tool to disentangle human aging using various types of molecular, phenotypic or clinical data.
{"title":"Network modeling and topology of aging","authors":"Li Feng , Dengcheng Yang , Sinan Wu , Chengwen Xue , Mengmeng Sang , Xiang Liu , Jincan Che , Jie Wu , Claudia Gragnoli , Christopher Griffin , Chen Wang , Shing-Tung Yau , Rongling Wu","doi":"10.1016/j.physrep.2024.10.006","DOIUrl":"10.1016/j.physrep.2024.10.006","url":null,"abstract":"<div><div>Aging is a universal process of age-dependent physiological and functional declines that are strongly associated with human diseases. Despite extensive studies of the molecular causes of aging, little is known about the overall landscape of how aging proceeds and how it is related with intrinsic and extrinsic agents. Aging is a complex trait involving a large number of interdependent factors that change over spatiotemporal scales like a complex system. We develop an interdisciplinary form of statistical mechanics to reconstruct aging-related informative, dynamic, omnidirectional, and personalized networks (idopNetworks) from experimental or clinical data. The idopNetwork model can reveal how a specific biological entity, such as genes, proteins, or metabolites, mediates the antedependence of aging (i.e., the dependence of current trait values on their previous expression), identify how spatiotemporal crosstalk across different organs accelerate or decelerate the rate of aging, and predict how an individual’s chronological age differs from his biological age. We implement GLMY homology theory to dissect the topological architecture and function of aging networks, identifying key subnetworks, surface holes and cubic voids that shape the rate of aging. Aging studies can be ideally conducted by monitoring molecular, physiological, and clinical traits over the full lifecycle. However, it is both impossible and ethically impermissible to collect the kind of data from which idopNetworks are reconstructed. To overcome this limitation, we integrate an allometric scaling law into the model to extract dynamics from snapshots of static data from a population-based cross-sectional study, expanding the utility of the model to a broader domain of cohort data. We show how this model can be used to unravel and predict the biological mechanisms underlying aging by analyzing an experimental metabolic data set of multiple brain regions in the aging mouse and a cross-sectional physiological data set of the lung for smoking and nonsmoking males aged from 20 years to nearly centenarians from the China Pulmonary Health Study. The model opens up a new horizon for studying how aging occurs through intrinsic and extrinsic interactions and could be used as a generic tool to disentangle human aging using various types of molecular, phenotypic or clinical data.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1101 ","pages":"Pages 1-65"},"PeriodicalIF":23.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantum correlation and quantum measurement are core issues in understanding the quantum world. Revealing quantum correlations in microphysical systems through proper quantum measurements became an important research topic in the last century and gave rise to the birth of quantum information technologies. However, quantum correlations, quantum measurements, and their relationship are not yet fully understood and require further clarification. The development of generalized quantum measurement and non-destructive measurement provides new possibilities for studying these issues. In the past decade, a series of studies on quantum correlation sharing through sequential generalized measurements have unveiled a new avenue for exploring quantum correlations. These studies not only have important fundamental significance, but also involve the unexplored issue of quantum resource recycling. This review thoroughly examines recent advancements in quantum correlation sharing. It begins by elucidating the fundamental reasons for quantum correlation sharing based on the interpretation of joint probabilities, and discussing the basic definitions and concepts. Next, the sharing of Bell nonlocality under different measurement strategies and scenarios is carefully examined, especially pointing out the impact of these strategies on the maximum number of parties that can exhibit Bell nonlocality. The subsequent chapters provide an overview of other forms of quantum correlation sharing, including quantum steering, network nonlocality, quantum entanglement, and quantum contextuality. Furthermore, we summarize the advancements in the application of quantum correlation sharing across various quantum tasks, highlighting examples such as quantum random access codes, random number generation, and self-testing tasks. Finally, we discuss and enumerate some key unresolved issues in this research area, concluding this review.
