Pub Date : 2026-01-16DOI: 10.1088/1361-6633/ae3982
Murod Mirzhalilov,Nandini Trivedi,Mohit Randeria
We theoretically analyze the topological insulator (TI) surface state mediated interactions between local moments in a proximate 2D ferromagnetic insulator (FMI) motivated by recent experiments that show a significant increase in the Curie temperature Tc of FMI-TI heterostructures. Such interactions have been investigated earlier with a focus on dilute magnetic dopants in TIs. Our problem involves a dense set of moments for which we find that the short range Bloembergen-Rowland interaction, arising from virtual particle-hole transitions between the valence and conduction bands, dominates over the oscillatory Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. We show that the Tc enhancement is proportional to the Van Vleck susceptibility and that the spin-momentum locking of surface states leads to out-of-plane ferromagnetic order in the FMI. We investigate how the hybridization between top and bottom surfaces in a thin TI film impacts Tc enhancement, and show how our results can help understand recent experiments on atomically thin Cr2Te3-(Bi,Sb)2Te3. Our results advance the understanding of magnetic interactions relevant for TI-based spintronic and magnonic devices.
{"title":"Enhancement of Curie Temperature in Ferromagnetic Insulator-Topological Insulator Heterostructures.","authors":"Murod Mirzhalilov,Nandini Trivedi,Mohit Randeria","doi":"10.1088/1361-6633/ae3982","DOIUrl":"https://doi.org/10.1088/1361-6633/ae3982","url":null,"abstract":"We theoretically analyze the topological insulator (TI) surface state mediated interactions between local moments in a proximate 2D ferromagnetic insulator (FMI) motivated by recent experiments that show a significant increase in the Curie temperature Tc of FMI-TI heterostructures. Such interactions have been investigated earlier with a focus on dilute magnetic dopants in TIs. Our problem involves a dense set of moments for which we find that the short range Bloembergen-Rowland interaction, arising from virtual particle-hole transitions between the valence and conduction bands, dominates over the oscillatory Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. We show that the Tc enhancement is proportional to the Van Vleck susceptibility and that the spin-momentum locking of surface states leads to out-of-plane ferromagnetic order in the FMI. We investigate how the hybridization between top and bottom surfaces in a thin TI film impacts Tc enhancement, and show how our results can help understand recent experiments on atomically thin Cr2Te3-(Bi,Sb)2Te3. Our results advance the understanding of magnetic interactions relevant for TI-based spintronic and magnonic devices.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"24 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145986350","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 : 2026-01-16DOI: 10.1088/1361-6633/ae3983
Xiaoliang Xiao,Xingyu Yue,Jinyang Ni,Jin-Zhu Zhao,Ruiqiang Wang,Xin Wang,Guoqing Chang,Yuanjun Jin
Manipulating the nonlinear Hall effect (NLHE) through non-volatile approach is of great significance for device applications, yet effective gating control remains elusive. In this Letter, using first-principles calculations and symmetry analysis, we propose a universal design principle for gate-field control of the NLHE in bilayer systems. Using bilayer SnSe and SnTe, the well-known ferroelectric and thermoelectric materials, as examples, it reveals that the inherent hidden polarization can activate a layer-locked hidden Berry curvature dipole (BCD) under an applied gate field, thereby inducing a giant nonlinear Hall current. The hidden polarization locked to BCD in a gate field, experiences a pseudospin Zeeman field as a spin in magnetic field. Therefore, reversing the direction of the gate-field can switch the preferred pseudospin orientation, enabling the switchable second-order NLHE. This mechanism does not require intrinsic magnetism and provides a binary ON/OFF switching control method, greatly expanding the application potential of layered systems in nonlinear Hall transport. Our findings not only demonstrate the universal design principle of the switchable second-order NLHE but also can be extended to other gate-field-controllable nonlinear transport and nonlinear optics.
