Pub Date : 2024-09-20DOI: 10.1103/physrevx.14.031049
Martina Clairand, Ali Mozaffari, Jerôme Hardoüin, Rui Zhang, Claire Doré, Jordi Ignés-Mullol, Francesc Sagués, Juan J. de Pablo, Teresa Lopez-Leon
We investigate the steady state of an ellipsoidal active nematic shell using experiments and numerical simulations. We create the shells by coating microsized ellipsoidal droplets with a protein-based active cytoskeletal gel, thus obtaining ellipsoidal core-shell structures. This system provides the appropriate conditions of confinement and geometry to investigate the impact of nonuniform curvature on an orderly active nematic fluid that features the minimum number of defects required by topology. We identify new time-dependent states where topological defects periodically oscillate between translational and rotational regimes, resulting in the spontaneous emergence of chirality. Our simulations of active nematohydrodynamics demonstrate that, beyond topology and activity, the dynamics of the active material are profoundly influenced by the local curvature and viscous anisotropy of the underlying droplet, as well as by external hydrodynamic forces stemming from the self-sustained rotational motion of defects. These results illustrate how the incorporation of curvature gradients into active nematic shells orchestrates remarkable spatiotemporal patterns, offering new insights into biological processes and providing compelling prospects for designing bioinspired micromachines.
{"title":"Dynamics of Active Defects on the Anisotropic Surface of an Ellipsoidal Droplet","authors":"Martina Clairand, Ali Mozaffari, Jerôme Hardoüin, Rui Zhang, Claire Doré, Jordi Ignés-Mullol, Francesc Sagués, Juan J. de Pablo, Teresa Lopez-Leon","doi":"10.1103/physrevx.14.031049","DOIUrl":"https://doi.org/10.1103/physrevx.14.031049","url":null,"abstract":"We investigate the steady state of an ellipsoidal active nematic shell using experiments and numerical simulations. We create the shells by coating microsized ellipsoidal droplets with a protein-based active cytoskeletal gel, thus obtaining ellipsoidal core-shell structures. This system provides the appropriate conditions of confinement and geometry to investigate the impact of nonuniform curvature on an orderly active nematic fluid that features the minimum number of defects required by topology. We identify new time-dependent states where topological defects periodically oscillate between translational and rotational regimes, resulting in the spontaneous emergence of chirality. Our simulations of active nematohydrodynamics demonstrate that, beyond topology and activity, the dynamics of the active material are profoundly influenced by the local curvature and viscous anisotropy of the underlying droplet, as well as by external hydrodynamic forces stemming from the self-sustained rotational motion of defects. These results illustrate how the incorporation of curvature gradients into active nematic shells orchestrates remarkable spatiotemporal patterns, offering new insights into biological processes and providing compelling prospects for designing bioinspired micromachines.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"17 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276005","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 : 2024-09-17DOI: 10.1103/physrevx.14.031047
Abel J. Abraham, Stepan Malkov, Frane A. Ljubetic, Matthew Durey, Pedro J. Sáenz
Understanding the ability of particles to maneuver through disordered environments is a central problem in innumerable settings, from active matter and biology to electronics. Macroscopic particles ultimately exhibit diffusive motion when their energy exceeds the characteristic potential barrier of the random landscape. In stark contrast, wave-particle duality causes electrons in disordered media to come to rest even when the potential is weak—a remarkable phenomenon known as Anderson localization. Here, we present a hydrodynamic active system with wave-particle features, a millimetric droplet self-guided by its own wave field over a submerged random topography, whose dynamics exhibits localized statistics analogous to those of electronic systems. Consideration of an ensemble of particle trajectories reveals a suppression of diffusion when the guiding wave field extends over the disordered topography. We rationalize mechanistically the emergent statistics by virtue of the wave-mediated resonant coupling between the droplet and topography, which produces an attractive wave potential about the localization region. This hydrodynamic analog, which demonstrates how a classical particle may localize like a wave, suggests new directions for future research in various areas, including active matter, wave localization, many-body localization, and topological matter.