{"title":"A review of quantum correlation sharing: The recycling of quantum correlations triggered by quantum measurements","authors":"Zinuo Cai , Changliang Ren , Tianfeng Feng , Xiaoqi Zhou , Jingling Chen","doi":"10.1016/j.physrep.2024.10.003","DOIUrl":"10.1016/j.physrep.2024.10.003","url":null,"abstract":"<div><div>Quantum correlation and quantum measurement are core issues in understanding the quantum world. Revealing quantum correlations in microphysical systems through proper quantum measurements became an important research topic in the last century and gave rise to the birth of quantum information technologies. However, quantum correlations, quantum measurements, and their relationship are not yet fully understood and require further clarification. The development of generalized quantum measurement and non-destructive measurement provides new possibilities for studying these issues. In the past decade, a series of studies on quantum correlation sharing through sequential generalized measurements have unveiled a new avenue for exploring quantum correlations. These studies not only have important fundamental significance, but also involve the unexplored issue of quantum resource recycling. This review thoroughly examines recent advancements in quantum correlation sharing. It begins by elucidating the fundamental reasons for quantum correlation sharing based on the interpretation of joint probabilities, and discussing the basic definitions and concepts. Next, the sharing of Bell nonlocality under different measurement strategies and scenarios is carefully examined, especially pointing out the impact of these strategies on the maximum number of parties that can exhibit Bell nonlocality. The subsequent chapters provide an overview of other forms of quantum correlation sharing, including quantum steering, network nonlocality, quantum entanglement, and quantum contextuality. Furthermore, we summarize the advancements in the application of quantum correlation sharing across various quantum tasks, highlighting examples such as quantum random access codes, random number generation, and self-testing tasks. Finally, we discuss and enumerate some key unresolved issues in this research area, concluding this review.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1098 ","pages":"Pages 1-53"},"PeriodicalIF":23.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.physrep.2024.09.014
Daniel Cebrián-Lacasa , Pedro Parra-Rivas , Daniel Ruiz-Reynés , Lendert Gelens
The FitzHugh–Nagumo equation, originally conceived in neuroscience during the 1960s, became a key model providing a simplified view of excitable neuron cell behavior. Its applicability, however, extends beyond neuroscience into fields like cardiac physiology, cell division, population dynamics, electronics, and other natural phenomena. In this review spanning six decades of research, we discuss the diverse spatio-temporal dynamical behaviors described by the FitzHugh–Nagumo equation. These include dynamics like bistability, oscillations, and excitability, but it also addresses more complex phenomena such as traveling waves and extended patterns in coupled systems. The review serves as a guide for modelers aiming to utilize the strengths of the FitzHugh–Nagumo model to capture generic dynamical behavior. It not only catalogs known dynamical states and bifurcations, but also extends previous studies by providing stability and bifurcation analyses for coupled spatial systems.
