Physical Review X最新文献

{"title":"A Quantum Critical Line Bounds the High Field Metamagnetic Transition Surface in UTe2","authors":"Z. Wu, T. I. Weinberger, A. J. Hickey, D. V. Chichinadze, D. Shaffer, A. Cabala, H. Chen, M. Long, T. J. Brumm, W. Xie, Y. Ling, Z. Zhu, Y. Skourski, D. E. Graf, V. Sechovský, M. Vališka, G. G. Lonzarich, F. M. Grosche, A. G. Eaton","doi":"10.1103/physrevx.15.021019","DOIUrl":"https://doi.org/10.1103/physrevx.15.021019","url":null,"abstract":"Quantum critical phenomena are widely studied across various materials families, from high-temperature superconductors to magnetic insulators. They occur when a thermodynamic phase transition is suppressed to zero temperature as a function of some tuning parameter such as pressure or magnetic field. This generally yields a point of instability—a so-called quantum critical point—at which the phase transition is driven exclusively by quantum fluctuations. Here, we show that the heavy fermion metamagnet UTe</a:mi></a:mrow>2</a:mn></a:mrow></a:msub></a:mrow></a:math> possesses a quantum phase transition at extreme magnetic field strengths of over 70 T. Rather than terminating at one singular point, we find that the phase boundary is sensitive to magnetic field components in each of the three Cartesian axes of magnetic field space. This results in the transition surface being bounded by a continuous ring of quantum critical points, the locus of which forms an extended line of quantum criticality—a novel form of quantum critical phase boundary. Within this quantum critical line sits a magnetic field-induced superconducting state in a toroidal shape, which persists to fields over 70 T. We model our data by a phenomenological free energy expansion and show how a quantum critical line—rather than a more conventional singular point of instability—anchors the remarkable high magnetic field phase landscape of <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:msub><c:mrow><c:mi>UTe</c:mi></c:mrow><c:mrow><c:mn>2</c:mn></c:mrow></c:msub></c:mrow></c:math>. <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":"25 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846556","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":"Electronic Nematicity in Interface Superconducting LAO/KTO(111)","authors":"X. B. Cheng, M. Zhang, Y. Q. Sun, G. F. Chen, M. Qin, T. S. Ren, X. S. Cao, Y. W. Xie, J. Wu","doi":"10.1103/physrevx.15.021018","DOIUrl":"https://doi.org/10.1103/physrevx.15.021018","url":null,"abstract":"The symmetry of superconducting and normal states is at the core of superconductivity research. Emergent electronic nematicity, which spontaneously breaks the rotational symmetry, has been found in the normal state of various types of unconventional superconductors. Here, we exploit the angle-resolved resistivity method to systematically measure the nematicity of the interface superconducting LaAlO</a:mi></a:mrow>3</a:mn></a:msub>/</a:mo>KTaO</a:mi></a:mrow>3</a:mn></a:msub>(</a:mo>111</a:mn>)</a:mo></a:mrow></a:math> (<e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mi>LAO</e:mi><e:mo>/</e:mo><e:mi>KTO</e:mi></e:mrow></e:math>). Compared to the normal state, electronic nematicity is enhanced substantially by superconducting fluctuations around the superconducting temperature <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mrow><g:msub><g:mi>T</g:mi><g:mi mathvariant=\"normal\">c</g:mi></g:msub></g:mrow></g:math>. More importantly, <j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><j:mrow><j:msub><j:mi>T</j:mi><j:mi mathvariant=\"normal\">c</j:mi></j:msub></j:mrow></j:math> is also anisotropic in plane and angle dependent. The nematicity consists of a dominant <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:mrow><m:msub><m:mi mathvariant=\"normal\">C</m:mi><m:mn>2</m:mn></m:msub></m:mrow></m:math> component and a <p:math xmlns:p=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><p:mrow><p:msub><p:mi mathvariant=\"normal\">C</p:mi><p:mn>4</p:mn></p:msub></p:mrow></p:math> component, which can be explained by the presence of nematic domains. After the superconductivity is suppressed by a magnetic field, the uncovered quantum metal state manifests significant