{"title":"A universal design principle for switchable control of the second-order nonlinear Hall effect.","authors":"Xiaoliang Xiao,Xingyu Yue,Jinyang Ni,Jin-Zhu Zhao,Ruiqiang Wang,Xin Wang,Guoqing Chang,Yuanjun Jin","doi":"10.1088/1361-6633/ae3983","DOIUrl":"https://doi.org/10.1088/1361-6633/ae3983","url":null,"abstract":"Manipulating the nonlinear Hall effect (NLHE) through non-volatile approach is of great significance for device applications, yet effective gating control remains elusive. In this Letter, using first-principles calculations and symmetry analysis, we propose a universal design principle for gate-field control of the NLHE in bilayer systems. Using bilayer SnSe and SnTe, the well-known ferroelectric and thermoelectric materials, as examples, it reveals that the inherent hidden polarization can activate a layer-locked hidden Berry curvature dipole (BCD) under an applied gate field, thereby inducing a giant nonlinear Hall current. The hidden polarization locked to BCD in a gate field, experiences a pseudospin Zeeman field as a spin in magnetic field. Therefore, reversing the direction of the gate-field can switch the preferred pseudospin orientation, enabling the switchable second-order NLHE. This mechanism does not require intrinsic magnetism and provides a binary ON/OFF switching control method, greatly expanding the application potential of layered systems in nonlinear Hall transport. Our findings not only demonstrate the universal design principle of the switchable second-order NLHE but also can be extended to other gate-field-controllable nonlinear transport and nonlinear optics.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"83 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145986351","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}
Physical reservoir computing (RC) systems have emerged as a prominent research frontier due to their exceptional efficiency in temporal information processing. However, existing implementations, predominantly utilizing resistive devices, face challenges pertaining to power efficiency and dynamic richness. Here, we propose a ferroelectric capacitor-linear capacitor (FC-LC) series device for RC implementation. By leveraging nonlinear polarization switching and back-switching, the FC-LC series device realizes two essential reservoir properties: nonlinearity and fading memory. In addition, the device exhibits an ultralow power consumption, which, along with its direct voltage readout capability, marks a significant advance over resistive reservoir devices. Moreover, the device features bidirectional operation and widely tunable time constants, thereby enhancing reservoir space dimensionality and state richness. Building upon these FC-LC series devices, a ferroelectric capacitive RC system is developed, which demonstrates superior performance in various benchmark tasks. By exploiting the bidirectional operation of the device, the RC system not only delivers enhanced performance in waveform classification but also enables highaccuracy multimodal digit recognition. Through strategically hybridizing the FC-LC series devices with varying time constants, the RC system achieves remarkable performance in Mackey-Glass time-series prediction. Our study paves the way for power-efficient, dynamicrich RC systems capable of handling diverse temporal tasks.
{"title":"Ultralow-power reservoir computing based on bidirectionally operable ferroelectric capacitors with tunable time constants.","authors":"Linyuan Mo,Zhen Fan,Jiali Ou,Zhiwei Chen,Haipeng Lin,Wenjie Hu,Wenjie Li,Meixia Li,Boyuan Cui,Hua Fan,Ruiqiang Tao,Guo Tian,Minghui Qin,Xubing Lu,Guofu Zhou,Xingsen Gao,Junming Liu","doi":"10.1088/1361-6633/ae3984","DOIUrl":"https://doi.org/10.1088/1361-6633/ae3984","url":null,"abstract":"Physical reservoir computing (RC) systems have emerged as a prominent research frontier due to their exceptional efficiency in temporal information processing. However, existing implementations, predominantly utilizing resistive devices, face challenges pertaining to power efficiency and dynamic richness. Here, we propose a ferroelectric capacitor-linear capacitor (FC-LC) series device for RC implementation. By leveraging nonlinear polarization switching and back-switching, the FC-LC series device realizes two essential reservoir properties: nonlinearity and fading memory. In addition, the device exhibits an ultralow power consumption, which, along with its direct voltage readout capability, marks a significant advance over resistive reservoir devices. Moreover, the device features bidirectional operation and widely tunable time constants, thereby enhancing reservoir space dimensionality and state richness. Building upon these FC-LC series devices, a ferroelectric capacitive RC system is developed, which demonstrates superior performance in various benchmark tasks. By exploiting the bidirectional operation of the device, the RC system not only delivers enhanced performance in waveform classification but also enables highaccuracy multimodal digit recognition. Through strategically hybridizing the FC-LC series devices with varying time constants, the RC system achieves remarkable performance in Mackey-Glass time-series prediction. Our study paves the way for power-efficient, dynamicrich RC systems capable of handling diverse temporal tasks.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"268 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145986347","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}
Negative thermal expansion (NTE) refers to volume contraction upon heating, but the intrinsic complexity of its physical mechanisms presents a fundamental challenge. α-Cu2V2O7 exhibits significant anisotropic NTE over a wider temperature range; however, its NTE mechanism has not been clearly elucidated. Herein, we systematically investigate the NTE mechanism of α-Cu2V2O7 using neutron powder diffraction, synchrotron radiation X-ray diffraction, and temperature- and pressure-dependent Raman spectra, and density functional theory calculations across 5 - 800 K. The structure exhibits a second-order Jahn-Teller (SOJT) effect, which is the primary cause of off-centering within the quasi-CuO6 octahedra. As temperature increases, the SOJT effect weakens, reducing the distortion of the driving force for off-centering; this causes the Cu atoms to shift in opposite directions, increasing symmetry. The anti-off-centering displacement of the Cu atoms toward the O4(long) atoms in the quasi-CuO6 octahedra compresses the Cu···Cu zigzag chains and reduces the spacing between orthogonal chains, resulting in the NTE behavior of α-Cu2V2O7. This study reveals a novel mechanism whereby the SOJT effect governs the displacement and symmetry of Cu atoms, providing crucial insight into the origin of NTE behavior in α-Cu2V2O7. These findings could help the community advance the understanding of NTE in anisotropic materials.
