Physical Review X最新文献

{"title":"Topologically Protected Flatness in Chiral Moiré Heterostructures","authors":"Valentin Crépel, Peize Ding, Nishchhal Verma, Nicolas Regnault, Raquel Queiroz","doi":"10.1103/physrevx.15.021056","DOIUrl":"https://doi.org/10.1103/physrevx.15.021056","url":null,"abstract":"The observation of delicate correlated phases in twisted heterostructures of graphene and transition metal dichalcogenides suggests that moiré flat bands are intrinsically resilient against certain types of disorder. Here, we investigate the robustness of moiré flat bands in the chiral limit of the Bistritzer-MacDonald model—applicable to both platforms in certain limits—and demonstrate drastic differences between the first magic angle and higher magic angles in response to chiral symmetric disorder that arise, for instance, from lattice relaxation. We understand these differences using a hidden constant of motion that permits the decomposition of the non-Abelian gauge field induced by interlayer tunnelings into two decoupled Abelian ones. At all magic angles, the resulting effective magnetic field splits into an anomalous contribution and a fluctuating part. The anomalous field maps the moiré flat bands onto a zeroth Dirac Landau level, whose flatness withstands any chiral symmetric perturbation such as nonuniform magnetic fields due to a topological index theorem—thereby underscoring a topological mechanism for band flatness. Only the first magic angle can fully harness this topological protection due to its weak fluctuating magnetic field. In higher magic angles, the amplitude of fluctuations largely exceeds the anomalous contribution, which we find results in a physically meaningless chiral operator and an extremely large sensitivity to microscopic details and an exponential collapse of the single-particle gap. Through numerical simulations, we further study various types of disorder and identify the scattering processes that are enhanced or suppressed in the chiral limit. Interestingly, we find that the topological suppression of disorder broadening persists away from the chiral limit and is further accentuated by isolating a single sublattice polarized flat band in energy. Our analysis suggests the Berry curvature hot spot at the top of the K</a:mi></a:math> and <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:msup><c:mi>K</c:mi><c:mo>′</c:mo></c:msup></c:math> valence band in the transition metal dichalcogenide monolayers is essential for the stability of its moiré flat bands and their correlated states. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"9 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Practical Quantum Advantage on Partially Fault-Tolerant Quantum Computer","authors":"Riki Toshio, Yutaro Akahoshi, Jun Fujisaki, Hirotaka Oshima, Shintaro Sato, Keisuke Fujii","doi":"10.1103/physrevx.15.021057","DOIUrl":"https://doi.org/10.1103/physrevx.15.021057","url":null,"abstract":"Achieving quantum speedups in practical tasks remains challenging for current noisy intermediate-scale quantum (NISQ) devices. These devices always encounter significant obstacles such as inevitable physical errors and the limited scalability of current near-term algorithms. Meanwhile, assuming a typical architecture for fault-tolerant quantum computing (FTQC), realistic applications inevitably require a vast number of qubits, typically exceeding 10&lt;/a:mn&gt;6&lt;/a:mn&gt;&lt;/a:msup&gt;&lt;/a:math&gt;, which seems far beyond near-term realization. In this work, to bridge the gap between the NISQ and FTQC eras, we propose an alternative approach to achieve practical quantum advantages on early-FTQC devices. Our framework is based on partially fault-tolerant logical operations to minimize spatial overhead and avoids the costly distillation techniques typically required for executing non-Clifford gates. To this end, we develop a space-time efficient state preparation protocol to generate an ancillary non-Clifford state consumed for implementing an analog rotation gate with an arbitrary small angle &lt;c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;c:mi&gt;θ&lt;/c:mi&gt;&lt;/c:math&gt; and a remarkably low worst-case error rate below &lt;e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;e:mrow&gt;&lt;e:mi mathvariant=\"script\"&gt;O&lt;/e:mi&gt;&lt;e:mo