{"title":"Anderson Localization of Walking Droplets","authors":"Abel J. Abraham, Stepan Malkov, Frane A. Ljubetic, Matthew Durey, Pedro J. Sáenz","doi":"10.1103/physrevx.14.031047","DOIUrl":"https://doi.org/10.1103/physrevx.14.031047","url":null,"abstract":"Understanding the ability of particles to maneuver through disordered environments is a central problem in innumerable settings, from active matter and biology to electronics. Macroscopic particles ultimately exhibit diffusive motion when their energy exceeds the characteristic potential barrier of the random landscape. In stark contrast, wave-particle duality causes electrons in disordered media to come to rest even when the potential is weak—a remarkable phenomenon known as Anderson localization. Here, we present a hydrodynamic active system with wave-particle features, a millimetric droplet self-guided by its own wave field over a submerged random topography, whose dynamics exhibits localized statistics analogous to those of electronic systems. Consideration of an ensemble of particle trajectories reveals a suppression of diffusion when the guiding wave field extends over the disordered topography. We rationalize mechanistically the emergent statistics by virtue of the wave-mediated resonant coupling between the droplet and topography, which produces an attractive wave potential about the localization region. This hydrodynamic analog, which demonstrates how a classical particle may localize like a wave, suggests new directions for future research in various areas, including active matter, wave localization, many-body localization, and topological matter.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"53 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235151","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 : 2024-09-17DOI: 10.1103/physrevx.14.031048
F. H. L. Essler, A. J. J. M. de Klerk
We study the statistics of matrix elements of local operators in the basis of energy eigenstates in a paradigmatic, integrable, many-particle quantum theory, the Lieb-Liniger model of bosons with repulsive delta-function interactions. Using methods of quantum integrability, we determine the scaling of matrix elements with system size. As a consequence of the extensive number of conservation laws, the structure of matrix elements is fundamentally different from, and much more intricate than, the predictions of the eigenstate thermalization hypothesis for generic models. We uncover an interesting connection between this structure for local operators in interacting integrable models and the one for local operators that are not local with respect to the elementary excitations in free theories. We find that typical off-diagonal matrix elements in the same macrostate scale as , where the probability distribution function for is well described by Fréchet distributions and depends only on macrostate information. In contrast, typical off-diagonal matrix elements between two different macrostates scale as , where depends only on macrostate information. Diagonal matrix elements depend only on macrostate information up to finite-size corrections.
我们研究了一个典型的、可积分的多粒子量子理论--具有排斥性三角函数相互作用的玻色子的利布-利尼格模型--中的能量特征状态基础上的局部算子矩阵元素的统计。利用量子可积分性方法，我们确定了矩阵元素随系统规模的缩放。由于存在大量的守恒定律，矩阵元素的结构与一般模型的特征态热化假说的预测有着本质的区别，而且更为复杂。我们发现了相互作用可积分模型中局部算子的这种结构与自由理论中与基本激元无关的局部算子的这种结构之间的有趣联系。我们发现，典型的非对角矩阵元素⟨μ|O|λ⟩在同一宏观状态尺度上与exp(-cOLln(L)-LMμ,λO)相同，其中Mμ,λO的概率分布函数由弗雷谢特分布很好地描述，而cO只取决于宏观状态信息。相反，两个不同宏观状态之间的典型非对角矩阵元素的规模为 exp(-dOL2)，其中 dO 仅取决于宏观状态信息。对角线矩阵元素只取决于宏观状态信息，直至有限尺寸修正。
{"title":"Statistics of Matrix Elements of Local Operators in Integrable Models","authors":"F. H. L. Essler, A. J. J. M. de Klerk","doi":"10.1103/physrevx.14.031048","DOIUrl":"https://doi.org/10.1103/physrevx.14.031048","url":null,"abstract":"We study the statistics of matrix elements of local operators in the basis of energy eigenstates in a paradigmatic, integrable, many-particle quantum theory, the Lieb-Liniger model of bosons with repulsive delta-function interactions. Using methods of quantum integrability, we determine the scaling of matrix elements with system size. As a consequence of the extensive number of conservation laws, the structure of matrix elements