{"title":"Jahn-Teller distortions induced strong negative thermal expansion in α-Cu2V2O7.","authors":"Xiangkai Hao,Shibo Zhao,Qilong Gao,Yongqiang Qiao,Andrea Sanson,K Matan,G Gitgeatpong,Qiang Sun,Juan Guo,Feng Jin,Lunhua He,Shogo Kawaguchi,Erjun Liang,Jun Chen","doi":"10.1088/1361-6633/ae3853","DOIUrl":"https://doi.org/10.1088/1361-6633/ae3853","url":null,"abstract":"Negative thermal expansion (NTE) refers to volume contraction upon heating, but the intrinsic complexity of its physical mechanisms presents a fundamental challenge. α-Cu2V2O7 exhibits significant anisotropic NTE over a wider temperature range; however, its NTE mechanism has not been clearly elucidated. Herein, we systematically investigate the NTE mechanism of α-Cu2V2O7 using neutron powder diffraction, synchrotron radiation X-ray diffraction, and temperature- and pressure-dependent Raman spectra, and density functional theory calculations across 5 - 800 K. The structure exhibits a second-order Jahn-Teller (SOJT) effect, which is the primary cause of off-centering within the quasi-CuO6 octahedra. As temperature increases, the SOJT effect weakens, reducing the distortion of the driving force for off-centering; this causes the Cu atoms to shift in opposite directions, increasing symmetry. The anti-off-centering displacement of the Cu atoms toward the O4(long) atoms in the quasi-CuO6 octahedra compresses the Cu···Cu zigzag chains and reduces the spacing between orthogonal chains, resulting in the NTE behavior of α-Cu2V2O7. This study reveals a novel mechanism whereby the SOJT effect governs the displacement and symmetry of Cu atoms, providing crucial insight into the origin of NTE behavior in α-Cu2V2O7. These findings could help the community advance the understanding of NTE in anisotropic materials.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"41 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145971886","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 : 2025-12-15DOI: 10.1088/1361-6633/ae2ca2
Manlio De Domenico
The possibility that evolutionary forces -- together with a few fundamental factors such as thermodynamic constraints, specific computational features enabling information processing, and ecological processes -- might constrain the logic of living systems is tantalizing. However, it is often overlooked that any practical implementation of such a logic requires complementary circuitry that, in biological systems, happens through complex networks of genetic regulation, metabolic reactions, cellular signalling, communication, social and eusocial non-trivial organization. Here, we review and discuss how circuitries are not merely passive structures, but active agents of change that, by means of hierarchical and modular organization, are able to enhance and catalyze the evolution of evolvability. By analyzing the role of non-trivial topologies in major evolutionary transitions under the lens of statistical physics and nonlinear dynamics, we show that biological innovations are strictly related to circuitry and its deviation from trivial structures and (thermo)dynamic equilibria.
We argue that sparse heterogeneous networks such as hierarchical modular, which are ubiquitously observed in nature, are favored in terms of the trade-off between energetic costs for redundancy, error-correction and mantainance. We identify three main features -- namely, interconnectivity, plasticity and interdependency -- pointing towards a unifying framework for modeling the phenomenology, discussing them in terms of dynamical systems theory, non-equilibrium thermodynamics and evolutionary dynamics. Within this unified picture, we also show that "slow" evolutionary dynamics is an emergent phenomenon governed by the replicator-mutator equation as the direct consequence of a constrained variational nonequilibrium process. Overall, this work highlights how dynamical systems theory and nonequilibrium thermodynamics provide powerful analytical techniques to study biological complexity.