stretchy=\"false\"&gt;(&lt;/e:mo&gt;&lt;e:mo stretchy=\"false\"&gt;|&lt;/e:mo&gt;&lt;e:mi&gt;θ&lt;/e:mi&gt;&lt;e:mo stretchy=\"false\"&gt;|&lt;/e:mo&gt;&lt;e:msub&gt;&lt;e:mrow&gt;&lt;e:mi&gt;p&lt;/e:mi&gt;&lt;/e:mrow&gt;&lt;e:mrow&gt;&lt;e:mi&gt;ph&lt;/e:mi&gt;&lt;/e:mrow&gt;&lt;/e:msub&gt;&lt;e:mo stretchy=\"false\"&gt;)&lt;/e:mo&gt;&lt;/e:mrow&gt;&lt;/e:math&gt;, where &lt;l:math xmlns:l=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;l:msub&gt;&lt;l:mi&gt;p&lt;/l:mi&gt;&lt;l:mi&gt;ph&lt;/l:mi&gt;&lt;/l:msub&gt;&lt;/l:math&gt; is the physical error rate. Furthermore, we propose several error suppression schemes tailored to our preparation protocol, which are essential to minimize the overhead for mitigating errors. Based on this framework, we present several promising applications that leverage the potential of our framework, including the Trotter simulation and quantum phase estimation (QPE). Notably, we demonstrate that our framework allows us to perform the QPE for an &lt;n:math xmlns:n=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;n:mo stretchy=\"false\"&gt;(&lt;/n:mo&gt;&lt;n:mn&gt;8&lt;/n:mn&gt;&lt;n:mo&gt;×&lt;/n:mo&gt;&lt;n:mn&gt;8&lt;/n:mn&gt;&lt;n:mo stretchy=\"false\"&gt;)&lt;/n:mo&gt;&lt;/n:math&gt;-site Hubbard model with fewer than &lt;r:math xmlns:r=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;r:mn&gt;6.8&lt;/r:mn&gt;&lt;r:mo&gt;×&lt;/r:mo&gt;&lt;r:msup&gt;&lt;r:mn&gt;10&lt;/r:mn&gt;&lt;r:mn&gt;4&lt;/r:mn&gt;&lt;/r:msup&gt;&lt;/r:math&gt; qubits and an execution time of 10.6 days (or 14 min with full parallelization) under &lt;t:math xmlns:t=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;t:msub&gt;&lt;t:mi&gt;p&lt;/t:mi&gt;&lt;t:mi&gt;ph&lt;/t:mi&gt;&lt;/t:msub&gt;&lt;t:mo&gt;=&lt;/t:mo&gt;&lt;t:msup&gt;&lt;t:mn&gt;10&lt;/t:mn&gt;&lt;t:mrow&gt;&lt;t:mo&gt;−&lt;/t:mo&gt;&lt;t:mn&gt;4&lt;/t:mn&gt;&lt;/t:mrow&gt;&lt;/t:msup&gt;&lt;/t:math&gt;, which is significantly faster than recent classical estimation with tensor network techniques (density matrix renormalization group and projected enta","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"10 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Searching for Dark Matter with the Th229 Nuclear Lineshape from Laser Spectroscopy","authors":"Elina Fuchs, Fiona Kirk, Eric Madge, Chaitanya Paranjape, Ekkehard Peik, Gilad Perez, Wolfram Ratzinger, Johannes Tiedau","doi":"10.1103/physrevx.15.021055","DOIUrl":"https://doi.org/10.1103/physrevx.15.021055","url":null,"abstract":"The recent laser excitation of the low-lying Th</a:mi></a:mrow>229</a:mn></a:mmultiscripts></a:mrow></a:math> isomer transition has started a revolution in ultralight dark matter searches. The enhanced sensitivity of this transition to the large class of dark matter models dominantly coupling to quarks and gluons will ultimately allow us to probe coupling strengths 8 orders of magnitude smaller than the current bounds from optical atomic clocks, which are mainly sensitive to dark matter couplings to electrons and photons. We argue that, with increasing precision, observations of the <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mmultiscripts><c:mrow><c:mi>Th</c:mi></c:mrow><c:mprescripts/><c:none/><c:mn>229</c:mn></c:mmultiscripts></c:mrow></c:math> excitation spectrum will soon give the world-leading constraints. Using data from the pioneering laser excitation of <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mmultiscripts><e:mrow><e:mi>Th</e:mi></e:mrow><e:mprescripts/><e:none/><e:mn>229</e:mn></e:mmultiscripts></e:mrow></e:math> by Tiedau [], we present a first dark matter search in the excitation spectrum. While the exclusion limits of our detailed study of the lineshape are still below the sensitivity of currently operating clock experiments, we project the measurement of Zhang [] to surpass it. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"29 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Directional Pumping of Coherent Phonons and Quasiparticle Renormalization in a Dirac Nodal-Line Semimetal","authors":"Chenyu Wang, Daqiang Chen, Yaxian Wang, Sheng Meng","doi":"10.1103/physrevx.15.021053","DOIUrl":"https://doi.org/10.1103/physrevx.15.021053","url":null,"abstract":"Identifying efficient pathways to modulate quantum coherence is a crucial step toward realizing ultrafast switching of macroscopic orders, which requires the microscopical understanding of the interplay between multidegrees of freedom. Here, we demonstrate an all-optical method to control the coherent electron and lattice excitation in a prototypical nodal-line semimetal ZrSiS. We show the displacive excitation of two coherent Raman-active phonon modes, which results in a mode-selective renormalization of its topological band structure comparable with previous experimental observations. We subsequently realize an effective manipulation of the coherent lattice vibration, not only for their amplitude, but also a π</a:mi></a:math>-phase shift by tuning the laser intensity and frequency. We pinpoint that such a phase shift originates from the photoinduced carrier redistribution and can, in turn, determine the quasiparticle renormalization, for example, to induce an ultrafast topological Lifshitz transition, which we anticipate can be detected by pump-probe transport measurements. These results address the requirements for a directional pumping of coherent phonons with laser fields and provide the opportunity to explore exotic nonequilibrium physics. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"42 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143980004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topological Flat-Band-Driven Metallic Thermoelectricity","authors":"Fabian Garmroudi, Jennifer Coulter, Illia Serhiienko, Simone Di Cataldo, Michael Parzer, Alexander Riss, Matthias Grasser, Simon Stockinger, Sergii Khmelevskyi, Kacper Pryga, Bartlomiej Wiendlocha, Karsten Held, Takao Mori, Ernst Bauer, Antoine Georges, Andrej Pustogow","doi":"10.1103/physrevx.15.021054","DOIUrl":"https://doi.org/10.1103/physrevx.15.021054","url":null,"abstract":"Materials where flattened electronic dispersions arise from destructive phase interference, rather than localized orbitals, have emerged as promising platforms for studying emergent quantum phenomena. Crucial next steps involve tuning such flat bands to the Fermi level, where they can be studied at low energy scales, and assessing their potential for practical applications. Here, we show that the interplay of highly dispersive and ultraflat bands inherent to these systems can lead to extreme interband scattering-induced electron-hole asymmetry, which can be harnessed in thermoelectrics. Our comprehensive theoretical and experimental investigation of Ni</a:mi>3</a:mn></a:msub>In</a:mi>1</a:mn>−</a:mo>x</a:mi></a:mrow></a:msub>Sn</a:mi>x</a:mi></a:msub></a:math> kagome metals supports this concept, showing that it could lead to thermoelectric performance on par with state-of-the-art semiconductors such as <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:msub><c:mi>Bi</c:mi><c:mn>2</c:mn></c:msub><c:msub><c:mi>Te</c:mi><c:mn>3</c:mn></c:msub></c:math>. In <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:msub><e:mi>Ni</e:mi><e:mn>3</e:mn></e:msub><e:mi>In</e:mi></e:math>, scattering-induced electron-hole asymmetry is, however, subdued by an exotic conduction mechanism arising from quantum tunneling of charge carriers between Dirac bands, unrelated to the flat band itself. We outline strategies to selectively switch off this tunneling transport through negative chemical pressure or strain. Our study proposes a new direction to explore in topological flat-band systems and vice versa introduces a novel tuning knob for thermoelectric materials. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"49 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143979908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RL Perceptron: Generalization Dynamics of Policy Learning in High Dimensions","authors":"Nishil Patel, Sebastian Lee, Stefano Sarao Mannelli, Sebastian Goldt, Andrew Saxe","doi":"10.1103/physrevx.15.021051","DOIUrl":"https://doi.org/10.1103/physrevx.15.021051","url":null,"abstract":"Reinforcement learning (RL) algorithms have transformed many domains of machine learning. To tackle real-world problems, RL often relies on neural networks to learn policies directly from pixels or other high-dimensional sensory input. By contrast, many theories of RL have focused on discrete state spaces or worst-case analysis, and fundamental questions remain about the dynamics of policy learning in