{"title":"Six decades of the FitzHugh–Nagumo model: A guide through its spatio-temporal dynamics and influence across disciplines","authors":"Daniel Cebrián-Lacasa , Pedro Parra-Rivas , Daniel Ruiz-Reynés , Lendert Gelens","doi":"10.1016/j.physrep.2024.09.014","DOIUrl":"10.1016/j.physrep.2024.09.014","url":null,"abstract":"<div><div>The FitzHugh–Nagumo equation, originally conceived in neuroscience during the 1960s, became a key model providing a simplified view of excitable neuron cell behavior. Its applicability, however, extends beyond neuroscience into fields like cardiac physiology, cell division, population dynamics, electronics, and other natural phenomena. In this review spanning six decades of research, we discuss the diverse spatio-temporal dynamical behaviors described by the FitzHugh–Nagumo equation. These include dynamics like bistability, oscillations, and excitability, but it also addresses more complex phenomena such as traveling waves and extended patterns in coupled systems. The review serves as a guide for modelers aiming to utilize the strengths of the FitzHugh–Nagumo model to capture generic dynamical behavior. It not only catalogs known dynamical states and bifurcations, but also extends previous studies by providing stability and bifurcation analyses for coupled spatial systems.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1096 ","pages":"Pages 1-39"},"PeriodicalIF":23.9,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142539561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.physrep.2024.10.002
R. Bailhache , D. Bonocore , P. Braun-Munzinger , X. Feal , S. Floerchinger , J. Klein , K. Köhler , P. Lebiedowicz , C.M. Peter , R. Rapp , K. Reygers , W. Schäfer , H.S. Scheid , K. Schweda , J. Stachel , H. van Hees , C.A. van Veen , M. Völkl
This report summarizes the work of the EMMI Rapid Reaction Task Force on “Real and Virtual Photon Production at Ultra-Low Transverse Momentum and Low Mass at the LHC”. We provide an overview of the soft-photon puzzle, i.e., of the long-standing discrepancy between experimental data and predictions based on Low’s soft-photon theorem, also referred to as “anomalous” soft photon production, and we review the current theoretical understanding of soft radiation and soft theorems. We also focus on low-mass dileptons as a tool for determining the electrical conductivity of the medium produced in high-energy nucleus–nucleus collisions. We discuss how both topics can be addressed with the planned ALICE 3 detector at the LHC.
本报告总结了欧洲粒子监测中心 "大型强子对撞机超低横动量和低质量下的真实和虚拟光子产生 "快速反应工作组的工作。我们概述了软光子之谜，即实验数据与基于洛氏软光子定理（也称为 "反常 "软光子产生）的预测之间长期存在的差异，并回顾了当前对软辐射和软定理的理论理解。我们还关注低质量二价子，将其作为确定高能核-核碰撞中产生的介质导电性的工具。我们将讨论如何利用计划中的大型强子对撞机 ALICE 3 探测器来解决这两个问题。
{"title":"Anomalous soft photons: Status and perspectives","authors":"R. Bailhache , D. Bonocore , P. Braun-Munzinger , X. Feal , S. Floerchinger , J. Klein , K. Köhler , P. Lebiedowicz , C.M. Peter , R. Rapp , K. Reygers , W. Schäfer , H.S. Scheid , K. Schweda , J. Stachel , H. van Hees , C.A. van Veen , M. Völkl","doi":"10.1016/j.physrep.2024.10.002","DOIUrl":"10.1016/j.physrep.2024.10.002","url":null,"abstract":"<div><div>This report summarizes the work of the EMMI Rapid Reaction Task Force on “Real and Virtual Photon Production at Ultra-Low Transverse Momentum and Low Mass at the LHC”. We provide an overview of the soft-photon puzzle, i.e., of the long-standing discrepancy between experimental data and predictions based on Low’s soft-photon theorem, also referred to as “anomalous” soft photon production, and we review the current theoretical understanding of soft radiation and soft theorems. We also focus on low-mass dileptons as a tool for determining the electrical conductivity of the medium produced in high-energy nucleus–nucleus collisions. We discuss how both topics can be addressed with the planned ALICE 3 detector at the LHC.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1097 ","pages":"Pages 1-40"},"PeriodicalIF":23.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536312","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 : 2024-10-16DOI: 10.1016/j.physrep.2024.10.001
ATLAS Collaboration
This report presents a comprehensive collection of searches for new physics performed by the ATLAS Collaboration during the Run 2 period of data taking at the Large Hadron Collider, from 2015 to 2018, corresponding to about 140 fb−1 of proton–proton collision data. These searches cover a variety of beyond-the-standard model topics such as dark matter candidates, new vector bosons, hidden-sector particles, leptoquarks, or vector-like quarks, among others. Searches for supersymmetric particles or extended Higgs sectors are explicitly excluded as these are the subject of separate reports by the Collaboration. For each topic, the most relevant searches are described, focusing on their importance and sensitivity and, when appropriate, highlighting the experimental techniques employed. In addition to the description of each analysis, complementary searches are compared, and the overall sensitivity of the ATLAS experiment to each type of new physics is discussed. Summary plots and statistical combinations of multiple searches are included whenever possible.
