首页 > 最新文献

Physical Review X最新文献

英文 中文
Long-Range Entanglement from Measuring Symmetry-Protected Topological Phases 通过测量受对称保护的拓扑相位实现远距离纠缠
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-06-07 DOI: 10.1103/physrevx.14.021040
Nathanan Tantivasadakarn, Ryan Thorngren, Ashvin Vishwanath, Ruben Verresen
A fundamental distinction between many-body quantum states are those with short- and long-range entanglement (SRE and LRE). The latter cannot be created by finite-depth circuits, underscoring the nonlocal nature of Schrödinger cat states, topological order, and quantum criticality. Remarkably, examples are known where LRE is obtained by performing single-site measurements on SRE, such as the toric code from measuring a sublattice of a 2D cluster state. However, a systematic understanding of when and how measurements of SRE give rise to LRE is still lacking. Here, we establish that LRE appears upon performing measurements on symmetry-protected topological (SPT) phases—of which the cluster state is one example. For instance, we show how to implement the Kramers-Wannier transformation by adding a cluster SPT to an input state followed by measurement. This transformation naturally relates states with SRE and LRE. An application is the realization of double-semion order when the input state is the Z2 Levin-Gu SPT. Similarly, the addition of fermionic SPTs and measurement leads to an implementation of the Jordan-Wigner transformation of a general state. More generally, we argue that a large class of SPT phases protected by G×H symmetry gives rise to anomalous LRE upon measuring G-charges, and we prove that this persists for generic points in the SPT phase under certain conditions. Our work introduces a new practical tool for using SPT phases as resources for creating LRE, and we uncover the classification result that all states related by sequentially gauging Abelian groups or by Jordan-Wigner transformation are in the same equivalence class, once we augment finite-depth circuits with single-site measurements. In particular, any topological or fracton order with a solvable finite gauge group can be obtained from a product state in this way.
多体量子态的一个基本区别是具有短程和长程纠缠(SRE 和 LRE)的量子态。后者无法通过有限深度电路产生,这突出了薛定谔猫态、拓扑秩序和量子临界的非局域性。值得注意的是,我们已经知道通过对 SRE 进行单点测量获得 LRE 的例子,例如通过测量二维簇态的子晶格获得环形代码。然而,我们仍然缺乏对 SRE 测量何时以及如何产生 LRE 的系统了解。在这里,我们确定了 LRE 出现在对对称保护拓扑(SPT)相进行测量时--簇态就是一个例子。例如,我们展示了如何通过在输入状态中添加一个簇态 SPT,然后进行测量来实现克拉默-万尼尔变换。这种变换自然地将状态与 SRE 和 LRE 联系起来。当输入态为 Z2 Levin-Gu SPT 时,双海米阶的实现就是一个应用。同样,加入费米子 SPT 和测量,就能实现一般状态的乔丹-维格纳变换。更广义地说,我们认为一大类受 G×H 对称性保护的 SPT 相在测量 G 电荷时会产生反常的 LRE,而且我们证明,在某些条件下,SPT 相中的一般点也会出现这种情况。我们的工作引入了一种新的实用工具,将 SPT 相作为创建 LRE 的资源,并揭示了这样一个分类结果:一旦我们用单点测量增强有限深度电路,所有通过顺序测量阿贝尔群或约旦-维格纳变换相关的状态都属于同一等价类。特别是,任何具有可解有限规整群的拓扑阶或分形阶,都可以通过这种方法从乘积态中获得。
{"title":"Long-Range Entanglement from Measuring Symmetry-Protected Topological Phases","authors":"Nathanan Tantivasadakarn, Ryan Thorngren, Ashvin Vishwanath, Ruben Verresen","doi":"10.1103/physrevx.14.021040","DOIUrl":"https://doi.org/10.1103/physrevx.14.021040","url":null,"abstract":"A fundamental distinction between many-body quantum states are those with short- and long-range entanglement (SRE and LRE). The latter cannot be created by finite-depth circuits, underscoring the nonlocal nature of Schrödinger cat states, topological order, and quantum criticality. Remarkably, examples are known where LRE is obtained by performing single-site measurements on SRE, such as the toric code from measuring a sublattice of a 2D cluster state. However, a systematic understanding of when and how measurements of SRE give rise to LRE is still lacking. Here, we establish that LRE appears upon performing measurements on symmetry-protected topological (SPT) phases—of which the cluster state is one example. For instance, we show how to implement the Kramers-Wannier transformation by adding a cluster SPT to an input state followed by measurement. This transformation naturally relates states with SRE and LRE. An application is the realization of double-semion order when the input state is the <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"double-struck\">Z</mi><mn>2</mn></msub></math> Levin-Gu SPT. Similarly, the addition of fermionic SPTs and measurement leads to an implementation of the Jordan-Wigner transformation of a general state. More generally, we argue that a large class of SPT phases protected by <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>G</mi><mo>×</mo><mi>H</mi></math> symmetry gives rise to anomalous LRE upon measuring <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>G</mi></math>-charges, and we prove that this persists for generic points in the SPT phase under certain conditions. Our work introduces a new practical tool for using SPT phases as resources for creating LRE, and we uncover the classification result that all states related by sequentially gauging Abelian groups or by Jordan-Wigner transformation are in the same equivalence class, once we augment finite-depth circuits with single-site measurements. In particular, any topological or fracton order with a solvable finite gauge group can be obtained from a product state in this way.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141292670","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}
引用次数: 0
Unlearnable Games and “Satisficing” Decisions: A Simple Model for a Complex World 不可学习的游戏与 "满意 "决策:复杂世界的简单模型
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-06-06 DOI: 10.1103/physrevx.14.021039
Jérôme Garnier-Brun, Michael Benzaquen, Jean-Philippe Bouchaud