high-dimensional settings. Here, we propose a solvable high-dimensional RL model that can capture a variety of learning protocols, and we derive its typical policy learning dynamics as a set of closed-form ordinary differential equations. We obtain optimal schedules for the learning rates and task difficulty—analogous to annealing schemes and curricula during training in RL—and show that the model exhibits rich behavior, including delayed learning under sparse rewards, a variety of learning regimes depending on reward baselines, and a speed-accuracy trade-off driven by reward stringency. Experiments on variants of the Procgen game “Bossfight” and Arcade Learning Environment game “Pong” also show such a speed-accuracy trade-off in practice. Together, these results take a step toward closing the gap between theory and practice in high-dimensional RL. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"96 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143946225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Power of Random Quantum Circuits in Arbitrary Geometries","authors":"M. DeCross, R. Haghshenas, M. Liu, E. Rinaldi, J. Gray, Y. Alexeev, C. H. Baldwin, J. P. Bartolotta, M. Bohn, E. Chertkov, J. Cline, J. Colina, D. DelVento, J. M. Dreiling, C. Foltz, J. P. Gaebler, T. M. Gatterman, C. N. Gilbreth, J. Giles, D. Gresh, A. Hall, A. Hankin, A. Hansen, N. Hewitt, I. Hoffman, C. Holliman, R. B. Hutson, T. Jacobs, J. Johansen, P. J. Lee, E. Lehman, D. Lucchetti, D. Lykov, I. S. Madjarov, B. Mathewson, K. Mayer, M. Mills, P. Niroula, J. M. Pino, C. Roman, M. Schecter, P. E. Siegfried, B. G. Tiemann, C. Volin, J. Walker, R. Shaydulin, M. Pistoia, S. A. Moses, D. Hayes, B. Neyenhuis, R. P. Stutz, M. Foss-Feig","doi":"10.1103/physrevx.15.021052","DOIUrl":"https://doi.org/10.1103/physrevx.15.021052","url":null,"abstract":"Empirical evidence for a gap between the computational powers of classical and quantum computers has been provided by experiments that sample the output distributions of two-dimensional quantum circuits. Many attempts to close this gap have utilized classical simulations based on tensor network techniques, and their limitations shed light on the improvements to quantum hardware required to frustrate classical simulability. In particular, quantum computers having in excess of approximately 50 qubits are primarily vulnerable to classical simulation due to restrictions on their gate fidelity and their connectivity, the latter determining how many gates are required (and, therefore, how much infidelity is suffered) in generating highly entangled states. Here, we describe recent hardware upgrades to Quantinuum’s H2 quantum computer, enabling it to operate on up to 56 qubits with arbitrary connectivity and 99.843(5)% two-qubit gate fidelity. We define a class of circuits with random geometries that become hard to classically simulate in very low depth and implement them utilizing the flexible connectivity of H2. A careful analysis demonstrating the fast saturation of classical simulation complexity with depth indicates that H2 can yield data well beyond the reach of state-of-the art classical simulation methods at unprecedented fidelities. We find that the considerable difficulty of classically simulating H2 is likely limited only by qubit number, demonstrating the promise and scalability of the quantum charge-coupled device architecture as continued progress is made toward building larger machines. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"4 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143946219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamics of Active Matter: Tracking Dissipation across Scales","authors":"Robin Bebon, Joshua F. Robinson, Thomas Speck","doi":"10.1103/physrevx.15.021050","DOIUrl":"https://doi.org/10.1103/physrevx.15.021050","url":null,"abstract":"The concept of entropy has been pivotal in the formulation of thermodynamics. For systems driven away from thermal equilibrium, a comparable role is played by entropy production and dissipation. Here, we provide a comprehensive picture of how local dissipation due to effective chemical events manifests on large scales in active matter. We start from a microscopic model for a single catalytic particle involving explicit solute molecules and show that it undergoes