Physical Review X最新文献

{"title":"Thermodynamic Evidence of Fermionic Behavior in the Vicinity of One-Ninth Plateau in a Kagome Antiferromagnet","authors":"Guoxin Zheng, Dechen Zhang, Yuan Zhu, Kuan-Wen Chen, Aaron Chan, Kaila Jenkins, Byungmin Kang, Zhenyuan Zeng, Aini Xu, D. Ratkovski, Joanna Blawat, Alimamy F. Bangura, John Singleton, Patrick A. Lee, Shiliang Li, Lu Li","doi":"10.1103/physrevx.15.021076","DOIUrl":"https://doi.org/10.1103/physrevx.15.021076","url":null,"abstract":"The spin-1</a:mn>/</a:mo>2</a:mn></a:mrow></a:math> kagome Heisenberg antiferromagnets are believed to host exotic quantum entangled states. Recently, the reports of <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>9</c:mn></c:mrow></c:math> magnetization plateau and magnetic oscillations in a kagome antiferromagnet <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mrow><e:msub><e:mrow><e:mi>YCu</e:mi></e:mrow><e:mrow><e:mn>3</e:mn></e:mrow></e:msub></e:mrow><e:msub><e:mrow><e:mo stretchy=\"false\">(</e:mo><e:mrow><e:mi>OH</e:mi></e:mrow><e:mo stretchy=\"false\">)</e:mo></e:mrow><e:mrow><e:mn>6</e:mn></e:mrow></e:msub><e:mrow><e:msub><e:mrow><e:mi>Br</e:mi></e:mrow><e:mrow><e:mn>2</e:mn></e:mrow></e:msub></e:mrow><e:mo stretchy=\"false\">[</e:mo><e:msub><e:mrow><e:mtext>Br</e:mtext></e:mrow><e:mrow><e:mi>x</e:mi></e:mrow></e:msub><e:msub><e:mrow><e:mo stretchy=\"false\">(</e:mo><e:mrow><e:mi>OH</e:mi></e:mrow><e:mo stretchy=\"false\">)</e:mo></e:mrow><e:mrow><e:mn>1</e:mn><e:mo>−</e:mo><e:mi>x</e:mi></e:mrow></e:msub><e:mo stretchy=\"false\">]</e:mo></e:mrow></e:math> (YCOB) have made this material a promising candidate for experimentally realizing quantum spin liquid states. Here, we present measurements of the specific heat <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:msub><m:mi>C</m:mi><m:mi>p</m:mi></m:msub></m:math> in YCOB in high magnetic fields (up to 41.5 T) down to 0.46 K, and the <o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><o:mrow><o:mn>1</o:mn><o:mo>/</o:mo><o:mn>9</o:mn></o:mrow></o:math> plateau feature has been confirmed. Moreover, the temperature dependence of <q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><q:msub><q:mi>C</q:mi><q:mi>p</q:mi></q:msub><q:mo>/</q:mo><q:mi>T</q:mi></q:math> in the vicinity of <s:math xmlns:s=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><s:mrow><s:mn>1</s:mn><s:mo>/</s:mo><s:mn>9</s:mn></s:mrow></s:math> plateau region can be fitted by a linear in <u:math xmlns:u=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><u:mi>T</u:mi></u:math> term which indicates the presence of a Dirac spectrum, together with a constant term, which indicates a finite density of states contributed by other spinon Fermi surfaces. Surprisingly, the constant term is highly anisotropic in the direction of the magnetic field. Additionally, we observe a double-peak feature near 30 T above the <w:math xmlns:w=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><w:mrow><w:mn>1</w:mn><w:mo>/</w:mo><w:mn>9</w:mn></w:mrow></w:math> plateau which is another hallmark of fermionic excitations in the specific heat. This combination of gapless behavior and the double-peak structure strongly suggests that the <y:math xmlns:y=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><y:mrow><y:mn>1</y:mn><y:mo>/</y:mo><y:mn>9</y:mn></y:mrow></y:math> plateau in YCOB is nontri","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"11 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184097","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":"Incommensurate Antiferromagnetism in UTe2 under Pressure","authors":"W. Knafo, T. Thebault, S. Raymond, P. Manuel, D. D. Khalyavin, F. Orlandi, E. Ressouche, K. Beauvois, G. Lapertot, K. Kaneko, D. Aoki, D. Braithwaite, G. Knebel","doi":"10.1103/physrevx.15.021075","DOIUrl":"https://doi.org/10.1103/physrevx.15.021075","url":null,"abstract":"The discovery of multiple superconducting phases in UTe</a:mi></a:mrow>2</a:mn></a:mrow></a:msub></a:mrow></a:math> boosted research on correlated-electron physics. This heavy-fermion paramagnet was rapidly identified as a reference compound to study the interplay between magnetism and unconventional superconductivity with multiple degrees of freedom. The proximity to a ferromagnetic quantum phase transition was initially proposed as a driving force to triplet-pairing superconductivity. However, we find here that long-range incommensurate antiferromagnetic order is established under pressure. The propagation vector <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:msub><c:mi