Physical Review X最新文献

{"title":"High Capacity and Dynamic Accessibility in Associative Memory Networks with Context-Dependent Neuronal and Synaptic Gating","authors":"William F. Podlaski, Everton J. Agnes, Tim P. Vogels","doi":"10.1103/physrevx.15.011057","DOIUrl":"https://doi.org/10.1103/physrevx.15.011057","url":null,"abstract":"Biological memory is known to be flexible—memory formation and recall depend on factors such as the behavioral context of the organism. However, this property is often ignored in associative memory models, leaving it unclear how memories can be organized and recalled when subject to contextual control. Because of the lack of a rigorous analytical framework, it is also unknown how contextual control affects memory stability, storage capacity, and information content. Here, we bring the dynamic nature of memory to the fore by introducing a novel model of associative memory, which we refer to as the context-modular memory network. In our model, stored memory patterns are associated to one of several background network states, or contexts. Memories are accessible when their corresponding context is active, and are otherwise inaccessible. Context modulates the effective network connectivity by imposing a specific configuration of neuronal and synaptic gating—gated neurons (synapses) have their activity (weights) momentarily silenced, thereby reducing interference from memories belonging to other contexts. Memory patterns are randomly and independently chosen, while neuronal and synaptic gates may be selected randomly or optimized through a process of contextual synaptic refinement. Through analytic and numerical results, we show that context-modular memory networks can exhibit both improved memory capacity and differential control of memory stability with random gating (especially for neuronal gating). For contextual synaptic refinement, we devise a method in which synapses are gated off for a given context if they destabilize the memory patterns in that context, drastically improving memory capacity and enabling even more precise control over memory stability. Notably, synaptic refinement allows for patterns to be accessible in multiple contexts, stabilizing memory patterns even for weight matrices that alone do not contain any information about the memory patterns, such as Gaussian random matrices. Overall, our model integrates recent ideas about context-dependent memory organization with classic associative memory models and proposes a rigorous theory which can act as a framework for future work. Furthermore, our work carries important implications for the understanding of biological memory storage and recall in the brain, such as highlighting an intriguing trade-off between memory capacity and accessibility. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"18 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618705","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}

{"title":"Experimental Realization of Discrete Time Quasicrystals","authors":"Guanghui He, Bingtian Ye, Ruotian Gong, Changyu Yao, Zhongyuan Liu, Kater W. Murch, Norman Y. Yao, Chong Zu","doi":"10.1103/physrevx.15.011055","DOIUrl":"https://doi.org/10.1103/physrevx.15.011055","url":null,"abstract":"Floquet (periodically driven) systems can give rise to unique nonequilibrium phases of matter without equilibrium analogs. The most prominent example is the realization of discrete time crystals. An intriguing question emerges: What other novel phases can manifest when the constraint of time periodicity is relaxed? In this study, we explore quantum systems subjected to a quasiperiodic drive. Leveraging a strongly interacting spin ensemble in diamond, we identify the emergence of long-lived discrete time quasicrystals. Unlike conventional time crystals, time quasicrystals exhibit robust subharmonic responses at multiple incommensurate frequencies. Furthermore, we show that the multifrequency nature of the quasiperiodic drive allows for the formation of diverse patterns associated with different discrete time quasicrystalline phases. Our findings demonstrate the existence of nonequilibrium phases in quasi-Floquet settings, significantly broadening the catalog of novel phenomena in driven many-body quantum systems. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"56 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608173","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}

{"title":"Entanglement Witness for Indistinguishable Electrons Using Solid-State Spectroscopy","authors":"Tongtong Liu, Luogen Xu, Jiarui Liu, Yao Wang","doi":"10.1103/physrevx.15.011056","DOIUrl":"https://doi.org/10.1103/physrevx.15.011056","url":null,"abstract":"Characterizing entanglement in quantum materials is crucial for advancing next-generation quantum technologies. Despite recent strides in witnessing entanglement in magnetic materials with distinguishable spin modes, quantifying entanglement in systems formed by indistinguishable electrons remains a formidable challenge. To solve this problem, we introduce a method to extract various four-fermion correlations by analyzing the nonlinearity in resonant inelastic x-ray scattering spectra. These correlations constitute the primary components of the cumulant two-particle reduced density matrix. We further derive bounds for its eigenvalues and demonstrate the linear scaling with fermionic entanglement depth, providing a reliable witness for entanglement. Using the material-relevant strongly correlated models as examples, we show how this entanglement witness can efficiently quantify multipartite entanglement across different phase regions, highlighting its advantage over quantum Fisher information. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"33 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608401","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}