As a schematic model of the complexity economic agents are confronted with, we introduce the “Sherrington-Kirkpatrick game,” a discrete time binary choice model inspired from mean-field spin glasses. We show that, even in a completely static environment, agents are unable to learn collectively optimal strategies. This is either because the learning process gets trapped in a suboptimal fixed point or because learning never converges and leads to a never-ending evolution of agent intentions. Contrarily to the hope that learning might save the standard “rational expectation” framework in economics, we argue that complex situations are generically unlearnable and agents must do with satisficing solutions, as argued long ago by Simon [Q. J. Econ. 69, 99 (1955)]. Only a centralized, omniscient agent endowed with enormous computing power could qualify to determine the optimal strategy of all agents. Using a mix of analytical arguments and numerical simulations, we find that (i) long memory of past rewards is beneficial to learning, whereas overreaction to recent past is detrimental and leads to cycles or chaos; (ii) increased competition (nonreciprocity) destabilizes fixed points and leads first to chaos and, in the high competition limit, to quasicycles; (iii) some amount of randomness in the learning process, perhaps paradoxically, allows the system to reach better collective decisions; (iv) nonstationary, “aging” behavior spontaneously emerges in a large swath of parameter space of our complex but static world. On the positive side, we find that the learning process allows cooperative systems to coordinate around satisficing solutions with rather high (but markedly suboptimal) average reward. However, hypersensitivity to the game parameters makes it impossible to predict ex ante who will be better or worse off in our stylized economy. The statistical description of the space of satisficing solutions is an open problem.
作为经济行为主体所面临的复杂性的示意模型,我们引入了 "谢林顿-柯克帕特里克博弈",这是一个离散时间二元选择模型,其灵感来自均场自旋眼镜。我们的研究表明,即使在完全静态的环境中,代理人也无法集体学习最优策略。这要么是因为学习过程被困在一个次优的固定点上,要么是因为学习永远不会收敛,导致代理意图永无止境地演化。与学习可能挽救经济学中标准的 "理性预期 "框架的希望相反,我们认为,复杂的情况一般来说是无法学习的,代理人必须采取满足的解决方案,这一点西蒙早就提出过[Q. J. Econ. 69, 99 (1955)]。只有中央集权、无所不知、拥有强大计算能力的代理人才有资格决定所有代理人的最优策略。通过分析论证和数值模拟,我们发现:(i) 对过去回报的长期记忆有利于学习,而对近期回报的过度反应则不利于学习,会导致循环或混乱;(ii) 竞争的加剧(非互惠性)会破坏定点的稳定性,首先导致混乱,在高竞争极限下,会导致准循环;(iii) 学习过程中存在一定的随机性,也许矛盾的是,这种随机性能使系统做出更好的集体决策;(iv) 在我们这个复杂但静态的世界中,参数空间的大片区域自发地出现了非稳态的 "老化 "行为。从积极的方面来看,我们发现学习过程允许合作系统围绕平均回报相当高(但明显低于最优)的满意解决方案进行协调。然而,由于对博弈参数的超敏感性,我们无法事先预测谁会在我们的风格化经济中获得更好或更坏的收益。对满意方案空间的统计描述是一个悬而未决的问题。
{"title":"Unlearnable Games and “Satisficing” Decisions: A Simple Model for a Complex World","authors":"Jérôme Garnier-Brun, Michael Benzaquen, Jean-Philippe Bouchaud","doi":"10.1103/physrevx.14.021039","DOIUrl":"https://doi.org/10.1103/physrevx.14.021039","url":null,"abstract":"As a schematic model of the complexity economic agents are confronted with, we introduce the “Sherrington-Kirkpatrick game,” a discrete time binary choice model inspired from mean-field spin glasses. We show that, even in a completely static environment, agents are unable to learn collectively optimal strategies. This is either because the learning process gets trapped in a suboptimal fixed point or because learning never converges and leads to a never-ending evolution of agent intentions. Contrarily to the hope that learning might save the standard “rational expectation” framework in economics, we argue that complex situations are generically <i>unlearnable</i> and agents must do with <i>satisficing</i> solutions, as argued long ago by Simon [<span>Q. J. Econ.</span> <b>69</b>, 99 (1955)]. Only a centralized, omniscient agent endowed with enormous computing power could qualify to determine the optimal strategy of all agents. Using a mix of analytical arguments and numerical simulations, we find that (i) long memory of past rewards is beneficial to learning, whereas overreaction to recent past is detrimental and leads to cycles or chaos; (ii) increased competition (nonreciprocity) destabilizes fixed points and leads first to chaos and, in the high competition limit, to quasicycles; (iii) some amount of randomness in the learning process, perhaps paradoxically, allows the system to reach better collective decisions; (iv) nonstationary, “aging” behavior spontaneously emerges in a large swath of parameter space of our complex but static world. On the positive side, we find that the learning process allows cooperative systems to coordinate around satisficing solutions with rather high (but markedly suboptimal) average reward. However, hypersensitivity to the game parameters makes it impossible to predict <i>ex ante</i> who will be better or worse off in our stylized economy. The statistical description of the space of satisficing solutions is an open problem.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141264990","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}
引用次数: 0
Testing the Renormalization of the von Klitzing Constant by Cavity Vacuum Fields 用空腔真空场测试冯-克里琴常数的正则化
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-06-05 DOI: 10.1103/physrevx.14.021038
Josefine Enkner, Lorenzo Graziotto, Felice Appugliese, Vasil Rokaj, Jie Wang, Michael Ruggenthaler, Christian Reichl, Werner Wegscheider, Angel Rubio, Jérôme Faist
The value of fundamental physical constants is affected by the coupling of matter to the electromagnetic vacuum state, as predicted and explained by quantum electrodynamics. In this work, we present a millikelvin magnetotransport experiment in the quantum Hall regime that assesses the possibility of the von Klitzing constant being modified by strong cavity vacuum fields. By employing a Wheatstone bridge, we measure the difference between the quantized Hall resistance of a cavity-embedded Hall bar and the resistance standard, achieving an accuracy down to one part in 105 for the lowest Landau level. While our results do not suggest any deviation that could imply a modified Hall resistance, our work represents pioneering efforts in exploring the fundamental implications of vacuum fields in solid-state systems.