mathvariant=\"bold\">k</c:mi><c:mi mathvariant=\"bold\">m</c:mi></c:msub><c:mo>=</c:mo><c:mo stretchy=\"false\">(</c:mo><c:mn>0.07</c:mn><c:mo>,</c:mo><c:mn>0.33</c:mn><c:mo>,</c:mo><c:mn>1</c:mn><c:mo stretchy=\"false\">)</c:mo></c:math> of the antiferromagnetic phase is close to a wave vector where antiferromagnetic fluctuations have previously been observed at ambient pressure. These elements support that <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><i:mrow><i:msub><i:mrow><i:mi>UTe</i:mi></i:mrow><i:mrow><i:mn>2</i:mn></i:mrow></i:msub></i:mrow></i:math> is a nearly antiferromagnet at ambient pressure. Our work appeals for theories modeling the evolution of the magnetic interactions and electronic properties, driving a correlated paramagnetic regime at ambient pressure to a long-range antiferromagnetic order under pressure. A deeper understanding of itinerant-<k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><k:mi>f</k:mi></k:math>-electron magnetism in <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:mrow><m:msub><m:mrow><m:mi>UTe</m:mi></m:mrow><m:mrow><m:mn>2</m:mn></m:mrow></m:msub></m:mrow></m:math> will be a key for describing its unconventional superconducting phases. <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":"41 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184099","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":"Interplay of Nanoscale Strain and Smectic Susceptibility in Kagome Superconductors","authors":"Yidi Wang, Hong Li, Siyu Cheng, He Zhao, Brenden R. Ortiz, Andrea Capa Salinas, Stephen D. Wilson, Ziqiang Wang, Ilija Zeljkovic","doi":"10.1103/physrevx.15.021074","DOIUrl":"https://doi.org/10.1103/physrevx.15.021074","url":null,"abstract":"Exotic quantum solids can host electronic states that spontaneously break rotational symmetry of the electronic structure, such as electronic nematic phases and unidirectional charge density waves (CDWs). When electrons couple to the lattice, uniaxial strain can be used to anchor and control this electronic directionality. Here, we reveal an unusual impact of strain on unidirectional “smectic” CDW orders in kagome superconductors AV</a:mi></a:mrow>3</a:mn></a:msub>Sb</a:mi></a:mrow>5</a:mn></a:msub></a:mrow></a:math> using spectroscopic-imaging scanning tunneling microscopy. We discover local decoupling between the smectic electronic director axis and the direction of anisotropic strain. While the two can generally be aligned along the same direction in regions of a small CDW gap, the tendency for alignment decreases in regions where the CDW gap is the largest. This feature, in turn, suggests nanoscale variations in smectic susceptibility, which we attribute to a combination of local strain and electron correlation strength. Overall, we observe an unusually high decoupling rate between the smectic electronic director of the three-state Potts order and anisotropic strain, revealing weak smectoelastic coupling in the CDW phase of kagome superconductors. This finding is phenomenologically different from the extensively studied nematoelastic coupling in the Ising nematic phase of Ising nematic phase of Fe-based superconductor bulk single crystals, providing a contrasting picture of how strain can control electronic unidirectionality in different families of quantum 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":"238 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184096","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":"Electrically Driven Cascaded Photon Emission in a Single Molecule","authors":"Katharina Kaiser, Anna Rosławska, Michelangelo Romeo, Fabrice Scheurer, Tomáš Neuman, Guillaume Schull","doi":"10.1103/physrevx.15.021072","DOIUrl":"https://doi.org/10.1103/physrevx.15.021072","url":null,"abstract":"Controlling electrically stimulated quantum light sources (QLSs) is key for developing integrated and low-scale quantum devices. The underlying mechanisms leading to electrically driven quantum emission, however, are complex, as a large number of electronic states of the system can be involved and, thus, impact the emission dynamics. Here, we use a scanning tunneling microscope to electrically excite a model QLS, namely, a single ZnPc molecule, and disentangle the interplay of charge transfer and excited state formation. The luminescence spectra reveal two lines, associated to the emission of the neutral (exciton) and positively charged (trion) ZnPc, both exhibiting single-photon source behavior. In addition, we