{"title":"Decoding the architecture of living systems.","authors":"Manlio De Domenico","doi":"10.1088/1361-6633/ae2ca2","DOIUrl":"https://doi.org/10.1088/1361-6633/ae2ca2","url":null,"abstract":"The possibility that evolutionary forces -- together with a few fundamental factors such as thermodynamic constraints, specific computational features enabling information processing, and ecological processes -- might constrain the logic of living systems is tantalizing. However, it is often overlooked that any practical implementation of such a logic requires complementary circuitry that, in biological systems, happens through complex networks of genetic regulation, metabolic reactions, cellular signalling, communication, social and eusocial non-trivial organization. Here, we review and discuss how circuitries are not merely passive structures, but active agents of change that, by means of hierarchical and modular organization, are able to enhance and catalyze the evolution of evolvability. By analyzing the role of non-trivial topologies in major evolutionary transitions under the lens of statistical physics and nonlinear dynamics, we show that biological innovations are strictly related to circuitry and its deviation from trivial structures and (thermo)dynamic equilibria. 

We argue that sparse heterogeneous networks such as hierarchical modular, which are ubiquitously observed in nature, are favored in terms of the trade-off between energetic costs for redundancy, error-correction and mantainance. We identify three main features -- namely, interconnectivity, plasticity and interdependency -- pointing towards a unifying framework for modeling the phenomenology, discussing them in terms of dynamical systems theory, non-equilibrium thermodynamics and evolutionary dynamics. Within this unified picture, we also show that \"slow\" evolutionary dynamics is an emergent phenomenon governed by the replicator-mutator equation as the direct consequence of a constrained variational nonequilibrium process. Overall, this work highlights how dynamical systems theory and nonequilibrium thermodynamics provide powerful analytical techniques to study biological complexity.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"43 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760086","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}
Studies of ground-state topology in quantum materials have revealed the discovery of topological phases with novel Hall responses. Recently, the orbital Hall effect has drawn growing attention; however, the hidden origin behind large orbital Hall conductivity in insulators remains elusive. Here, we introduce the concept of orbital Chern insulators (OCIs), a previously unexplored topological phase in which orbital angular momentum drives nontrivial topology and hosts the orbital Hall effect in insulating systems. We establish a comprehensive orbital-topology-based framework for systematically characterizing OCIs, and identify monolayer blue phosphorene, a material previously regarded as a trivial insulator, hosting the first pure OCI with robust topological boundary states. We demonstrate that OCI is entirely orbital driven, fully disentangled from the spin and valley degrees of freedom, resulting in an orbital Hall effect that can be experimentally distinguished from the spin and valley Hall effects in insulating materials. Our work suggests a new avenue for exploring orbital topology in materials and advancing orbitronics-based technologies.
{"title":"Orbital topology induced orbital Hall effect in two-dimensional insulators.","authors":"Yueh-Ting Yao,Chia-Hung Chu,Arun Bansil,Hsin Lin,Tay-Rong Chang","doi":"10.1088/1361-6633/ae2a68","DOIUrl":"https://doi.org/10.1088/1361-6633/ae2a68","url":null,"abstract":"Studies of ground-state topology in quantum materials have revealed the discovery of topological phases with novel Hall responses. Recently, the orbital Hall effect has drawn growing attention; however, the hidden origin behind large orbital Hall conductivity in insulators remains elusive. Here, we introduce the concept of orbital Chern insulators (OCIs), a previously unexplored topological phase in which orbital angular momentum drives nontrivial topology and hosts the orbital Hall effect in insulating systems. We establish a comprehensive orbital-topology-based framework for systematically characterizing OCIs, and identify monolayer blue phosphorene, a material previously regarded as a trivial insulator, hosting the first pure OCI with robust topological boundary states. We demonstrate that OCI is entirely orbital driven, fully disentangled from the spin and valley degrees of freedom, resulting in an orbital Hall effect that can be experimentally distinguished from the spin and valley Hall effects in insulating materials. Our work suggests a new avenue for exploring orbital topology in materials and advancing orbitronics-based technologies.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"35 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145710755","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 : 2025-12-05DOI: 10.1088/1361-6633/ae2888