is fundamentally different from, and much more intricate than, the predictions of the eigenstate thermalization hypothesis for generic models. We uncover an interesting connection between this structure for local operators in interacting integrable models and the one for local operators that are not local with respect to the elementary excitations in free theories. We find that typical off-diagonal matrix elements <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">⟨</mo><mi mathvariant=\"bold-italic\">μ</mi><mo stretchy=\"false\">|</mo><mi mathvariant=\"script\">O</mi><mo stretchy=\"false\">|</mo><mi mathvariant=\"bold-italic\">λ</mi><mo stretchy=\"false\">⟩</mo></math> in the same macrostate scale as <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>exp</mi><mo mathvariant=\"bold\" stretchy=\"false\">(</mo><mo>−</mo><msup><mrow><mi>c</mi></mrow><mrow><mi mathvariant=\"script\">O</mi></mrow></msup><mi>L</mi><mi>ln</mi><mo stretchy=\"false\">(</mo><mi>L</mi><mo stretchy=\"false\">)</mo><mo>−</mo><mi>L</mi><msubsup><mrow><mi>M</mi></mrow><mrow><mi mathvariant=\"bold-italic\">μ</mi><mo>,</mo><mi mathvariant=\"bold-italic\">λ</mi></mrow><mrow><mi mathvariant=\"script\">O</mi></mrow></msubsup><mo mathvariant=\"bold\" stretchy=\"false\">)</mo></mrow></math>, where the probability distribution function for <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msubsup><mi>M</mi><mrow><mi mathvariant=\"bold-italic\">μ</mi><mo>,</mo><mi mathvariant=\"bold-italic\">λ</mi></mrow><mi mathvariant=\"script\">O</mi></msubsup></math> is well described by Fréchet distributions and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>c</mi><mi mathvariant=\"script\">O</mi></msup></math> depends only on macrostate information. In contrast, typical off-diagonal matrix elements between two different macrostates scale as <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>exp</mi><mo stretchy=\"false\">(</mo><mo>−</mo><msup><mi>d</mi><mi mathvariant=\"script\">O</mi></msup><msup><mi>L</mi><mn>2</mn></msup><mo stretchy=\"false\">)</mo></math>, where <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>d</mi><mi mathvariant=\"script\">O</mi></msup></math> depends only on macrostate information. Diagonal matrix elements depend only on macrostate information up to finite-size corrections.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"6 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235124","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 : 2024-09-16DOI: 10.1103/physrevx.14.031046
Rodrigo Gutiérrez-Cuevas, Arthur Goetschy, Yaron Bromberg, Guy Pelc, Esben Ravn Andresen, Laurent Bigot, Yves Quiquempois, Maroun Bsaibes, Pierre Sillard, Marianne Bigot, Ori Katz, Julien de Rosny, Sébastien M. Popoff
In an ideal perfectly straight multimode fiber with a circular core, the symmetry ensures that rotating the input wave front leads to a corresponding rotation of the output wave front. This invariant property, known as the rotational memory effect (RME), remains independent of the typically unknown output profile. The RME thus offers significant potential for imaging and telecommunication applications. However, in real-life fibers, this effect is degraded by intrinsic imperfections and external perturbations, and is challenging to observe because of its acute sensitivity to misalignments and aberrations in the optical setup. Building on a previously established method for precisely estimating fiber transmission properties, we demonstrate an accurate extraction of RME properties. Additionally, we introduce a comprehensive theoretical framework for both qualitative and quantitative analysis, which specifically links the angular-dependent correlation of the RME to the core deformation’s geometrical properties and the fiber’s mode characteristics. Our theoretical predictions align well with experimental data and simulations for various amounts of fiber distorsion. Finally, we demonstrate the ability to engineer wave fronts with significantly enhanced correlation across all rotation angles. This work enables accurate characterization of distributed disorder from the fabrication process and facilitates calibration-free imaging in multimode fibers.