{"title":"Topological Hall Effect of Skyrmions from first Principles","authors":"Hsiao-Yi Chen, Takuya Nomoto, Max Hirschberger, Ryotaro Arita","doi":"10.1103/physrevx.15.011054","DOIUrl":"https://doi.org/10.1103/physrevx.15.011054","url":null,"abstract":"We formulate a first-principles approach for calculating the topological Hall effect (THE) in magnets with noncollinear nanoscale spin textures. We employ a modeling method to determine the effective magnetic field induced by the spin texture, thereby circumventing the computational challenges associated with superlattice calculations. Based on these results, we construct a Wannier tight-binding Hamiltonian to characterize the electronic states and calculate the Hall conductivity. Applying this approach to the skyrmion material Gd</a:mi></a:mrow>2</a:mn></a:msub>PdSi</a:mi></a:mrow>3</a:mn></a:msub></a:mrow></a:math> shows good agreement with experimental data. Our analysis in momentum space further reveals that the dominant contribution to the THE arises from the crossing points between the folded bands along high-symmetry lines in the Brillouin zone. This work advances numerical techniques for simulating a general magnetic system, exemplified by but not restricted to skyrmion lattice, and its result offering insights into the complex interplay between spin textures and electronic transport. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"45 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143598894","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}

{"title":"Damaging Intermolecular Relaxation Processes Initiated by Heavy-Ion Irradiation of Hydrated Biomolecules","authors":"Yue Gao, Anna D. Skitnevskaya, Enliang Wang, Hang Yuan, Xueguang Ren, Hong Lin, Zhenyu Yan, Shaofeng Zhang, Shaofei Gu, Bo Yang, Feng Fang, Shuncheng Yan, Dalong Guo, Xiaolong Zhu, Dongmei Zhao, Caojie Shao, Zhongkui Huang, Xiaorui Xue, Xintai Hao, Jiaqi Zhou, Tongmin Zhang, Jinyu Li, Xinliang Yan, Meng Wang, Lijun Mao, Dayu Yin, Meitang Tang, Youjin Yuan, Jiancheng Yang, Alexander B. Trofimov, Lorenz S. Cederbaum, Alexander I. Kuleff, Xinwen Ma, Shenyue Xu","doi":"10.1103/physrevx.15.011053","DOIUrl":"https://doi.org/10.1103/physrevx.15.011053","url":null,"abstract":"Intermolecular Coulombic decay (ICD) is considered a general phenomenon that plays a key role in many fundamental and applied fields related to biological environments. In many cases, however, the mechanisms and efficiency of ICD have yet to be uncovered. A prominent example is heavy-ion cancer therapy. Here, we report the first detection of a damaging intermolecular relaxation cascade initiated by heavy-ion bombardment of hydrated pyrimidine clusters. The process can significantly contribute to the high biological effectiveness of heavy-ion irradiation and thus might play an essential role in many radiotherapy techniques. Inner-valence ionization of the cluster initiates ICD and triggers proton transfer between water molecules, producing destructive low-energy electrons, HO</a:mi></a:mrow>•</a:mo></a:mrow></a:msup></a:mrow></a:math> radicals, and hydrated protons. Notably, the efficiency of ICD was found to increase dramatically with the number of water molecules, making ICD the dominant decay mechanism after inner-valence ionization. These findings indicate that the biological damage, caused by ICD in aqueous environments, is much more severe than was previously recognized. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"52 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599004","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}