{"title":"Exploration at the high-energy frontier: ATLAS Run 2 searches investigating the exotic jungle beyond the Standard Model","authors":"ATLAS Collaboration","doi":"10.1016/j.physrep.2024.10.001","DOIUrl":"10.1016/j.physrep.2024.10.001","url":null,"abstract":"<div><div>This report presents a comprehensive collection of searches for new physics performed by the ATLAS Collaboration during the Run 2 period of data taking at the Large Hadron Collider, from 2015 to 2018, corresponding to about 140 fb<sup>−1</sup> of <span><math><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mspace></mspace><mi>TeV</mi></mrow></math></span> proton–proton collision data. These searches cover a variety of beyond-the-standard model topics such as dark matter candidates, new vector bosons, hidden-sector particles, leptoquarks, or vector-like quarks, among others. Searches for supersymmetric particles or extended Higgs sectors are explicitly excluded as these are the subject of separate reports by the Collaboration. For each topic, the most relevant searches are described, focusing on their importance and sensitivity and, when appropriate, highlighting the experimental techniques employed. In addition to the description of each analysis, complementary searches are compared, and the overall sensitivity of the ATLAS experiment to each type of new physics is discussed. Summary plots and statistical combinations of multiple searches are included whenever possible.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1116 ","pages":"Pages 301-385"},"PeriodicalIF":23.9,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760863","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 : 2024-10-09DOI: 10.1016/j.physrep.2024.09.002
This report reviews the published results of searches for possible additional scalar particles and exotic decays of the Higgs boson performed by the ATLAS Collaboration using up to 140 fb−1 of 13 TeV proton–proton collision data collected during Run 2 of the Large Hadron Collider. Key results are examined, and observed excesses, while never statistically compelling, are noted. Constraints are placed on parameters of several models which extend the Standard Model, for example by adding one or more singlet or doublet fields, or offering exotic Higgs boson decay channels. Summaries of new searches as well as extensions of previous searches are discussed. These new results have a wider reach or attain stronger exclusion limits. New experimental techniques that were developed for these searches are highlighted. Search channels which have not yet been examined are also listed, as these provide insight into possible future areas of exploration.
{"title":"ATLAS searches for additional scalars and exotic Higgs boson decays with the LHC Run 2 dataset","authors":"","doi":"10.1016/j.physrep.2024.09.002","DOIUrl":"10.1016/j.physrep.2024.09.002","url":null,"abstract":"<div><div>This report reviews the published results of searches for possible additional scalar particles and exotic decays of the Higgs boson performed by the ATLAS Collaboration using up to 140 fb<sup>−1</sup> of 13 TeV proton–proton collision data collected during Run 2 of the Large Hadron Collider. Key results are examined, and observed excesses, while never statistically compelling, are noted. Constraints are placed on parameters of several models which extend the Standard Model, for example by adding one or more singlet or doublet fields, or offering exotic Higgs boson decay channels. Summaries of new searches as well as extensions of previous searches are discussed. These new results have a wider reach or attain stronger exclusion limits. New experimental techniques that were developed for these searches are highlighted. Search channels which have not yet been examined are also listed, as these provide insight into possible future areas of exploration.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1116 ","pages":"Pages 184-260"},"PeriodicalIF":23.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760866","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 : 2024-09-28DOI: 10.1016/j.physrep.2024.09.010
ATLAS Collaboration
The search for supersymmetry with the ATLAS experiment at the CERN Large Hadron Collider intensified after the discovery of the Higgs boson in 2012. The search programme expanded in both breadth and depth, profiting from the increased integrated luminosity and higher centre-of-mass energy for the collision data collected between 2015 and 2018, and gaining new sensitivity to unexplored areas of supersymmetry parameter space through the use of novel experimental signatures and innovative analysis techniques. This report summarises the supersymmetry searches at ATLAS using up to 140 fb−1 of collisions at , including the limits set on the production of gluinos, squarks, and electroweakinos for scenarios with or without R-parity conservation, and including models where some of the supersymmetric particles are long-lived.