nematicity that is contributed by residual nematic superconducting fluctuations. A coherent picture of nematic interface superconductivity can be retrieved from the measured nematicity phase diagram that is crucial for the understanding of quantum metal state, electronic nematicity, and interface 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":"38 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841040","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":"Accuracy Guarantees and Quantum Advantage in Analog Open Quantum Simulation with and without Noise","authors":"Vikram Kashyap, Georgios Styliaris, Sara Mouradian, J. Ignacio Cirac, Rahul Trivedi","doi":"10.1103/physrevx.15.021017","DOIUrl":"https://doi.org/10.1103/physrevx.15.021017","url":null,"abstract":"Many-body open quantum systems, described by Lindbladian master equations, are a rich class of physical models that display complex equilibrium and out-of-equilibrium phenomena which remain to be understood. In this paper, we theoretically analyze noisy analog quantum simulation of geometrically local open quantum systems and provide evidence that this problem both is hard to simulate on classical computers and could be approximately solved on near-term quantum devices. First, given a noiseless quantum simulator, we show that the dynamics of local observables and the fixed-point expectation values of rapidly mixing local observables in geometrically local Lindbladians can be obtained to a precision of ϵ</a:mi></a:math> in time that is <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mi>poly</c:mi></c:mrow><c:mo stretchy=\"false\">(</c:mo><c:msup><c:mi>ϵ</c:mi><c:mrow><c:mo>−</c:mo><c:mn>1</c:mn></c:mrow></c:msup><c:mo stretchy=\"false\">)</c:mo></c:math> and uniform in system size. Furthermore, we establish that the quantum simulator would provide a superpolynomial advantage, in run-time scaling with respect to the target precision and either the evolution time (when simulating dynamics) or the Lindbladian’s decay rate (when simulating fixed points), over any classical algorithm for these problems, assuming <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mrow><g:mi>BQP</g:mi><g:mo stretchy=\"false\">≠</g:mo><g:mi>BPP</g:mi></g:mrow></g:math>. We then consider the presence of noise in the quantum simulator in the form of additional geometrically local Lindbladian terms. We show that the simulation tasks considered in this paper are stable to errors; i.e., they can be solved to a noise-limited, but system-size independent, precision. Finally, we establish that, assuming <j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><j:mrow><j:mi>BQP</j:mi><j:mo stretchy=\"false\">≠</j:mo><j:mi>BPP</j:mi></j:mrow></j:math>, there are stable geometrically local Lindbladian simulation problems such that, as the noise rate on the simulator is reduced, classical algorithms must take time superpolynomially longer in the inverse noise rate to attain the same precision as the analog quantum simulator. <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":"24 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841091","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":"Deep-Learning Generation of High-Resolution Images of Live Cells in Culture Using Tri-Frequency Acoustic Images","authors":"Natsumi Fujiwara, Midori Uno, Hiroki Fukuda, Akira Nagakubo, Shao Ying Tan, Masahiro Kino-oka, Hirotsugu Ogi","doi":"10.1103/physrevx.15.021015","DOIUrl":"https://doi.org/10.1103/physrevx.15.021015","url":null,"abstract":"Ultrasound microscopy is the only technique that has the ability to monitor live-cell morphology over a long period of time without causing any damage to the cells, but its longer wavelength prevents one from obtaining high-resolution cell images. Here, we propose a deep-learning (DL) method for generating high-resolution acoustic images. By preparing datasets consisting of many pairs of acoustic and optical-microscope images for the same cells and training them, a high-resolution image comparable to optical microscopy is generated from an acoustic image. Importantly, the most accurate images are generated when three-layer (RGB) images containing not only high-frequency (approximately 180 MHz) images but also lower-frequency (approximately 100 MHz) images are used as the input images, which is attributed to enhanced acoustic absorption in the nucleus because the nucleus resonates in this low-frequency band. The DL scheme with the tri-frequency image input is applied to human mesenchymal stem cells and human induced pluripotent stem cells, and the high image-generation capability is demonstrated. As a result, high-resolution acoustic microscopy images are obtained for the same cells for over 24 h, without the typical cell damage encountered using optical imaging. <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":"50 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836871","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":"Topology of Discrete Quantum Feedback Control","authors":"Masaya Nakagawa, Masahito Ueda","doi":"10.1103/physrevx.15.021016","DOIUrl":"https://doi.org/10.1103/physrevx.15.021016","url":null,"abstract":"A general framework for analyzing the topology of quantum channels of single-particle systems is developed to find a class of genuinely dynamical topological phases that can be realized by means of discrete quantum feedback control. We provide a symmetry classification of quantum channels by identifying ten symmetry classes of discrete quantum feedback control with projective measurements. We construct various types of topological feedback control by using topological Maxwell demons that achieve robust feedback-controlled chiral or helical transport against noise and decoherence. Topological feedback control thus offers a versatile tool for creating and controlling nonequilibrium topological phases in open quantum systems that are distinct from non-Hermitian and Lindbladian systems and should provide a guiding principle for topology-based design of quantum feedback control. <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":"2 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836965","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":"From Existing and New Nuclear and Astrophysical Constraints to Stringent Limits on the Equation of State of Neutron-Rich Dense Matter","authors":"Hauke Koehn, Henrik Rose, Peter T. H. Pang, Rahul Somasundaram, Brendan T. Reed, Ingo Tews, Adrian Abac, Oleg Komoltsev, Nina Kunert, Aleksi Kurkela, Michael W. Coughlin, Brian F. Healy, Tim Dietrich","doi":"10.1103/physrevx.15.021014","DOIUrl":"https://doi.org/10.1103/physrevx.15.021014","url":null,"abstract":"Through continuous progress in nuclear theory and experiment and an increasing number of neutron-star (NS) observations, a multitude of information about the equation of state (EOS) for matter at extreme densities is available. To constrain the EOS across its entire density range, this information needs to be combined consistently. However, the impact and model dependency of individual observations vary. Given their growing number, assessing the various methods is crucial to compare the respective effects on the EOS and discover potential biases. For this purpose, we present a broad compendium of different constraints and apply them individually to a large set of EOS candidates within a Bayesian framework. Specifically, we explore different ways of how chiral effective field theory and perturbative quantum chromodynamics can be used to place a likelihood on EOS candidates. We also investigate the impact of nuclear experimental constraints, as well as different radio and x-ray observations of NS masses and radii. This is augmented by reanalyses of the existing data from binary neutron star coalescences, in particular of GW170817, with improved models for the tidal waveform and kilonova light curves, which we also utilize to construct a tight upper limit of 2.39&lt;/a:mn&gt;M&lt;/a:mi&gt;⊙&lt;/a:mo&gt;&lt;/a:msub&gt;&lt;/a:math&gt; on the TOV mass based on GW170817’s remnant. Our diverse set of constraints is eventually combined to obtain stringent limits on NS properties. We organize the combination in a way to distinguish between constraints where the systematic uncertainties are deemed small and those that rely on less conservative assumptions. For the former, we find the radius