正如量子电动力学所预测和解释的那样,基本物理常数的值受物质与电磁真空状态耦合的影响。在这项工作中,我们提出了量子霍尔机制下的毫开尔文磁传输实验,以评估冯-克里琴常数被强空腔真空场改变的可能性。通过使用惠斯通电桥,我们测量了嵌入空腔的霍尔条的量子化霍尔电阻与电阻标准之间的差异,在最低朗道电平上实现了低至 105 分之一的精度。虽然我们的结果并没有显示出任何可能意味着修改过的霍尔电阻的偏差,但我们的工作代表了在探索固态系统中真空场的基本影响方面的开创性努力。
{"title":"Testing the Renormalization of the von Klitzing Constant by Cavity Vacuum Fields","authors":"Josefine Enkner, Lorenzo Graziotto, Felice Appugliese, Vasil Rokaj, Jie Wang, Michael Ruggenthaler, Christian Reichl, Werner Wegscheider, Angel Rubio, Jérôme Faist","doi":"10.1103/physrevx.14.021038","DOIUrl":"https://doi.org/10.1103/physrevx.14.021038","url":null,"abstract":"The value of fundamental physical constants is affected by the coupling of matter to the electromagnetic vacuum state, as predicted and explained by quantum electrodynamics. In this work, we present a millikelvin magnetotransport experiment in the quantum Hall regime that assesses the possibility of the von Klitzing constant being modified by strong cavity vacuum fields. By employing a Wheatstone bridge, we measure the difference between the quantized Hall resistance of a cavity-embedded Hall bar and the resistance standard, achieving an accuracy down to one part in <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mn>5</mn></msup></math> for the lowest Landau level. While our results do not suggest any deviation that could imply a modified Hall resistance, our work represents pioneering efforts in exploring the fundamental implications of vacuum fields in solid-state systems.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141264844","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}
引用次数: 0
Detection of Approaching Critical Transitions in Natural Systems Driven by Red Noise 检测红色噪声驱动的自然系统中临近的临界转换
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-06-04 DOI: 10.1103/physrevx.14.021037
Andreas Morr, Niklas Boers
Detection of critical slowing down (CSD) is the dominant avenue for anticipating critical transitions from noisy time-series data. Most commonly, changes in variance and lag-1 autocorrelation [AC(1)] are used as CSD indicators. However, these indicators will only produce reliable results if the noise driving the system is white and stationary. In the more realistic case of time-correlated red noise, increasing (decreasing) the correlation of the noise will lead to spurious (masked) alarms for both variance and AC(1). Here, we propose two new methods that can discriminate true CSD from possible changes in the driving noise characteristics. We focus on estimating changes in the linear restoring rate based on Langevin-type dynamics driven by either white or red noise. We assess the capacity of our new estimators to anticipate critical transitions and show that they perform significantly better than other existing methods both for continuous-time and discrete-time models. In addition to conceptual models, we apply our methods to climate model simulations of the termination of the African Humid Period. The estimations rule out spurious signals stemming from nonstationary noise characteristics and reveal a destabilization of the African climate system as the dynamical mechanism underlying this archetype of abrupt climate change in the past.