{"title":"The quest to discover supersymmetry at the ATLAS experiment","authors":"ATLAS Collaboration","doi":"10.1016/j.physrep.2024.09.010","DOIUrl":"10.1016/j.physrep.2024.09.010","url":null,"abstract":"<div><div>The search for supersymmetry with the ATLAS experiment at the CERN Large Hadron Collider intensified after the discovery of the Higgs boson in 2012. The search programme expanded in both breadth and depth, profiting from the increased integrated luminosity and higher centre-of-mass energy for the collision data collected between 2015 and 2018, and gaining new sensitivity to unexplored areas of supersymmetry parameter space through the use of novel experimental signatures and innovative analysis techniques. This report summarises the supersymmetry searches at ATLAS using up to 140 fb<sup>−1</sup> of <span><math><mrow><mi>p</mi><mi>p</mi></mrow></math></span> collisions at <span><math><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mspace></mspace><mi>TeV</mi></mrow></math></span>, including the limits set on the production of gluinos, squarks, and electroweakinos for scenarios with or without R-parity conservation, and including models where some of the supersymmetric particles are long-lived.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1116 ","pages":"Pages 261-300"},"PeriodicalIF":23.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760864","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 : 2024-09-27DOI: 10.1016/j.physrep.2024.09.009
Paweł Cieśliński , Satoya Imai , Jan Dziewior , Otfried Gühne , Lukas Knips , Wiesław Laskowski , Jasmin Meinecke , Tomasz Paterek , Tamás Vértesi
Measurements with randomly chosen settings determine many important properties of quantum states without the need for a shared reference frame or calibration. They naturally emerge in the context of quantum communication and quantum computing when dealing with noisy environments, and allow the estimation of properties of complex quantum systems in an easy and efficient manner. In this review, we present the advancements made in utilising randomised measurements in various scenarios of quantum information science. We describe how to detect and characterise different forms of entanglement, including genuine multipartite entanglement and bound entanglement. Bell inequalities are discussed to be typically violated even with randomised measurements, especially for a growing number of particles and settings. Furthermore, we also present an overview on the estimation of non-linear functions of quantum states and shadow tomography from randomised measurements. Throughout the review, we complement the description of theoretical ideas by explaining key experiments.
{"title":"Analysing quantum systems with randomised measurements","authors":"Paweł Cieśliński , Satoya Imai , Jan Dziewior , Otfried Gühne , Lukas Knips , Wiesław Laskowski , Jasmin Meinecke , Tomasz Paterek , Tamás Vértesi","doi":"10.1016/j.physrep.2024.09.009","DOIUrl":"10.1016/j.physrep.2024.09.009","url":null,"abstract":"<div><div>Measurements with randomly chosen settings determine many important properties of quantum states without the need for a shared reference frame or calibration. They naturally emerge in the context of quantum communication and quantum computing when dealing with noisy environments, and allow the estimation of properties of complex quantum systems in an easy and efficient manner. In this review, we present the advancements made in utilising randomised measurements in various scenarios of quantum information science. We describe how to detect and characterise different forms of entanglement, including genuine multipartite entanglement and bound entanglement. Bell inequalities are discussed to be typically violated even with randomised measurements, especially for a growing number of particles and settings. Furthermore, we also present an overview on the estimation of non-linear functions of quantum states and shadow tomography from randomised measurements. Throughout the review, we complement the description of theoretical ideas by explaining key experiments.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1095 ","pages":"Pages 1-48"},"PeriodicalIF":23.9,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357839","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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