{"title":"Electric-Field Switchable Chirality in Rhombohedral Graphene Chern Insulators Stabilized by Tungsten Diselenide","authors":"Jing Ding, Hanxiao Xiang, Jiannan Hua, Wenqiang Zhou, Naitian Liu, Le Zhang, Na Xin, Bing Wu, Kenji Watanabe, Takashi Taniguchi, Zdeněk Sofer, Wei Zhu, Shuigang Xu","doi":"10.1103/physrevx.15.011052","DOIUrl":"https://doi.org/10.1103/physrevx.15.011052","url":null,"abstract":"Chern insulators host topologically protected chiral edge currents with quantized conductance characterized by their Chern number. Switching the chirality of a Chern insulator, namely, the direction of the edge current, is highly challenging due to topologically forbidden backscattering but is of considerable importance for the design of topological devices. Nevertheless, this can be achieved by reversing the sign of the Chern number. Here, we report electrically switchable chirality in rhombohedral multilayer graphene-based Chern insulators through a topological phase transition. By introducing moiré superlattices in rhombohedral heptalayer graphene, we observe a cascade of topological phase transitions at quarter electron filling of a moiré band with the Chern number tunable from −</a:mo>1</a:mn></a:mrow></a:math>, 1, to 2. Furthermore, integrating monolayer tungsten diselenide at the moiréless interface of rhombohedral decalayer graphene and hexagonal boron nitride superlattices stabilizes the Chern insulators, enabling quantized anomalous Hall resistance of <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mi>h</c:mi><c:mo stretchy=\"false\">/</c:mo><c:mn>2</c:mn><c:msup><c:mi>e</c:mi><c:mn>2</c:mn></c:msup></c:mrow></c:math>. Remarkably, the Chern number can be electrically switched using displacement fields, leading to a topological phase transition from <f:math xmlns:f=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><f:mrow><f:mo>−</f:mo><f:mn>1</f:mn></f:mrow></f:math> to 2. Our work establishes rhombohedral multilayer graphene moiré superlattices as a versatile platform for topological engineering, with switchable chirality offering significant promise for integrating chiral edge currents into topological electronic circuits. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"31 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143589807","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}

{"title":"Exploring Atom-Ion Feshbach Resonances below the s -Wave Limit","authors":"Fabian Thielemann, Joachim Siemund, Daniel von Schoenfeld, Wei Wu, Pascal Weckesser, Krzysztof Jachymski, Thomas Walker, Tobias Schaetz","doi":"10.1103/physrevx.15.011051","DOIUrl":"https://doi.org/10.1103/physrevx.15.011051","url":null,"abstract":"Hybrid systems of single, trapped ions embedded in quantum gases are a promising platform for quantum simulations and the study of long-range interactions in the ultracold regime. Feshbach resonances allow for experimental control over the character and strength of the atom-ion interaction. However, the complexity of atom-ion Feshbach spectra, e.g., due to second-order spin-orbit coupling, requires a detailed experimental understanding of the resonance properties—such as the contributing open-channel partial waves. In this work, we immerse a single barium (Ba</a:mi></a:mrow>+</a:mo></a:mrow></a:msup></a:mrow></a:math>) ion in a bath of lithium (Li) atoms spin polarized in their hyperfine ground state to investigate the collision energy dependence of magnetically tunable atom-ion Feshbach resonances. We demonstrate fine control over the kinetic energy of the <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:msup><c:mrow><c:mi>Ba</c:mi></c:mrow><c:mrow><c:mo>+</c:mo></c:mrow></c:msup></c:mrow></c:math> ion and employ it to explore three-body recombination in the transition from the many- to the few-partial wave regime, marked by a sudden increase of resonant loss. In a dense spectrum—with on average 0.58(1) resonances per Gauss—we select a narrow, isolated feature and characterize it as an <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mi>s</e:mi></e:math>-wave resonance. We introduce a quantum recombination model that allows us to distinguish it from higher-partial-wave resonances. Furthermore, in a magnetic field range with no significant loss at the lowest collision energies, we identify a higher-partial-wave resonance that appears and peaks only when we increase the energy to around the <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mi>s</g:mi></g:math>-wave limit. Our results demonstrate that hybrid atom-ion traps can reach collision energies well in the ultracold regime and that the ion’s kinetic energy can be employed to tune the collisional complex to resonance, paving the way for fast control over the interaction in settings where magnetic field variations are detrimental to coherence. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"584 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143575211","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}