{"title":"Characterization and Exploitation of the Rotational Memory Effect in Multimode Fibers","authors":"Rodrigo Gutiérrez-Cuevas, Arthur Goetschy, Yaron Bromberg, Guy Pelc, Esben Ravn Andresen, Laurent Bigot, Yves Quiquempois, Maroun Bsaibes, Pierre Sillard, Marianne Bigot, Ori Katz, Julien de Rosny, Sébastien M. Popoff","doi":"10.1103/physrevx.14.031046","DOIUrl":"https://doi.org/10.1103/physrevx.14.031046","url":null,"abstract":"In an ideal perfectly straight multimode fiber with a circular core, the symmetry ensures that rotating the input wave front leads to a corresponding rotation of the output wave front. This invariant property, known as the rotational memory effect (RME), remains independent of the typically unknown output profile. The RME thus offers significant potential for imaging and telecommunication applications. However, in real-life fibers, this effect is degraded by intrinsic imperfections and external perturbations, and is challenging to observe because of its acute sensitivity to misalignments and aberrations in the optical setup. Building on a previously established method for precisely estimating fiber transmission properties, we demonstrate an accurate extraction of RME properties. Additionally, we introduce a comprehensive theoretical framework for both qualitative and quantitative analysis, which specifically links the angular-dependent correlation of the RME to the core deformation’s geometrical properties and the fiber’s mode characteristics. Our theoretical predictions align well with experimental data and simulations for various amounts of fiber distorsion. Finally, we demonstrate the ability to engineer wave fronts with significantly enhanced correlation across all rotation angles. This work enables accurate characterization of distributed disorder from the fabrication process and facilitates calibration-free imaging in multimode fibers.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"44 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235123","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 : 2024-09-11DOI: 10.1103/physrevx.14.031045
Gautam Rai, Lorenzo Crippa, Dumitru Călugăru, Haoyu Hu, Francesca Paoletti, Luca de’ Medici, Antoine Georges, B. Andrei Bernevig, Roser Valentí, Giorgio Sangiovanni, Tim Wehling
The interplay of dynamical correlations and electronic ordering is pivotal in shaping phase diagrams of correlated quantum materials. In magic-angle twisted bilayer graphene, transport, thermodynamic, and spectroscopic experiments pinpoint a competition between distinct low-energy states with and without electronic order, as well as between localized and delocalized charge carriers. In this study, we utilize dynamical mean-field theory on the topological heavy fermion model of twisted bilayer graphene to investigate the emergence of electronic correlations and long-range order in the absence of strain. We contrast moment formation, Kondo screening, and ordering on a temperature basis and explain the nature of emergent correlated states based on three central phenomena: (i) the formation of local spin and valley isospin moments around 100 K, (ii) the ordering of the local isospin moments around 10 K preempting Kondo screening, and (iii) a cascadic redistribution of charge between localized and delocalized electronic states upon doping. At integer fillings, we find that low-energy spectral weight is depleted in the symmetric phase, while we find insulating states with gaps enhanced by exchange coupling in the zero-strain ordered phases. Doping away from integer filling results in distinct metallic states: a “bad metal” above the ordering temperature, where scattering off the disordered local moments suppresses electronic coherence, and a “good metal” in the ordered states with coherence of quasiparticles facilitated by isospin order. This finding reveals coherence from order as the microscopic mechanism behind the Pomeranchuk effect observed experimentally by Rozen et al. [Nature (London)592, 214 (2021)] and by Saito et al. [Nature (London)592, 220 (2021)]. Upon doping, there is a periodic charge reshuffling between localized and delocalized electronic orbitals leading to cascades of doping-induced Lifshitz transitions, local spectral weight redistributions, and periodic variations of the electronic compressibility ranging from nearly incompressible to negative. Our findings highlight the essential role of charge transfer, hybridization, and ordering in shaping the electronic excitations and thermodynamic properties in twisted bilayer graphene and provide a unified understanding of the most puzzling aspects of scanning tunneling spectroscopy, transport, and compressibility experiments.