Felipe Reyes-Osorio,Federico Garcia-Gaitan,David J Strachan,Petr Plechac,Stephen Richard Clark,Branislav K Nikolic
We develop a unified framework for open quantum systems composed of many mutually interacting quantum spins, or any isomorphic systems like qubits and qudits, surrounded by one or more independent bosonic baths. Our framework, based on Schwinger-Keldysh field theory (SKFT), can handle arbitrary spin value S, dimensionality of space, and geometry while being applicable to a large parameter space for system and bath or their coupling. It can probe regimes in which non-Markovian dynamics and nonperturbative effects pose formidable challenges for other state-of-the-art theoretical methods. This is achieved by working with the two-particle irreducible (2PI) effective action, which resums classes of Feynman diagrams of SKFT to an infinite order. Furthermore, such diagrams are generated via an expansion in 1/N, where N is the number of Schwinger bosons we employ to map spin operators onto canonically commuting ones, rather than via conventional expansion in system-bath coupling constant. We carefully benchmark our SKFT+2PI-computed results vs. numerically (quasi)exact ones from tensor network calculations applied to the archetypical spin-boson model where both methodologies are applicable. Additionally, we demonstrate the capability of SKFT+2PI to handle a much more complex spin-chain-boson model with multiple baths interacting with each spin where no benchmark from other methods is available at present. The favorable numerical cost of solving integro-differential equations produced by the SKFT+2PI framework with an increasing number of spins and time steps makes it a promising route for simulating driven-dissipative systems in quantum computing, quantum magnonics, and quantum spintronics.
.
{"title":"Schwinger-Keldysh non-perturbative field theory of open quantum systems beyond the Markovian regime: Application to spin-boson and spin-chain-boson models.","authors":"Felipe Reyes-Osorio,Federico Garcia-Gaitan,David J Strachan,Petr Plechac,Stephen Richard Clark,Branislav K Nikolic","doi":"10.1088/1361-6633/ae2888","DOIUrl":"https://doi.org/10.1088/1361-6633/ae2888","url":null,"abstract":"We develop a unified framework for open quantum systems composed of many mutually interacting quantum spins, or any isomorphic systems like qubits and qudits, surrounded by one or more independent bosonic baths. Our framework, based on Schwinger-Keldysh field theory (SKFT), can handle arbitrary spin value S, dimensionality of space, and geometry while being applicable to a large parameter space for system and bath or their coupling. It can probe regimes in which non-Markovian dynamics and nonperturbative effects pose formidable challenges for other state-of-the-art theoretical methods. This is achieved by working with the two-particle irreducible (2PI) effective action, which resums classes of Feynman diagrams of SKFT to an infinite order. Furthermore, such diagrams are generated via an expansion in 1/N, where N is the number of Schwinger bosons we employ to map spin operators onto canonically commuting ones, rather than via conventional expansion in system-bath coupling constant. We carefully benchmark our SKFT+2PI-computed results vs. numerically (quasi)exact ones from tensor network calculations applied to the archetypical spin-boson model where both methodologies are applicable. Additionally, we demonstrate the capability of SKFT+2PI to handle a much more complex spin-chain-boson model with multiple baths interacting with each spin where no benchmark from other methods is available at present. The favorable numerical cost of solving integro-differential equations produced by the SKFT+2PI framework with an increasing number of spins and time steps makes it a promising route for simulating driven-dissipative systems in quantum computing, quantum magnonics, and quantum spintronics.