{"title":"Confined Trions and Mott-Wigner States in a Purely Electrostatic Moiré Potential","authors":"Natasha Kiper, Haydn S. Adlong, Arthur Christianen, Martin Kroner, Kenji Watanabe, Takashi Taniguchi, Atac İmamoğlu","doi":"10.1103/physrevx.15.011049","DOIUrl":"https://doi.org/10.1103/physrevx.15.011049","url":null,"abstract":"Moiré heterostructures consisting of transition metal dichalcogenide (TMD) heterobilayers and homobilayers have emerged as a promising material platform to study correlated electronic states. Optical signatures of strong correlations in the form of Mott-Wigner states and fractional Chern insulators have already been observed in TMD monolayers and their twisted bilayers. In this work, we use a moiré substrate containing a twisted hexagonal boron nitride (h</a:mi></a:mrow></a:math>-BN) interface to externally generate a superlattice potential for the TMD layer: The periodic structure of ferroelectric domains in <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mi>h</c:mi></c:mrow></c:math>-BN creates a purely electrostatic potential for charge carriers. We find direct evidence for the induced moiré potential in the emergence of new excitonic resonances at integer fillings and our observation of an enhancement of the trion binding energy by <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mo>≃</e:mo><e:mn>3</e:mn><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>meV</e:mi></e:mrow></e:math>. A theoretical model for exciton-electron interactions allows us to directly determine the moiré potential modulation of <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mn>30</g:mn><g:mo>±</g:mo><g:mn>5</g:mn><g:mtext> </g:mtext><g:mtext> </g:mtext><g:mi>meV</g:mi></g:math> from the measured trion binding energy shift. We obtain direct evidence for charge order linked to electronic Mott-Wigner states at filling factors <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><i:mi>ν</i:mi><i:mo>=</i:mo><i:mn>1</i:mn><i:mo>/</i:mo><i:mn>3</i:mn></i:math> and <k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><k:mi>ν</k:mi><k:mo>=</k:mo><k:mn>2</k:mn><k:mo>/</k:mo><k:mn>3</k:mn></k:math> through the associated exciton umklapp resonances. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"67 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143569702","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}

{"title":"Optical Absorption Spectroscopy Probes Water Wire and Its Ordering in a Hydrogen-Bond Network","authors":"Fujie Tang, Diana Y. Qiu, Xifan Wu","doi":"10.1103/physrevx.15.011048","DOIUrl":"https://doi.org/10.1103/physrevx.15.011048","url":null,"abstract":"Water wires, quasi-one-dimensional chains composed of hydrogen-bonded (H-bonded) water molecules, play a fundamental role in numerous chemical, physical, and physiological processes. Yet direct experimental detection of water wires has been elusive so far. Based on advanced many-body theory that includes electron-hole interactions, we report that optical absorption spectroscopy can serve as a sensitive probe of water wires and their ordering. In both liquid and solid water, the main peak of the spectrum is discovered to be a charge-transfer exciton. In water, the charge-transfer exciton is strongly coupled to the H-bonding environment where the exciton is excited between H-bonded water molecules with a large spectral intensity. In regular ice, the spectral weight of the charge-transfer exciton is enhanced by a collective excitation occurring on proton-ordered water wires, whose spectral intensity scales with the ordering length of water wire. The spectral intensity and excitonic interaction strength reaches its maximum in ice XI, where the long-range ordering length yields the most pronounced spectral signal. Our findings suggest that water wires, which widely exist in important physiological and biological systems and other phases of ice, can be directly probed by this approach. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"37 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143570290","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}

{"title":"Spin Seebeck Effect as a Probe for Majorana Fermions in Kitaev Spin Liquids","authors":"Yasuyuki Kato, Joji Nasu, Masahiro Sato, Tsuyoshi Okubo, Takahiro Misawa, Yukitoshi Motome","doi":"10.1103/physrevx.15.011050","DOIUrl":"https://doi.org/10.1103/physrevx.15.011050","url":null,"abstract":"Quantum entanglement in strongly correlated electron systems often leads to exotic elementary excitations. Quantum spin liquids provide a paradigmatic example, where the elementary excitations are described by fractional quasiparticles such as spinons. However, such fractional quasiparticles behave differently from electrons, making their experimental identification challenging. Here, we theoretically investigate the spin Seebeck effect, which is a thermoelectric response via a spin current, as an efficient probe of the fractional quasiparticles in quantum spin liquids, focusing on the Kitaev honeycomb model. By comprehensive studies using real-time dynamics, perturbation theory, and linear spin-wave theory based on the tunnel spin-current theory, we find that the spin current is induced by thermal gradient in the Kitaev spin liquid via the low-energy fractional Majorana excitations. This identification underscores the ability of Majorana fermions to carry spin current, despite lacking spin angular momentum. Furthermore, we find that the induced spin current changes its sign depending on the sign of the Kitaev interaction, indicating that the Majorana fermions contribute to the spin current with (up-) down-spin-like nature when the exchange coupling is (anti)ferromagnetic. Thus, in contrast to the negative spin current already found in a one-dimensional quantum spin liquid, our calculation reveals that the spin Seebeck effect can exhibit either positive or negative signals, contingent upon the nature of fractional excitations in the quantum spin liquids. We also clarify contrasting field-angle dependence between the Kitaev spin liquid in the low-field limit and the high-field ferromagnetic state, which is useful for the experimental identification. Our finding suggests that the spin Seebeck effect could be used not only to detect fractional quasiparticles emerging in quantum spin liquids but also to generate and control them. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"85 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143569740","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}