临界放缓(CSD)检测是从噪声时间序列数据中预测临界转换的主要途径。通常,方差变化和滞后-1 自相关 [AC(1)] 被用作 CSD 指标。然而,这些指标只有在驱动系统的噪声是白色和静止的情况下才能产生可靠的结果。在更现实的时间相关红噪声情况下,噪声相关性的增加(减小)将导致方差和 AC(1) 的虚假(掩蔽)警报。在此,我们提出了两种新方法,可以从驱动噪声特性的可能变化中分辨出真正的 CSD。我们的重点是根据白噪声或红噪声驱动的朗格文型动力学来估计线性恢复率的变化。我们对新估算器预测临界转换的能力进行了评估,结果表明,无论是连续时间模型还是离散时间模型,新估算器的性能都明显优于其他现有方法。除了概念模型,我们还将我们的方法应用于非洲湿润期终止的气候模型模拟。估计结果排除了非平稳噪声特征产生的虚假信号,揭示了非洲气候系统的不稳定性是过去这种气候突变原型的动力机制。
{"title":"Detection of Approaching Critical Transitions in Natural Systems Driven by Red Noise","authors":"Andreas Morr, Niklas Boers","doi":"10.1103/physrevx.14.021037","DOIUrl":"https://doi.org/10.1103/physrevx.14.021037","url":null,"abstract":"Detection of critical slowing down (CSD) is the dominant avenue for anticipating critical transitions from noisy time-series data. Most commonly, changes in variance and lag-1 autocorrelation [AC(1)] are used as CSD indicators. However, these indicators will only produce reliable results if the noise driving the system is white and stationary. In the more realistic case of time-correlated red noise, increasing (decreasing) the correlation of the noise will lead to spurious (masked) alarms for both variance and AC(1). Here, we propose two new methods that can discriminate true CSD from possible changes in the driving noise characteristics. We focus on estimating changes in the linear restoring rate based on Langevin-type dynamics driven by either white or red noise. We assess the capacity of our new estimators to anticipate critical transitions and show that they perform significantly better than other existing methods both for continuous-time and discrete-time models. In addition to conceptual models, we apply our methods to climate model simulations of the termination of the African Humid Period. The estimations rule out spurious signals stemming from nonstationary noise characteristics and reveal a destabilization of the African climate system as the dynamical mechanism underlying this archetype of abrupt climate change in the past.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246485","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}
引用次数: 0
Graph Atomic Cluster Expansion for Semilocal Interactions beyond Equivariant Message Passing 超越等量信息传递的半局部交互的图原子簇扩展
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-06-03 DOI: 10.1103/physrevx.14.021036
Anton Bochkarev, Yury Lysogorskiy, Ralf Drautz
The atomic cluster expansion provides local, complete basis functions that enable efficient parametrization of many-atom interactions. We extend the atomic cluster expansion to incorporate graph basis functions. This naturally leads to representations that enable the efficient description of semilocal interactions in physically and chemically transparent form. Simplification of the graph expansion by tensor decomposition results in an iterative procedure that comprises current message-passing machine learning interatomic potentials. We demonstrate the accuracy and efficiency of the graph atomic cluster expansion for a number of small molecules, clusters, and a general-purpose model for carbon. We further show that the graph atomic cluster expansion scales linearly with the number of neighbors and layer depth of the graph basis functions.
原子簇扩展提供了局部的、完整的基函数,可以高效地对多原子相互作用进行参数化。我们对原子团扩展进行了扩展,纳入了图形基函数。这自然会导致以物理和化学透明的形式有效描述半局部相互作用的表征。通过张量分解来简化图展开,从而产生了一种迭代程序,该程序包括当前的消息传递机器学习原子间势。我们展示了图原子团簇扩展在一些小分子、团簇和通用碳模型中的准确性和效率。我们进一步证明,图原子团簇扩展与图基函数的邻域数和层深度成线性关系。
{"title":"Graph Atomic Cluster Expansion for Semilocal Interactions beyond Equivariant Message Passing","authors":"Anton Bochkarev, Yury Lysogorskiy, Ralf Drautz","doi":"10.1103/physrevx.14.021036","DOIUrl":"https://doi.org/10.1103/physrevx.14.021036","url":null,"abstract":"The atomic cluster expansion provides local, complete basis functions that enable efficient parametrization of many-atom interactions. We extend the atomic cluster expansion to incorporate graph basis functions. This naturally leads to representations that enable the efficient description of semilocal interactions in physically and chemically transparent form. Simplification of the graph expansion by tensor decomposition results in an iterative procedure that comprises current message-passing machine learning interatomic potentials. We demonstrate the accuracy and efficiency of the graph atomic cluster expansion for a number of small molecules, clusters, and a general-purpose model for carbon. We further show that the graph atomic cluster expansion scales linearly with the number of neighbors and layer depth of the graph basis functions.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246641","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}
引用次数: 0
Understanding Inner-Shell Excitations in Molecules through Spectroscopy of the 4f Hole States of YbF 通过对 YbF 的 4f 孔态进行光谱分析了解分子中的内壳激发
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-05-30 DOI: 10.1103/physrevx.14.021035
S. Popa, S. Schaller, A. Fielicke, J. Lim, B. G. Sartakov, M. R. Tarbutt, G. Meijer
Molecules containing a lanthanide atom have sets of electronic states arising from excitation of an inner-shell electron. These states have received little attention but are thought to play an important role in laser cooling of such molecules and may be a useful resource for testing fundamental physics. We study a series of inner-shell excited states in YbF using resonance-enhanced multiphoton ionization spectroscopy. We investigate the excited states of lowest energy, 8474, 9013, and 9090cm1 above the ground state, all corresponding to the configuration 4f136s2F27/2 of the Yb+ ion. They are metastable, since they have no electric dipole allowed transitions to the ground state. We also characterize a state at 31050cm1 that is easily excited from both the ground and metastable states, which makes it especially useful for this spectroscopic study. Finally, we study two states at 48 720 and 48729cm1, which are above the ionization limit and feature strong autoionizing resonances that prove useful for efficient detection of the molecules and for identifying the rotational quantum number of each line in the spectrum. We resolve the rotational structures of all these states and find that they can all be described by a very simple model based on Hund’s case (c). Our study provides information necessary for laser slowing and magneto-optical trapping of YbF, which is an important species for testing fundamental physics. We also consider whether the low-lying inner-shell states may themselves be useful as probes of the electron’s electric dipole moment or of varying fundamental constants, since they are long-lived states in a laser-coolable molecule featuring closely spaced levels of opposite parity.