{"title":"Dynamical Correlations and Order in Magic-Angle Twisted Bilayer Graphene","authors":"Gautam Rai, Lorenzo Crippa, Dumitru Călugăru, Haoyu Hu, Francesca Paoletti, Luca de’ Medici, Antoine Georges, B. Andrei Bernevig, Roser Valentí, Giorgio Sangiovanni, Tim Wehling","doi":"10.1103/physrevx.14.031045","DOIUrl":"https://doi.org/10.1103/physrevx.14.031045","url":null,"abstract":"The interplay of dynamical correlations and electronic ordering is pivotal in shaping phase diagrams of correlated quantum materials. In magic-angle twisted bilayer graphene, transport, thermodynamic, and spectroscopic experiments pinpoint a competition between distinct low-energy states with and without electronic order, as well as between localized and delocalized charge carriers. In this study, we utilize dynamical mean-field theory on the topological heavy fermion model of twisted bilayer graphene to investigate the emergence of electronic correlations and long-range order in the absence of strain. We contrast moment formation, Kondo screening, and ordering on a temperature basis and explain the nature of emergent correlated states based on three central phenomena: (i) the formation of local spin and valley isospin moments around 100 K, (ii) the ordering of the local isospin moments around 10 K preempting Kondo screening, and (iii) a cascadic redistribution of charge between localized and delocalized electronic states upon doping. At integer fillings, we find that low-energy spectral weight is depleted in the symmetric phase, while we find insulating states with gaps enhanced by exchange coupling in the zero-strain ordered phases. Doping away from integer filling results in distinct metallic states: a “bad metal” above the ordering temperature, where scattering off the disordered local moments suppresses electronic coherence, and a “good metal” in the ordered states with coherence of quasiparticles facilitated by isospin order. This finding reveals coherence from order as the microscopic mechanism behind the Pomeranchuk effect observed experimentally by Rozen <i>et al.</i> [<span>Nature (London)</span> <b>592</b>, 214 (2021)] and by Saito <i>et al.</i> [<span>Nature (London)</span> <b>592</b>, 220 (2021)]. Upon doping, there is a periodic charge reshuffling between localized and delocalized electronic orbitals leading to cascades of doping-induced Lifshitz transitions, local spectral weight redistributions, and periodic variations of the electronic compressibility ranging from nearly incompressible to negative. Our findings highlight the essential role of charge transfer, hybridization, and ordering in shaping the electronic excitations and thermodynamic properties in twisted bilayer graphene and provide a unified understanding of the most puzzling aspects of scanning tunneling spectroscopy, transport, and compressibility experiments.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"17 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142170820","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 : 2024-09-10DOI: 10.1103/physrevx.14.031044
Shengqi Sang, Yijian Zou, Timothy H. Hsieh
Open system quantum dynamics can generate a variety of long-range entangled mixed states, yet it has been unclear in what sense they constitute phases of matter. To establish that two mixed states are in the same phase, as defined by their two-way connectivity via local quantum channels, we use the renormalization group (RG) and decoders of quantum error correcting codes. We introduce a real-space RG scheme for mixed states based on local channels which ideally preserve correlations with the complementary system, and we prove this is equivalent to the reversibility of the channel’s action. As an application, we demonstrate an exact RG flow of finite temperature toric code in two dimensions to infinite temperature, thus proving it is in the trivial phase. In contrast, for toric code subject to local dephasing, we establish a mixed-state toric code phase using local channels obtained by truncating an RG-type decoder and the minimum weight perfect matching decoder. We also discover a precise relation between mixed-state phase and decodability, by proving that local noise acting on toric code cannot destroy logical information without bringing the state out of the toric code phase.
{"title":"Mixed-State Quantum Phases: Renormalization and Quantum Error Correction","authors":"Shengqi Sang, Yijian Zou, Timothy H. Hsieh","doi":"10.1103/physrevx.14.031044","DOIUrl":"https://doi.org/10.1103/physrevx.14.031044","url":null,"abstract":"Open system quantum dynamics can generate a variety of long-range entangled mixed states, yet it has been unclear in what sense they constitute phases of matter. To establish that two mixed states are in the same phase, as defined by their two-way connectivity via local quantum channels, we use the renormalization group (RG) and decoders of quantum error correcting codes. We introduce a real-space RG scheme for mixed states based on local channels which ideally preserve correlations with the complementary system, and we prove this is equivalent to the reversibility of the channel’s action. As an application, we demonstrate an exact RG flow of finite temperature toric code in two dimensions to infinite temperature, thus proving it is in the trivial phase. In contrast, for toric code subject to local dephasing, we establish a mixed-state toric code phase using local channels obtained by truncating an RG-type decoder and the minimum weight perfect matching decoder. We also discover a precise relation between mixed-state phase and decodability, by proving that local noise acting on toric code cannot destroy logical information without bringing the state out of the toric code phase.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"103 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160421","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 : 2024-09-09DOI: 10.1103/physrevx.14.031043
Kseniia Vodenkova, Hannes Pichler
In this paper, we develop a novel method to solve problems involving quantum optical systems coupled to coherent quantum feedback loops featuring time delays. Our method is based on exact mappings of such non-Markovian problems to equivalent Markovian driven dissipative quantum many-body problems. In this work, we show that the resulting Markovian quantum many-body problems can be solved (numerically) exactly and efficiently using tensor network methods for a series of paradigmatic examples, consisting of driven quantum systems coupled to waveguides at several distant points. In particular, we show that our method allows solving problems in so far inaccessible regimes, including problems with arbitrary long time delays and arbitrary numbers of excitations in the delay lines. We obtain solutions for the full real-time dynamics as well as the steady state in all these regimes. Finally, motivated by our results, we develop a novel mean-field approach, which allows us to find the solution semianalytically, and we identify parameter regimes where this approximation is in excellent agreement with our tensor network results.