of the canonical &lt;d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;d:mn&gt;1.4&lt;/d:mn&gt;&lt;d:msub&gt;&lt;d:mi&gt;M&lt;/d:mi&gt;&lt;d:mo stretchy=\"false\"&gt;⊙&lt;/d:mo&gt;&lt;/d:msub&gt;&lt;/d:math&gt; neutron star to be &lt;g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;g:msub&gt;&lt;g:mi&gt;R&lt;/g:mi&gt;&lt;g:mn&gt;1.4&lt;/g:mn&gt;&lt;/g:msub&gt;&lt;g:mo&gt;=&lt;/g:mo&gt;&lt;g:mn&gt;12.2&lt;/g:mn&gt;&lt;g:msubsup&gt;&lt;g:mn&gt;6&lt;/g:mn&gt;&lt;g:mrow&gt;&lt;g:mo&gt;−&lt;/g:mo&gt;&lt;g:mn&gt;0.91&lt;/g:mn&gt;&lt;/g:mrow&gt;&lt;g:mrow&gt;&lt;g:mo&gt;+&lt;/g:mo&gt;&lt;g:mn&gt;0.80&lt;/g:mn&gt;&lt;/g:mrow&gt;&lt;/g:msubsup&gt;&lt;g:mtext&gt; &lt;/g:mtext&gt;&lt;g:mtext&gt; &lt;/g:mtext&gt;&lt;g:mi&gt;km&lt;/g:mi&gt;&lt;/g:math&gt; and the TOV mass at &lt;i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;i:msub&gt;&lt;i:mi&gt;M&lt;/i:mi&gt;&lt;i:mrow&gt;&lt;i:mi&gt;TOV&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;/i:msub&gt;&lt;i:mo&gt;=&lt;/i:mo&gt;&lt;i:mn&gt;2.2&lt;/i:mn&gt;&lt;i:msubsup&gt;&lt;i:mn&gt;5&lt;/i:mn&gt;&lt;i:mrow&gt;&lt;i:mo&gt;−&lt;/i:mo&gt;&lt;i:mn&gt;0.22&lt;/i:mn&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:mo&gt;+&lt;/i:mo&gt;&lt;i:mn&gt;0.42&lt;/i:mn&gt;&lt;/i:mrow&gt;&lt;/i:msubsup&gt;&lt;i:msub&gt;&lt;i:mi&gt;M&lt;/i:mi&gt;&lt;i:mo stretchy=\"false\"&gt;⊙&lt;/i:mo&gt;&lt;/i:msub&gt;&lt;/i:math&gt; (95% credibility). Including all the presented constraints yields &lt;l:math xmlns:l=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;l:msub&gt;&lt;l:mi&gt;R&lt;/l:mi&gt;&lt;l:mn&gt;1.4&lt;/l:mn&gt;&lt;/l:msub&gt;&lt;l:mo&gt;=&lt;/l:mo&gt;&lt;l:mn&gt;12.2&lt;/l:mn&gt;&lt;l:msubsup&gt;&lt;l:mn&gt;0&lt;/l:mn&gt;&lt;l:mrow&gt;&lt;l:mo&gt;−&lt;/l:mo&gt;&lt;l:mn&gt;0.48&lt;/l:mn&gt;&lt;/l:mrow&gt;&lt;l:mrow&gt;&lt;l:mo&gt;+&lt;/l:mo&gt;&lt;l:mn&gt;0.50&lt;/l:mn&gt;&lt;/l:mrow&gt;&lt;/l:msubsup&gt;&lt;l:mtext&gt; &lt;/l:mtext&gt;&lt;l:mtext&gt; &lt;/l:mtext&gt;&lt;l:mi","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"22 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143831860","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":"Classification of Joint Quantum Measurements Based on Entanglement Cost of Localization","authors":"Jef Pauwels, Alejandro Pozas-Kerstjens, Flavio Del Santo, Nicolas Gisin","doi":"10.1103/physrevx.15.021013","DOIUrl":"https://doi.org/10.1103/physrevx.15.021013","url":null,"abstract":"Despite their importance in quantum theory, joint quantum measurements remain poorly understood. An intriguing conceptual and practical question is whether joint quantum measurements on separated systems can be performed without bringing them together. Remarkably, by using shared entanglement, this can be achieved perfectly when disregarding the postmeasurement state. However, existing localization protocols typically require unbounded entanglement. In this work, we address the fundamental question: “Which joint measurements can be localized with a finite amount of entanglement?” We develop finite-resource versions of teleportation-based schemes and analytically classify all two-qubit measurements that can be localized in the first levels of the resulting hierarchies. These levels include several measurements with exceptional properties and symmetries, such as the Bell state measurement and the elegant joint measurement. This leads us to propose a systematic classification of joint measurements based on entanglement cost, which we argue directly connects with the complexity of implementing those measurements. We illustrate how to numerically explore higher levels and construct generalizations to higher dimensions and multipartite settings. <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":"60 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827442","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":"Digital Discovery of Interferometric Gravitational Wave Detectors","authors":"Mario Krenn, Yehonathan Drori, Rana X Adhikari","doi":"10.1103/physrevx.15.021012","DOIUrl":"https://doi.org/10.1103/physrevx.15.021012","url":null,"abstract":"Gravitational waves, detected a century after they were first theorized, are space-time distortions caused by