含有镧系元素原子的分子具有由内壳电子激发产生的电子态。这些状态很少受到关注,但被认为在激光冷却此类分子的过程中发挥着重要作用,并可能成为检验基础物理学的有用资源。我们利用共振增强多光子电离光谱法研究了 YbF 中的一系列内壳激发态。我们研究了能量最低的激发态,即高于基态的 8474、9013 和 9090 cm-1,它们都对应于 Yb+ 离子的构型 4f136s2 F27/2。它们是可转移的,因为它们没有电偶极子允许过渡到基态。我们还描述了 31 050 cm-1 处的一个状态,该状态很容易从基态和逸散态激发出来,因此特别适用于本次光谱研究。最后,我们还研究了 48 720 和 48 729 cm-1 处的两个状态,这两个状态高于电离极限,具有很强的自电离共振,有助于有效地探测分子,并确定光谱中每条线的旋转量子数。我们解析了所有这些状态的旋转结构,发现它们都可以用一个基于 Hund (c) 情况的非常简单的模型来描述。我们的研究为掺镱光纤的激光减速和磁光捕获提供了必要的信息,而掺镱光纤是检验基础物理学的重要物质。我们还考虑了低洼内壳态本身是否可以用来探测电子的电偶极矩或变化的基本常数,因为这些低洼内壳态是激光可冷却分子中的长寿命态,具有间距很近的相反奇偶性水平。
{"title":"Understanding Inner-Shell Excitations in Molecules through Spectroscopy of the 4f Hole States of YbF","authors":"S. Popa, S. Schaller, A. Fielicke, J. Lim, B. G. Sartakov, M. R. Tarbutt, G. Meijer","doi":"10.1103/physrevx.14.021035","DOIUrl":"https://doi.org/10.1103/physrevx.14.021035","url":null,"abstract":"Molecules containing a lanthanide atom have sets of electronic states arising from excitation of an inner-shell electron. These states have received little attention but are thought to play an important role in laser cooling of such molecules and may be a useful resource for testing fundamental physics. We study a series of inner-shell excited states in YbF using resonance-enhanced multiphoton ionization spectroscopy. We investigate the excited states of lowest energy, 8474, 9013, and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>9090</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> above the ground state, all corresponding to the configuration <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>4</mn><msup><mrow><mi>f</mi></mrow><mrow><mn>13</mn></mrow></msup><mn>6</mn><msup><mrow><mi>s</mi></mrow><mrow><mn>2</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msub><mrow><mmultiscripts><mrow><mi>F</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>2</mn></mrow></mmultiscripts></mrow><mrow><mn>7</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math> of the <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mrow><mi>Yb</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math> ion. They are metastable, since they have no electric dipole allowed transitions to the ground state. We also characterize a state at <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>31</mn><mtext> </mtext><mn>050</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> that is easily excited from both the ground and metastable states, which makes it especially useful for this spectroscopic study. Finally, we study two states at 48 720 and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>48</mn><mtext> </mtext><mn>729</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>, which are above the ionization limit and feature strong autoionizing resonances that prove useful for efficient detection of the molecules and for identifying the rotational quantum number of each line in the spectrum. We resolve the rotational structures of all these states and find that they can all be described by a very simple model based on Hund’s case (c). Our study provides information necessary for laser slowing and magneto-optical trapping of YbF, which is an important species for testing fundamental physics. We also consider whether the low-lying inner-shell states may themselves be useful as probes of the electron’s electric dipole moment or of varying fundamental constants, since they are long-lived states in a laser-coolable molecule featuring closely spaced levels of opposite parity.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141182500","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}
引用次数: 0
Glassy Word Problems: Ultraslow Relaxation, Hilbert Space Jamming, and Computational Complexity 玻璃文字问题:超低松弛、希尔伯特空间干扰和计算复杂性
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-05-29 DOI: 10.1103/physrevx.14.021034
Shankar Balasubramanian, Sarang Gopalakrishnan, Alexey Khudorozhkov, Ethan Lake
We introduce a family of local models of dynamics based on “word problems” from computer science and group theory, for which we can place rigorous lower bounds on relaxation timescales. These models can be regarded either as random circuit or local Hamiltonian dynamics and include many familiar examples of constrained dynamics as special cases. The configuration space of these models splits into dynamically disconnected sectors, and for initial states to relax, they must “work out” the other states in the sector to which they belong. When this problem has a high time complexity, relaxation is slow. In some of the cases we study, this problem also has high space complexity. When the space complexity is larger than the system size, an unconventional type of jamming transition can occur, whereby a system of a fixed size is not ergodic but can be made ergodic by appending a large reservoir of sites in a trivial product state. This finding manifests itself in a new type of Hilbert space fragmentation that we call fragile fragmentation. We present explicit examples where slow relaxation and jamming strongly modify the hydrodynamics of conserved densities. In one example, density modulations of wave vector q exhibit almost no relaxation until times O(exp(1/q)), at which point they abruptly collapse. We also comment on extensions of our results to higher dimensions.