{"title":"Continuous Coherent Quantum Feedback with Time Delays: Tensor Network Solution","authors":"Kseniia Vodenkova, Hannes Pichler","doi":"10.1103/physrevx.14.031043","DOIUrl":"https://doi.org/10.1103/physrevx.14.031043","url":null,"abstract":"In this paper, we develop a novel method to solve problems involving quantum optical systems coupled to coherent quantum feedback loops featuring time delays. Our method is based on exact mappings of such non-Markovian problems to equivalent Markovian driven dissipative quantum many-body problems. In this work, we show that the resulting Markovian quantum many-body problems can be solved (numerically) exactly and efficiently using tensor network methods for a series of paradigmatic examples, consisting of driven quantum systems coupled to waveguides at several distant points. In particular, we show that our method allows solving problems in so far inaccessible regimes, including problems with arbitrary long time delays and arbitrary numbers of excitations in the delay lines. We obtain solutions for the full real-time dynamics as well as the steady state in all these regimes. Finally, motivated by our results, we develop a novel mean-field approach, which allows us to find the solution semianalytically, and we identify parameter regimes where this approximation is in excellent agreement with our tensor network results.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"33 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158691","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 : 2024-09-05DOI: 10.1103/physrevx.14.031042
Jonathan G. Hedley, Kush Coshic, Aleksei Aksimentiev, Alexei A. Kornyshev
In solution, DNA, the “most important molecule of life,” is a highly charged macromolecule that bears a unit of negative charge on each phosphate of its sugar-phosphate backbone. Although partially compensated by counterions (cations of the solution) adsorbed at or condensed near it, DNA still produces a substantial electric field in its vicinity, which is screened by buffer electrolytes at longer distances from the DNA. This electric field is experienced by any charged or dipolar species approaching and interacting with the DNA. So far, such a field has been explored predominantly within the scope of a primitive model of the electrolytic solution, not considering more complicated structural effects of the water solvent. In this paper, we investigate the distribution of electric field around DNA using linear response nonlocal electrostatic theory, applied here for helix-specific charge distributions, and compare the predictions of such a theory with specially performed, fully atomistic, large-scale, molecular dynamics simulations. Both approaches are applied to unravel the role of the structure of water at close distances to and within the grooves of a DNA molecule in the formation of the electric field. As predicted by the theory and reported by the simulations, the main finding of this study is that oscillations in the electrostatic potential distribution are present around DNA, caused by the overscreening effect of structured water. Surprisingly, electrolyte ions at physiological concentrations do not strongly disrupt these oscillations and are rather distributed according to these oscillating patterns, indicating that water structural effects dominate the short-range electrostatics. We also show that (i) structured water adsorbed in the grooves of DNA leads to a positive electrostatic potential core relative to the bulk, (ii) the Debye length some 10 Å away from the DNA surface is reduced, effectively renormalized by the helical pitch of the DNA molecule, and (iii) Lorentzian contributions to the nonlocal dielectric function of water, effectively reducing the dielectric constant close to the DNA surface, enhance the overall electric field. The impressive agreement between the atomistic simulations and the developed theory substantiates the use of nonlocal electrostatics when considering solvent effects in molecular processes in biology.