.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"1 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145680626","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 : 2025-11-20DOI: 10.1088/1361-6633/ae2206
Mickael Chekroun,Niccolò Zagli,Valerio Lucarini
We present a generalization of linear response theory for mixed jump-diffusion models-which combine both Gaussian and Lévy noise forcings that interact with the nonlinear dynamics-by deriving a comprehensive response formulas that accounts for perturbations to both the drift term and the jumps law. This class of models is particularly relevant for parameterizing the effects of unresolved scales in complex systems. Our formulas are thus particularly relevant to quantify uncertainties in either what needs to be parameterized (e.g. the jumps law), or to measure dynamical changes due to perturbations of the drift term (e.g. parameter variations). By generalizing the concepts of Kolmogorov operators and Green's functions, we obtain new forms of fluctuation-dissipation relations. The resulting response is decomposed into contributions from the eigenmodes of the Kolmogorov operator, providing a fresh look into the intimate relationship between a system's natural and forced variability. We demonstrate the theory's predictive power with two distinct climate-centric applications. First, we apply our framework to a paradigmatic El Niño-Southern Oscillation (ENSO) model subject to state-dependent jumps and additive white noise, showing how the theory accurately predicts the system's response to perturbations and how Kolmogorov modes can be used to diagnose its complex time variability. In a second, more challenging application, we use our linear response theory to perform accurate climate change projections in the Ghil-Sellers (GS) energy balance climate model, which is a spatially-extended model forced here by a spatio-temporal αstable process. This work provides a comprehensive approach to climate modeling and prediction that enriches Hasselmann's program, with implications for understanding climate sensitivity, detection and attribution of climate change, and assessing the risk of climate tipping points. Our results may find applications beyond the realm of climate, and seem of relevance for epidemiology, biology, finance, and quantitative social sciences, among others.
{"title":"Kolmogorov modes and linear response of jump-diffusion models.","authors":"Mickael Chekroun,Niccolò Zagli,Valerio Lucarini","doi":"10.1088/1361-6633/ae2206","DOIUrl":"https://doi.org/10.1088/1361-6633/ae2206","url":null,"abstract":"We present a generalization of linear response theory for mixed jump-diffusion models-which combine both Gaussian and Lévy noise forcings that interact with the nonlinear dynamics-by deriving a comprehensive response formulas that accounts for perturbations to both the drift term and the jumps law. This class of models is particularly relevant for parameterizing the effects of unresolved scales in complex systems. Our formulas are thus particularly relevant to quantify uncertainties in either what needs to be parameterized (e.g. the jumps law), or to measure dynamical changes due to perturbations of the drift term (e.g. parameter variations). By generalizing the concepts of Kolmogorov operators and Green's functions, we obtain new forms of fluctuation-dissipation relations. The resulting response is decomposed into contributions from the eigenmodes of the Kolmogorov operator, providing a fresh look into the intimate relationship between a system's natural and forced variability. We demonstrate the theory's predictive power with two distinct climate-centric applications. First, we apply our framework to a paradigmatic El Niño-Southern Oscillation (ENSO) model subject to state-dependent jumps and additive white noise, showing how the theory accurately predicts the system's response to perturbations and how Kolmogorov modes can be used to diagnose its complex time variability. In a second, more challenging application, we use our linear response theory to perform accurate climate change projections in the Ghil-Sellers (GS) energy balance climate model, which is a spatially-extended model forced here by a spatio-temporal αstable process. This work provides a comprehensive approach to climate modeling and prediction that enriches Hasselmann's program, with implications for understanding climate sensitivity, detection and attribution of climate change, and assessing the risk of climate tipping points. Our results may find applications beyond the realm of climate, and seem of relevance for epidemiology, biology, finance, and quantitative social sciences, among others.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"80 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145559008","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 : 2025-10-31DOI: 10.1088/1361-6633/ae1a15
Jun-Ying Jiang,Liang Gao,Hai-Bin Yu
Glass materials, as quintessential non-equilibrium systems, exhibit properties such as energy dissipation that are highly sensitive to their preparation histories. A key challenge has been identifying a unified order parameter to rationalize these properties. Here, we
demonstrate that a configurational distance metric can effectively collapse energy dissipation data across diverse preparation histories and testing protocols, including varying cooling rates, aging processes, probing times, and the amplitudes of mechanical excitation, as long as the temperature remains above the kinetic ideal glass transition temperature (where the extrapolated structural relaxation time diverges). Our results provide a unified description of the non-equilibrium dissipation and suggest that the putative concept of the kinetic ideal glass transition is imprinted in material characteristics.