我们以计算机科学和群论中的 "文字问题 "为基础,介绍了一系列局部动力学模型,我们可以为这些模型设定严格的松弛时间尺度下限。这些模型既可视为随机电路模型,也可视为局部哈密顿动力学模型,还包括许多我们熟悉的约束动力学特例。这些模型的构型空间分裂成动态断开的扇区,初始态要弛豫,就必须 "解决 "其所属扇区中的其他态。当这个问题的时间复杂度很高时,弛豫的速度就会很慢。在我们研究的一些案例中,这个问题的空间复杂度也很高。当空间复杂度大于系统大小时,就会出现一种非常规的干扰转换,即一个固定大小的系统不是遍历的,但可以通过在琐积状态中添加大量的位点库来使其成为遍历的。这一发现表现为一种新型的希尔伯特空间碎片化,我们称之为脆弱碎片化。我们举例说明了缓慢松弛和干扰会强烈改变守恒密度的流体力学。在其中一个例子中,波矢量 q 的密度调制几乎没有松弛,直到 O(exp(1/q))倍,此时它们突然坍缩。我们还评论了将我们的结果扩展到更高维度的问题。
{"title":"Glassy Word Problems: Ultraslow Relaxation, Hilbert Space Jamming, and Computational Complexity","authors":"Shankar Balasubramanian, Sarang Gopalakrishnan, Alexey Khudorozhkov, Ethan Lake","doi":"10.1103/physrevx.14.021034","DOIUrl":"https://doi.org/10.1103/physrevx.14.021034","url":null,"abstract":"We introduce a family of local models of dynamics based on “word problems” from computer science and group theory, for which we can place rigorous lower bounds on relaxation timescales. These models can be regarded either as random circuit or local Hamiltonian dynamics and include many familiar examples of constrained dynamics as special cases. The configuration space of these models splits into dynamically disconnected sectors, and for initial states to relax, they must “work out” the other states in the sector to which they belong. When this problem has a high time complexity, relaxation is slow. In some of the cases we study, this problem also has high space complexity. When the space complexity is larger than the system size, an unconventional type of jamming transition can occur, whereby a system of a fixed size is not ergodic but can be made ergodic by appending a large reservoir of sites in a trivial product state. This finding manifests itself in a new type of Hilbert space fragmentation that we call fragile fragmentation. We present explicit examples where slow relaxation and jamming strongly modify the hydrodynamics of conserved densities. In one example, density modulations of wave vector <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>q</mi></math> exhibit almost no relaxation until times <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>O</mi><mo mathvariant=\"bold\" stretchy=\"false\">(</mo><mi>exp</mi><mo stretchy=\"false\">(</mo><mn>1</mn><mo>/</mo><mi>q</mi><mo stretchy=\"false\">)</mo><mo mathvariant=\"bold\" stretchy=\"false\">)</mo></mrow></math>, at which point they abruptly collapse. We also comment on extensions of our results to higher dimensions.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141177473","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}
引用次数: 0
Surface Magnetization in Antiferromagnets: Classification, Example Materials, and Relation to Magnetoelectric Responses 反铁磁体的表面磁化:分类、示例材料以及与磁电反应的关系
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-05-28 DOI: 10.1103/physrevx.14.021033
Sophie F. Weber, Andrea Urru, Sayantika Bhowal, Claude Ederer, Nicola A. Spaldin
We use symmetry analysis and density-functional theory to determine and characterize surface terminations that have a finite equilibrium magnetization density in antiferromagnetic materials. A nonzero magnetic dipole moment per unit area or “surface magnetization” can arise on particular surfaces of many antiferromagnets due to the bulk magnetic symmetries. Such surface magnetization underlies intriguing physical phenomena like interfacial magnetic coupling and can be used as a readout method of antiferromagnetic domains. However, a universal description of antiferromagnetic surface magnetization is lacking. We first introduce a classification system based on whether the surface magnetization is either sensitive or robust to roughness and on whether the magnetic dipoles at surface of interest are compensated or uncompensated when the bulk magnetic order is retained at the surface. We show that roughness-sensitive categories can be identified by a simple extension of a previously established group-theory formalism for identifying roughness-robust surface magnetization. We then map the group-theory method of identifying surface magnetization to a novel description in terms of bulk magnetic multipoles, which are already established as symmetry indicators for bulk magnetoelectric responses at both linear and higher orders. We use density-functional calculations to illustrate that nominally compensated surfaces in magnetoelectric Cr2O3 and centrosymmetric altermagnetic FeF2 develop a finite magnetization density at the surface, in agreement with our predictions based on both group theory and the ordering of the bulk multipoles. Our analysis provides a comprehensive basis for understanding the surface magnetic properties and their intimate correspondence to bulk magnetoelectric effects in antiferromagnets and has important implications for technologically relevant phenomena such as exchange-bias coupling.
我们利用对称性分析和密度泛函理论来确定和描述反铁磁材料中具有有限平衡磁化密度的表面终端。由于体磁对称性,许多反铁磁体的特定表面会出现单位面积非零磁偶极矩或 "表面磁化"。这种表面磁化是界面磁耦合等有趣物理现象的基础,可用作反铁磁域的读出方法。然而,目前还缺乏对反铁磁性表面磁化的通用描述。我们首先介绍了一种分类系统,它基于表面磁化对粗糙度是敏感还是稳健,以及在表面保留体磁序时,相关表面的磁偶极子是得到补偿还是未得到补偿。我们的研究表明,粗糙度敏感类别可以通过对之前建立的群论形式主义的简单扩展来识别粗糙度稳健表面磁化。然后,我们将识别表面磁化的群论方法映射到用体磁多极子进行的新描述中,而体磁多极子已被确立为线性和高阶体磁电响应的对称指标。我们使用密度函数计算来说明,磁电 Cr2O3 和中心对称变磁 FeF2 中的名义补偿表面会在表面形成有限的磁化密度,这与我们基于群论和体磁性多极子排序的预测一致。我们的分析为理解反铁磁体的表面磁特性及其与块体磁电效应的密切对应关系提供了全面的基础,并对交换偏置耦合等技术相关现象具有重要意义。