some of the most cataclysmic events in the Universe, including black hole mergers and supernovae. The successful detection of these waves has been made possible by ingenious detectors designed by human experts. Beyond these successful designs, the vast space of experimental configurations remains largely unexplored, offering an exciting territory potentially rich in innovative and unconventional detection strategies. Here, we demonstrate an intelligent computational strategy to explore this enormous space, discovering unorthodox topologies for gravitational wave detectors that significantly outperform the currently best-known designs under realistic experimental constraints. This increases the potentially observable volume of the Universe by up to 50-fold. Moreover, by analyzing the best solutions from our superhuman algorithm, we uncover entirely new physics ideas at their core. At a bigger picture, our methodology can readily be extended to AI-driven design of experiments across wide domains of fundamental physics, opening fascinating new windows into the Universe. <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":"26 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822878","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":"Control of Solid-State Nuclear Spin Qubits Using an Electron Spin- 1/2","authors":"Hans K. C. Beukers, Christopher Waas, Matteo Pasini, Hendrik B. van Ommen, Zarije Ademi, Mariagrazia Iuliano, Nina Codreanu, Julia M. Brevoord, Tim Turan, Tim H. Taminiau, Ronald Hanson","doi":"10.1103/physrevx.15.021011","DOIUrl":"https://doi.org/10.1103/physrevx.15.021011","url":null,"abstract":"Solid-state quantum registers consisting of optically active electron spins with nearby nuclear spins are promising building blocks for future quantum technologies. For electron spin-1 registers, dynamical decoupling (DD) quantum gates have been developed that enable the precise control of multiple nuclear spin qubits. However, for the important class of electron spin-1</a:mn>/</a:mo>2</a:mn></a:mrow></a:math> systems, this control method suffers from intrinsic selectivity limitations, resulting in reduced nuclear spin gate fidelities. Here, we demonstrate improved control of single nuclear spins by an electron spin-<c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mn>1</c:mn><c:mo>/</c:mo><c:mn>2</c:mn></c:mrow></c:math> using dynamically decoupled radio-frequency (DDRF) gates. We make use of the electron spin-<e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mn>1</e:mn><e:mo>/</e:mo><e:mn>2</e:mn></e:mrow></e:math> of a diamond tin-vacancy center, showing high-fidelity single-qubit gates, single-shot readout, and spin coherence beyond a millisecond. The DD control is used as a benchmark to observe and control a single <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mrow><g:mmultiscripts><g:mrow><g:mn>3</g:mn></g:mrow><g:mprescripts/><g:none/><g:mrow><g:mn>1</g:mn></g:mrow></g:mmultiscripts><g:mi mathvariant=\"normal\">C</g:mi></g:mrow></g:math> nuclear spin. Using the DDRF control method, we demonstrate improved control on that spin. In addition, we find and control an additional nuclear spin that is insensitive to the DD control method. Using these DDRF gates, we show entanglement between the electron and the nuclear spin with 72(3)% state fidelity. Our extensive simulations indicate that DDRF gate fidelities well in excess are feasible. Finally, we employ time-resolved photon detection during readout to quantify the hyperfine coupling for the electron’s optically excited state. Our work provides key insights into the challenges and opportunities for nuclear spin control in electron spin-<j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><j:mrow><j:mn>1</j:mn><j:mo>/</j:mo><j:mn>2</j:mn></j:mrow></j:math> systems, opening the door to multiqubit experiments on these promising qubit platforms. <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":"183 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spin-Stripe Order Tied to the Pseudogap Phase in La1.8−xEu0.2SrxCuO4","authors":"Anne Missiaen, Hadrien Mayaffre, Steffen Krämer, Dan Zhao, Yanbing Zhou, Tao Wu, Xianhui Chen, Sunseng Pyon, Tomohiro