{"title":"Order parameter for non-equilibrium dissipation and ideal glass.","authors":"Jun-Ying Jiang,Liang Gao,Hai-Bin Yu","doi":"10.1088/1361-6633/ae1a15","DOIUrl":"https://doi.org/10.1088/1361-6633/ae1a15","url":null,"abstract":"Glass materials, as quintessential non-equilibrium systems, exhibit properties such as energy dissipation that are highly sensitive to their preparation histories. A key challenge has been identifying a unified order parameter to rationalize these properties. Here, we
demonstrate that a configurational distance metric can effectively collapse energy dissipation data across diverse preparation histories and testing protocols, including varying cooling rates, aging processes, probing times, and the amplitudes of mechanical excitation, as long as the temperature remains above the kinetic ideal glass transition temperature (where the extrapolated structural relaxation time diverges). Our results provide a unified description of the non-equilibrium dissipation and suggest that the putative concept of the kinetic ideal glass transition is imprinted in material characteristics.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"1 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145411601","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}
Spin and orbital angular momenta (AM) are of fundamental importance in physics. Acoustic waves, as typical longitudinal waves, have been well studied in terms of orbital AM but not for spin AM, as they are often perceived as spin-0 waves. Although spin AM density has been found in acoustics, the total spin AM is, however, often vanishing. At material boundaries, finite total spin AM and spin-orbit interaction can arise for evanescent waves but only for transverse spin AM not for longitudinal spin AM. Here, from a self-consistent theoretical frame, we establish the spin, orbital, and total AM of acoustic vortex beams, and discover that a non-zero integral longitudinal spin AM is carried by the propagating acoustic field. With the longitudinal acoustic spin, we unveil a new mechanism of spin-orbit interaction emerging when a vortex beam is compressed or expanded. Moreover, we reveal the connection and distinction between the acoustic canonical-Minkowski and kinetic-Abraham AM, and prove that only the former is conserved under the corresponding symmetry. Based on these findings, we propose new strategies for manipulating acoustic spin and orbital AM. Our discovery elucidates new fundamental aspects of spin and orbital AM as well as their interplay in acoustics, which can be extended to other classical waves and may open up new ways for AM-based applications in these systems.
自旋角动量和轨道角动量在物理学中具有重要的基础意义。声波作为典型的纵波，已经在轨道调幅方面进行了很好的研究，但对于自旋调幅却没有，因为它们通常被认为是自旋0波。虽然在声学中发现了自旋调幅的密度，但总的自旋调幅常常消失。在材料边界处，有限总自旋AM和自旋轨道相互作用可以产生倏逝波，但只有横向自旋AM而不是纵向自旋AM。本文从一个自洽的理论框架出发，建立了声涡旋波束的自旋、轨道和总调幅，发现了一个非零积分纵向自旋调幅是由传播的声场携带的。利用纵向声自旋，我们揭示了涡旋束被压缩或膨胀时出现的自旋-轨道相互作用的新机制。此外，我们揭示了声学经典- minkowski和动力学- abraham AM之间的联系和区别，并证明了在相应的对称下只有前者是守恒的。基于这些发现，我们提出了操纵声自旋和轨道调幅的新策略。我们的发现阐明了自旋和轨道调幅的新基本方面以及它们在声学中的相互作用，这可以扩展到其他经典波，并可能为这些系统中基于调幅的应用开辟新的途径。
{"title":"Longitudinal acoustic spin and global spin-orbit interaction in vortex beams.","authors":"Wei Wang,Yang Tan,Jingjing Liu,JianHua Jiang,Bin Liang,Jianchun Cheng","doi":"10.1088/1361-6633/ae15bc","DOIUrl":"https://doi.org/10.1088/1361-6633/ae15bc","url":null,"abstract":"Spin and orbital angular momenta (AM) are of fundamental importance in physics. Acoustic waves, as typical longitudinal waves, have been well studied in terms of orbital AM but not for spin AM, as they are often perceived as spin-0 waves. Although spin AM density has been found in acoustics, the total spin AM is, however, often vanishing. At material boundaries, finite total spin AM and spin-orbit interaction can arise for evanescent waves but only for transverse spin AM not for longitudinal spin AM. Here, from a self-consistent theoretical frame, we establish the spin, orbital, and total AM of acoustic vortex beams, and discover that a non-zero integral longitudinal spin AM is carried by the propagating acoustic field. With the longitudinal acoustic spin, we unveil a new mechanism of spin-orbit interaction emerging when a vortex beam is compressed or expanded. Moreover, we reveal the connection and distinction between the acoustic canonical-Minkowski and kinetic-Abraham AM, and prove that only the former is conserved under the corresponding symmetry. Based on these findings, we propose new strategies for manipulating acoustic spin and orbital AM. Our discovery elucidates new fundamental aspects of spin and orbital AM as well as their interplay in acoustics, which can be extended to other classical waves and may open up new ways for AM-based applications in these systems.","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"2 1","pages":""},"PeriodicalIF":18.1,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145338521","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}
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