{"title":"Surface Magnetization in Antiferromagnets: Classification, Example Materials, and Relation to Magnetoelectric Responses","authors":"Sophie F. Weber, Andrea Urru, Sayantika Bhowal, Claude Ederer, Nicola A. Spaldin","doi":"10.1103/physrevx.14.021033","DOIUrl":"https://doi.org/10.1103/physrevx.14.021033","url":null,"abstract":"We use symmetry analysis and density-functional theory to determine and characterize surface terminations that have a finite equilibrium magnetization density in antiferromagnetic materials. A nonzero magnetic dipole moment per unit area or “surface magnetization” can arise on particular surfaces of many antiferromagnets due to the bulk magnetic symmetries. Such surface magnetization underlies intriguing physical phenomena like interfacial magnetic coupling and can be used as a readout method of antiferromagnetic domains. However, a universal description of antiferromagnetic surface magnetization is lacking. We first introduce a classification system based on whether the surface magnetization is either sensitive or robust to roughness and on whether the magnetic dipoles at surface of interest are compensated or uncompensated when the bulk magnetic order is retained at the surface. We show that roughness-sensitive categories can be identified by a simple extension of a previously established group-theory formalism for identifying roughness-robust surface magnetization. We then map the group-theory method of identifying surface magnetization to a novel description in terms of bulk magnetic multipoles, which are already established as symmetry indicators for bulk magnetoelectric responses at both linear and higher orders. We use density-functional calculations to illustrate that nominally compensated surfaces in magnetoelectric <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mi>Cr</mi></mrow><mn>2</mn></msub><msub><mrow><mi mathvariant=\"normal\">O</mi></mrow><mn>3</mn></msub></mrow></math> and centrosymmetric altermagnetic <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mi>FeF</mi></mrow><mn>2</mn></msub></mrow></math> develop a finite magnetization density at the surface, in agreement with our predictions based on both group theory and the ordering of the bulk multipoles. Our analysis provides a comprehensive basis for understanding the surface magnetic properties and their intimate correspondence to bulk magnetoelectric effects in antiferromagnets and has important implications for technologically relevant phenomena such as exchange-bias coupling.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141159474","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}
引用次数: 0
Universal Symmetry of Optimal Control at the Microscale 微尺度优化控制的普遍对称性
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-05-24 DOI: 10.1103/physrevx.14.021032
Sarah A. M. Loos, Samuel Monter, Felix Ginot, Clemens Bechinger
Optimizing the energy efficiency of driving processes provides valuable insights into the underlying physics and is of crucial importance for numerous applications, from biological processes to the design of machines and robots. Knowledge of optimal driving protocols is particularly valuable at the microscale, where energy supply is often limited. Here, we experimentally and theoretically investigate the paradigmatic optimization problem of moving a potential carrying a load through a fluid, in a finite time and over a given distance, in such a way that the required work is minimized. An important step towards more realistic systems is the consideration of memory effects in the surrounding fluid, which are ubiquitous in real-world applications. Therefore, our experiments were performed in viscous and viscoelastic media, which are typical environments for synthetic and biological processes on the microscale. Despite marked differences between the protocols in both fluids, we find that the optimal control protocol and the corresponding average particle trajectory always obey a time-reversal symmetry. We show that this symmetry, which surprisingly applies here to a class of processes far from thermal equilibrium, holds universally for various systems, including active, granular, and long-range correlated media in their linear regimes. The uncovered symmetry provides a rigorous and versatile criterion for optimal control that greatly facilitates the search for energy-efficient transport strategies in a wide range of systems. Using a machine learning algorithm, we demonstrate that the algorithmic exploitation of time-reversal symmetry can significantly enhance the performance of numerical optimization algorithms.
优化驱动过程的能效可以提供对基础物理学的宝贵见解,对于从生物过程到机器和机器人设计等众多应用都至关重要。在能量供应往往有限的微观尺度上,最优驱动协议的知识尤其宝贵。在这里,我们通过实验和理论研究了一个典型的优化问题,即在有限的时间内,在给定的距离内,通过流体移动一个携带负载的势能,使所需的功最小化。考虑周围流体中的记忆效应是实现更逼真系统的重要一步,而记忆效应在实际应用中无处不在。因此,我们的实验在粘性和粘弹性介质中进行,这些介质是微尺度合成和生物过程的典型环境。尽管两种流体中的控制协议存在明显差异,但我们发现最优控制协议和相应的粒子平均轨迹始终服从时间反转对称性。我们表明,这种对称性出人意料地适用于一类远离热平衡的过程,它普遍适用于各种系统,包括线性状态下的活动介质、颗粒介质和长程相关介质。未发现的对称性为优化控制提供了一个严格而通用的标准,极大地促进了在各种系统中寻找节能传输策略的工作。我们利用机器学习算法证明,在算法上利用时间反转对称性可以显著提高数值优化算法的性能。
{"title":"Universal Symmetry of Optimal Control at the Microscale","authors":"Sarah A. M. Loos, Samuel Monter, Felix Ginot, Clemens Bechinger","doi":"10.1103/physrevx.14.021032","DOIUrl":"https://doi.org/10.1103/physrevx.14.021032","url":null,"abstract":"Optimizing the energy efficiency of driving processes provides valuable insights into the underlying physics and is of crucial importance for numerous applications, from biological processes to the design of machines and robots. Knowledge of optimal driving protocols is particularly valuable at the microscale, where energy supply is often limited. Here, we experimentally and theoretically investigate the paradigmatic optimization problem of moving a potential carrying a load through a fluid, in a finite time and over a given distance, in such a way that the required work is minimized. An important step towards more realistic systems is the consideration of memory effects in the surrounding fluid, which are ubiquitous in real-world applications. Therefore, our experiments were performed in viscous and viscoelastic media, which are typical environments for synthetic and biological processes on the microscale. Despite marked differences between the protocols in both fluids, we find that the optimal control protocol and the corresponding average particle trajectory always obey a time-reversal symmetry. We show that this symmetry, which surprisingly applies here to a class of processes far from thermal equilibrium, holds universally for various systems, including active, granular, and long-range correlated media in their linear regimes. The uncovered symmetry provides a rigorous and versatile criterion for optimal control that greatly facilitates the search for energy-efficient transport strategies in a wide range of systems. Using a machine learning algorithm, we demonstrate that the algorithmic exploitation of time-reversal symmetry can significantly enhance the performance of numerical optimization algorithms.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141091786","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}