Takayama, Hidenori Takagi, David LeBoeuf, Marc-Henri Julien","doi":"10.1103/physrevx.15.021010","DOIUrl":"https://doi.org/10.1103/physrevx.15.021010","url":null,"abstract":"Although spin and charge stripes in high-T&lt;/a:mi&gt;c&lt;/a:mi&gt;&lt;/a:msub&gt;&lt;/a:math&gt; cuprates have been extensively studied, the exact range of carrier concentration over which they form a static order remains uncertain, complicating efforts to understand their significance. The problem is challenging due to the combined effects of quenched disorder and competition with superconductivity—both significant in cuprates—which add to the inherent difficulty of determining phase boundaries. In &lt;c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;c:mrow&gt;&lt;c:msub&gt;&lt;c:mrow&gt;&lt;c:mi&gt;La&lt;/c:mi&gt;&lt;/c:mrow&gt;&lt;c:mrow&gt;&lt;c:mn&gt;2&lt;/c:mn&gt;&lt;c:mo&gt;−&lt;/c:mo&gt;&lt;c:mi&gt;x&lt;/c:mi&gt;&lt;/c:mrow&gt;&lt;/c:msub&gt;&lt;c:mrow&gt;&lt;c:msub&gt;&lt;c:mrow&gt;&lt;c:mi&gt;Sr&lt;/c:mi&gt;&lt;/c:mrow&gt;&lt;c:mrow&gt;&lt;c:mi&gt;x&lt;/c:mi&gt;&lt;/c:mrow&gt;&lt;/c:msub&gt;&lt;/c:mrow&gt;&lt;c:mrow&gt;&lt;c:msub&gt;&lt;c:mrow&gt;&lt;c:mi&gt;CuO&lt;/c:mi&gt;&lt;/c:mrow&gt;&lt;c:mrow&gt;&lt;c:mn&gt;4&lt;/c:mn&gt;&lt;/c:mrow&gt;&lt;/c:msub&gt;&lt;/c:mrow&gt;&lt;/c:mrow&gt;&lt;/c:math&gt; (LSCO) and in zero external magnetic field, static spin stripes are confined to a doping range well below &lt;e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;e:msup&gt;&lt;e:mi&gt;p&lt;/e:mi&gt;&lt;e:mo&gt;*&lt;/e:mo&gt;&lt;/e:msup&gt;&lt;/e:math&gt;, the pseudogap boundary at zero temperature. However, when high fields suppress the competing effect of superconductivity, spin-stripe order is found to extend up to &lt;g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;g:msup&gt;&lt;g:mi&gt;p&lt;/g:mi&gt;&lt;g:mo&gt;*&lt;/g:mo&gt;&lt;/g:msup&gt;&lt;/g:math&gt;. Here, we investigate &lt;i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;i:mrow&gt;&lt;i:msub&gt;&lt;i:mrow&gt;&lt;i:mi&gt;La&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:mn&gt;1.8&lt;/i:mn&gt;&lt;i:mo&gt;−&lt;/i:mo&gt;&lt;i:mi&gt;x&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;/i:msub&gt;&lt;i:mrow&gt;&lt;i:msub&gt;&lt;i:mrow&gt;&lt;i:mi&gt;Eu&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:mn&gt;0.2&lt;/i:mn&gt;&lt;/i:mrow&gt;&lt;/i:msub&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:msub&gt;&lt;i:mrow&gt;&lt;i:mi&gt;Sr&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:mi&gt;x&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;/i:msub&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:msub&gt;&lt;i:mrow&gt;&lt;i:mi&gt;CuO&lt;/i:mi&gt;&lt;/i:mrow&gt;&lt;i:mrow&gt;&lt;i:mn&gt;4&lt;/i:mn&gt;&lt;/i:mrow&gt;&lt;/i:msub&gt;&lt;/i:mrow&gt;&lt;/i:mrow&gt;&lt;/i:math&gt; (Eu-LSCO) using &lt;k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;k:mrow&gt;&lt;k:mmultiscripts&gt;&lt;k:mrow&gt;&lt;k:mi&gt;La&lt;/k:mi&gt;&lt;/k:mrow&gt;&lt;k:mprescripts/&gt;&lt;k:none/&gt;&lt;k:mrow&gt;&lt;k:mn&gt;139&lt;/k:mn&gt;&lt;/k:mrow&gt;&lt;/k:mmultiscripts&gt;&lt;/k:mrow&gt;&lt;/k:math&gt; nuclear magnetic resonance and observe field-dependent spin fluctuations suggesting a similar competition between superconductivity and spin order as in LSCO. Nevertheless, we find that static spin stripes are present practically up to &lt;m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;m:msup&gt;&lt;m:mi&gt;p&lt;/m:mi&gt;&lt;m:mo&gt;*&lt;/m:mo&gt;&lt;/m:msup&gt;&lt;/m:math&gt; irrespective of field strength: The stronger stripe order in Eu-LSCO prevents superconductivity from enforcing a nonmagnetic ground state, except very close to &lt;o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;o:msup&gt;&lt;o:mi&gt;p&lt;/o:mi&gt;&lt;o:mo&gt;*&lt;/o:mo&gt;&lt;/o:msup&gt;&lt;/o:math&gt;. Thus, spin-stripe order is consistently bounded by &lt;q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"&gt;&lt;q:msup&gt;&lt;q:mi&gt;p&lt;/q:mi&gt;&lt;q:mo&gt;*&lt;/q:mo&gt;&lt;/q:msup&gt;&lt;/q:math&gt; in both LS","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"108 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143819444","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}