directed motion. Leveraging stochastic thermodynamics, we calculate the average entropy production rate for interacting particles. We then show how the model of active Brownian particles emerges in a certain limit, and we determine the entropy production rate on the level of the hydrodynamic equations. Our results augment the model of active Brownian particles with rigorous expressions for the dissipation that cannot be inferred from their equations of motion, and we illustrate consequences for wall aggregation and motility-induced phase separation. Notably, our bottom-up approach agrees with the “naive” result from Onsager’s principle for the local dissipation rate. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"29 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143940285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond-Hubbard Pairing in a Cuprate Ladder","authors":"Hari Padma, Jinu Thomas, Sophia F. R. TenHuisen, Wei He, Ziqiang Guan, Jiemin Li, Byungjune Lee, Yu Wang, Seng Huat Lee, Zhiqiang Mao, Hoyoung Jang, Valentina Bisogni, Jonathan Pelliciari, Mark P. M. Dean, Steven Johnston, Matteo Mitrano","doi":"10.1103/physrevx.15.021049","DOIUrl":"https://doi.org/10.1103/physrevx.15.021049","url":null,"abstract":"The Hubbard model is believed to capture the essential physics of cuprate superconductors. However, recent theoretical studies suggest that it fails to reproduce a robust and homogeneous superconducting ground state. Here, using resonant inelastic x-ray scattering and density matrix renormalization group calculations, we show that magnetic excitations in the prototypical cuprate ladder Sr</a:mi></a:mrow>14</a:mn></a:mrow></a:msub>Cu</a:mi></a:mrow>24</a:mn></a:mrow></a:msub>O</a:mi></a:mrow>41</a:mn></a:mrow></a:msub></a:mrow></a:math> are inconsistent with those of a simple Hubbard model. The magnetic response of hole carriers, contributing to an emergent branch of spin-flip excitations, is strongly suppressed. This effect is the consequence of strong <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><d:mi>d</d:mi></d:math>-wavelike pairing, enhanced by nearly an order of magnitude through a large nearest-neighbor attractive interaction and persisting up to at least 260 K. The close connection between the physics of cuprate ladders and that of the two-dimensional compounds suggests that such an enhanced hole pairing may be a universal feature of superconducting cuprates. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"1 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143940286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superconductivity in the Parent Infinite-Layer Nickelate NdNiO2","authors":"C. T. Parzyck, Y. Wu, L. Bhatt, M. Kang, Z. Arthur, T. M. Pedersen, R. Sutarto, S. Fan, J. Pelliciari, V. Bisogni, G. Herranz, A. B. Georgescu, D. G. Hawthorn, L. F. Kourkoutis, D. A. Muller, D. G. Schlom, K. M. Shen","doi":"10.1103/physrevx.15.021048","DOIUrl":"https://doi.org/10.1103/physrevx.15.021048","url":null,"abstract":"We report evidence for superconductivity with onset temperatures up to 11 K in thin films of the infinite-layer nickelate parent compound NdNiO</a:mi></a:mrow>2</a:mn></a:mrow></a:msub></a:mrow></a:math>. A combination of oxide molecular beam epitaxy and atomic hydrogen reduction yields samples with high crystallinity and low residual resistivities, a substantial fraction of which exhibit superconducting transitions. We survey a large series of samples with a variety of techniques, including electrical transport, scanning transmission electron microscopy, x-ray absorption spectroscopy, and resonant inelastic x-ray scattering, to investigate the possible origins of superconductivity. We propose that superconductivity could be intrinsic to the undoped infinite-layer nickelates but suppressed by disorder due to a possibly sign-changing order parameter, a finding which would necessitate a reconsideration of the nickelate phase diagram. Another possible hypothesis is that the parent materials can be hole doped from randomly dispersed apical oxygen atoms, which would suggest an alternative pathway for achieving superconductivity. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"55 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143940287","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}