引用次数: 0
Twist-Induced Hyperbolic Shear Metasurfaces 扭曲诱导的双曲剪切元曲面
IF 12.5 1区 物理与天体物理 Q1 Physics and Astronomy Pub Date : 2024-05-24 DOI: 10.1103/physrevx.14.021031
Simon Yves, Emanuele Galiffi, Xiang Ni, Enrico M. Renzi, Andrea Alù
Following the discovery of moiré-driven superconductivity and density waves in twisted-graphene multilayers, twistronics has spurred a surge of interest in tailored broken symmetries through angular rotations enabling new properties, from electronics to photonics and phononics. Analogously, in monoclinic polar crystals a nontrivial angle between nondegenerate dipolar phonon resonances can naturally emerge due to asymmetries in their crystal lattice, and its variations are associated with intriguing polaritonic phenomena, including axial dispersion, i.e., the rotation of the optical axis with frequency, and microscopic shear effects that result in an asymmetric distribution of material loss. So far, these phenomena have been restricted to specific midinfrared frequencies difficult to access with conventional laser sources and fundamentally limited by the degree of asymmetry and by the strength of light-matter interactions available in natural crystals. Here, we leverage the twistronics concept to demonstrate maximal axial dispersion and loss redistribution of hyperbolic waves in elastic metasurfaces, achieved by tailoring the angle between coupled metasurface pairs featuring tailored anisotropy. We show extreme control over elastic wave dispersion and absorption via the twist angle and leverage the resulting phenomena to demonstrate enhanced propagation distance, in-plane reflection-free negative refraction and diffraction-free defect detection. Our work welds the concepts of twistronics, non-Hermiticity, and extreme anisotropy, demonstrating the powerful opportunities enabled by metasurfaces for tunable, highly directional surface-acoustic-wave propagation of great interest for a wide range of applications spanning from seismic mitigation to on-chip phononics and wireless communication systems, hence paving the way toward their translation into emerging photonic and polaritonic metasurface technologies.
继在扭曲石墨烯多层板中发现摩尔纹驱动的超导性和密度波之后,扭曲电子学激起了人们对通过角度旋转实现新特性的定制破缺对称性的浓厚兴趣,包括电子学、光子学和声子学。与此类似,在单斜极性晶体中,由于其晶格的不对称,非孤立二极性声子共振之间会自然出现一个非小角度,其变化与引人入胜的极子现象有关,包括轴向色散(即光轴随频率旋转)和微观剪切效应(导致材料损耗的不对称分布)。迄今为止,这些现象仅限于特定的中红外频率,传统激光源很难进入,而且从根本上受到非对称程度和天然晶体中光-物质相互作用强度的限制。在这里,我们利用双曲概念展示了弹性元表面中双曲波的最大轴向色散和损耗再分布,这是通过调整具有定制各向异性的耦合元表面对之间的角度实现的。我们展示了通过扭转角度对弹性波色散和吸收的极端控制,并利用由此产生的现象展示了增强的传播距离、面内无反射负折射和无衍射缺陷检测。我们的工作融合了扭曲、非恒定性和极端各向异性的概念,展示了超表面为可调、高方向性表面声波传播带来的强大机遇,这些传播对于从地震缓解到片上声学和无线通信系统等广泛应用具有重大意义,从而为将其转化为新兴的光子和极子超表面技术铺平了道路。
{"title":"Twist-Induced Hyperbolic Shear Metasurfaces","authors":"Simon Yves, Emanuele Galiffi, Xiang Ni, Enrico M. Renzi, Andrea Alù","doi":"10.1103/physrevx.14.021031","DOIUrl":"https://doi.org/10.1103/physrevx.14.021031","url":null,"abstract":"Following the discovery of moiré-driven superconductivity and density waves in twisted-graphene multilayers, twistronics has spurred a surge of interest in tailored broken symmetries through angular rotations enabling new properties, from electronics to photonics and phononics. Analogously, in monoclinic polar crystals a nontrivial angle between nondegenerate dipolar phonon resonances can naturally emerge due to asymmetries in their crystal lattice, and its variations are associated with intriguing polaritonic phenomena, including axial dispersion, i.e., the rotation of the optical axis with frequency, and microscopic shear effects that result in an asymmetric distribution of material loss. So far, these phenomena have been restricted to specific midinfrared frequencies difficult to access with conventional laser sources and fundamentally limited by the degree of asymmetry and by the strength of light-matter interactions available in natural crystals. Here, we leverage the twistronics concept to demonstrate maximal axial dispersion and loss redistribution of hyperbolic waves in elastic metasurfaces, achieved by tailoring the angle between coupled metasurface pairs featuring tailored anisotropy. We show extreme control over elastic wave dispersion and absorption via the twist angle and leverage the resulting phenomena to demonstrate enhanced propagation distance, in-plane reflection-free negative refraction and diffraction-free defect detection. Our work welds the concepts of twistronics, non-Hermiticity, and extreme anisotropy, demonstrating the powerful opportunities enabled by metasurfaces for tunable, highly directional surface-acoustic-wave propagation of great interest for a wide range of applications spanning from seismic mitigation to on-chip phononics and wireless communication systems, hence paving the way toward their translation into emerging photonic and polaritonic metasurface technologies.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141091778","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}
引用次数: 0
期刊
Physical Review X
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1