在溶液中，"生命中最重要的分子 "DNA 是一种高电荷大分子，其糖-磷酸骨架的每个磷酸根都带有一个单位的负电荷。尽管 DNA 被吸附在其上或在其附近凝结的反离子（溶液中的阳离子）部分补偿，但仍会在其附近产生一个巨大的电场，该电场被距离 DNA 较远的缓冲电解质所屏蔽。任何接近 DNA 并与之相互作用的带电或偶极物种都会感受到这种电场。迄今为止，人们主要是在电解溶液的原始模型范围内探索这种电场，而没有考虑水溶剂更复杂的结构效应。在本文中，我们利用线性响应非局部静电理论研究了 DNA 周围的电场分布，并将这种理论的预测结果与专门进行的完全原子化的大规模分子动力学模拟进行了比较。这两种方法都用于揭示 DNA 分子沟槽内近距离水的结构在电场形成中的作用。正如理论所预测和模拟所报告的那样，本研究的主要发现是 DNA 周围存在静电势分布振荡，这是由于结构水的超屏蔽效应造成的。令人惊讶的是，生理浓度的电解质离子并没有强烈干扰这些振荡，而是按照这些振荡模式分布，这表明水的结构效应主导了短程静电。我们还表明：(i) DNA 沟槽中吸附的结构水导致了相对于主体的正静电位核；(ii) 距离 DNA 表面约 10 Å 的德拜长度减小了，这实际上是 DNA 分子螺旋间距的重新规范化；(iii) 水的非局部介电函数的洛伦兹贡献有效地减小了靠近 DNA 表面的介电常数，从而增强了整体电场。原子模拟与所建立的理论之间令人印象深刻的一致性证明，在考虑生物分子过程中的溶剂效应时，可以使用非局部静电。
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Pub Date : 2024-09-04DOI: 10.1103/physrevx.14.031041
Kris V. Parag
Quantifying how difficult it is to control an emerging infectious disease is crucial to public health decision-making, providing valuable evidence on if targeted interventions, e.g., quarantine and isolation, can contain spread or when population wide controls, e.g., lockdowns, are warranted. The disease reproduction number or growth rate are universally assumed to measure controllability because and define when infections stop growing and hence the state of critical stability. Outbreaks with larger or are therefore interpreted as less controllable and requiring more stringent interventions. We prove this common interpretation is impractical and incomplete. We identify a positive feedback loop among infections intrinsically underlying disease transmission and evaluate controllability from how interventions disrupt this loop. The epidemic gain and delay margins, which, respectively, define how much we can scale infections (this scaling is known as gain) or delay interventions on this loop before stability is lost, provide rigorous measures of controllability. Outbreaks with smaller margins necessitate more control effort. Using these margins, we quantify how presymptomatic spread, surveillance limitations, variant dynamics, and superspreading shape controllability and demonstrate that and measure controllability only when interventions do not alter timings between the infections and are implemented without delay. Our margins are easily computed, interpreted, and reflect complex relationships among interventions, their implementation, and epidemiological dynamics.
量化控制新发传染病的难度对于公共卫生决策至关重要，它提供了有价值的证据，说明检疫和隔离等有针对性的干预措施是否能遏制传播，或何时需要进行全人群控制，如封锁。疾病繁殖数 R 或增长率 r 被普遍假定为衡量可控性的指标，因为 R=1 和 r=0 定义了感染停止增长的时间，也就是临界稳定状态。因此，R 或 r 越大的疫情被解释为可控性越差，需要更严格的干预措施。我们证明了这种常见的解释是不切实际和不全面的。我们确定了疾病传播内在的感染之间的正反馈循环，并从干预措施如何破坏这一循环来评估可控性。流行病增益边际和延迟边际分别定义了在失去稳定性之前，我们能在多大程度上扩大感染规模（这种扩大被称为增益）或延迟对这一循环的干预，它们为可控性提供了严格的衡量标准。裕度越小的疫情爆发越需要更多的控制努力。利用这些边际值，我们量化了无症状传播、监控限制、变异动态和超级传播是如何影响可控性的，并证明只有当干预措施不改变感染之间的时间间隔且无延迟实施时，R 和 r 才能衡量可控性。我们的边际值易于计算和解释，并能反映干预措施、其实施和流行病学动态之间的复杂关系。
{"title":"How to Measure the Controllability of an Infectious Disease?","authors":"Kris V. Parag","doi":"10.1103/physrevx.14.031041","DOIUrl":"https://doi.org/10.1103/physrevx.14.031041","url":null,"abstract":"Quantifying how difficult it is to control an emerging infectious disease is crucial to public health decision-making, providing valuable evidence on if targeted interventions, e.g., quarantine and isolation, can contain spread or when population wide controls, e.g., lockdowns, are warranted. The disease reproduction number <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> or growth rate <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>r</mi></math> are universally assumed to measure controllability because <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>R</mi><mo>=</mo><mn>1</mn></mrow></math> and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>r</mi><mo>=</mo><mn>0</mn></mrow></math> define when infections stop growing and hence the state of critical stability. Outbreaks with larger <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> or <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>r</mi></math> are therefore interpreted as less controllable and requiring more stringent interventions. We prove this common interpretation is impractical and incomplete. We identify a positive feedback loop among infections intrinsically underlying disease transmission and evaluate controllability from how interventions disrupt this loop. The epidemic gain and delay margins, which, respectively, define how much we can scale infections (this scaling is known as gain) or delay interventions on this loop before stability is lost, provide rigorous measures of controllability. Outbreaks with smaller margins necessitate more control effort. Using these margins, we quantify how presymptomatic spread, surveillance limitations, variant dynamics, and superspreading shape controllability and demonstrate that <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>r</mi></math> measure controllability only when interventions do not alter timings between the infections and are implemented without delay. Our margins are easily computed, interpreted, and reflect complex relationships among interventions, their implementation, and epidemiological dynamics.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"8 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142130657","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 : 2024-09-03DOI: 10.1103/physrevx.14.031040
Nicholas E. Frattini, Rodrigo G. Cortiñas, Jayameenakshi Venkatraman, Xu Xiao, Qile Su, Chan U. Lei, Benjamin J. Chapman, Vidul R. Joshi, S. M. Girvin, Robert J. Schoelkopf, Shruti Puri, Michel H. Devoret
By applying a microwave drive to a specially designed Josephson circuit, we have realized a double-well model system: a Kerr oscillator submitted to a squeezing force. We have observed, for the first time, the spectroscopic fingerprint of a quantum double-well Hamiltonian when its barrier height is increased: a pairwise level kissing (coalescence) corresponding to the exponential reduction of tunnel splitting in the excited states as they sink under the barrier. The discrete levels in the wells also manifest themselves in the activation time across the barrier which, instead of increasing smoothly as a function of the barrier height, presents steps each time a pair of excited states is captured by the wells. This experiment illustrates the quantum regime of Arrhenius’s law, whose observation is made possible here by the unprecedented combination of low dissipation, time-resolved state control, 98.5% quantum nondemolition single shot measurement fidelity, and complete microwave control over all Hamiltonian parameters in the quantum regime. Direct applications to quantum computation and simulation are discussed.
{"title":"Observation of Pairwise Level Degeneracies and the Quantum Regime of the Arrhenius Law in a Double-Well Parametric Oscillator","authors":"Nicholas E. Frattini, Rodrigo G. Cortiñas, Jayameenakshi Venkatraman, Xu Xiao, Qile Su, Chan U. Lei, Benjamin J. Chapman, Vidul R. Joshi, S. M. Girvin, Robert J. Schoelkopf, Shruti Puri, Michel H. Devoret","doi":"10.1103/physrevx.14.031040","DOIUrl":"https://doi.org/10.1103/physrevx.14.031040","url":null,"abstract":"By applying a microwave drive to a specially designed Josephson circuit, we have realized a double-well model system: a Kerr oscillator submitted to a squeezing force. We have observed, for the first time, the spectroscopic fingerprint of a quantum double-well Hamiltonian when its barrier height is increased: a pairwise level kissing (coalescence) corresponding to the exponential reduction of tunnel splitting in the excited states as they sink under the barrier. The discrete levels in the wells also manifest themselves in the activation time across the barrier which, instead of increasing smoothly as a function of the barrier height, presents steps each time a pair of excited states is captured by the wells. This experiment illustrates the quantum regime of Arrhenius’s law, whose observation is made possible here by the unprecedented combination of low dissipation, time-resolved state control, 98.5% quantum nondemolition single shot measurement fidelity, and complete microwave control over all Hamiltonian parameters in the quantum regime. Direct applications to quantum computation and simulation are discussed.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"6 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123677","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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