find a correlation between the charged and neutral emission, specifically, the signature of a photon cascade in which the radiative decay of the molecular trion is followed by the formation and decay of the exciton. By adjusting the charging vs discharging rate, we show that we can control these emission statistics. This generic strategy is further established by a comprehensive rate equation model comprising a variety of states that mediate excited state formation in the electrically driven single and cascaded photon emission process, revealing the complex internal dynamics of the molecular junction. <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":"35 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144176975","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":"Hybrid Quantum-Classical Stochastic Approach to Dissipative Spin-Boson Models","authors":"Naushad A. Kamar, Mohammad Maghrebi","doi":"10.1103/physrevx.15.021073","DOIUrl":"https://doi.org/10.1103/physrevx.15.021073","url":null,"abstract":"Spin-boson models involving many interacting spins and bosons are ubiquitous in quantum simulation platforms. At the same time, characterizing the dynamics of these quantum systems represents a significant challenge. Here, we consider general spin-boson models where bosons are subject to Markovian dissipation (e.g., due to cavity loss). We present an exact hybrid quantum-classical stochastic approach where the solution of a classical stochastic equation—mimicking the bosonic modes—is input into a quantum stochastic equation for the spins. Furthermore, the spins are effectively decoupled for each stochastic realization, which nevertheless comes at the expense of sampling over unphysical states. In contrast with existing stochastic approaches based on the influence functional formalism, we place no restriction (factorizability or Gaussianity) on the initial state, or the spin-boson coupling (except that it be linear in the bosonic operator). Markovian dissipation, being at the heart of our approach, renders the stochastic equations Markovian even in the strong coupling regime. Furthermore, it ensures hermiticity (though not positivity) of the density matrix for each realization, thus improving the convergence of stochastic sampling. Interestingly, we find a condition on the classical simulability of the system based solely on the single atom cooperativity even in a many-body setting. We benchmark and showcase the utility of our approach in several examples, specifically in cases where a direct numerical computation is unfeasible. <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":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144177035","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":"Universal Quantum Dynamics of Bose Polarons","authors":"Jiří Etrych, Gevorg Martirosyan, Alec Cao, Christopher J. Ho, Zoran Hadzibabic, Christoph Eigen","doi":"10.1103/physrevx.15.021070","DOIUrl":"https://doi.org/10.1103/physrevx.15.021070","url":null,"abstract":"Predicting the emergent properties of impurities immersed in a quantum bath is a fundamental challenge that can defy quasiparticle treatments. Here, we measure the spectral properties and real-time dynamics of mobile impurities injected into a weakly interacting homogeneous Bose-Einstein condensate, using two broad Feshbach resonances to tune both the impurity-bath and intrabath interactions. For attractive impurity-bath interactions, the impurity spectrum features a single branch, which away from the resonance corresponds to a well-defined attractive polaron; near the resonance, we observe dramatic broadening of this branch, suggesting a breakdown of the quasiparticle picture. For repulsive impurity-bath interactions, the spectrum features two branches: the attractive branch that is dominated by excitations with energy close to that of the Feshbach dimer, but has a many-body character, and the repulsive polaron branch. Our measurements show that the behavior of impurities in weakly interacting baths is remarkably universal, controlled only by the bath density and a single dimensionless interaction parameter. <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":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144165231","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":"Toward an Ab Initio Theory of High-Temperature Superconductors: A Study of Multilayer Cuprates","authors":"Benjamin Bacq-Labreuil, Benjamin Lacasse, A.-M. S. Tremblay, David Sénéchal, Kristjan Haule","doi":"10.1103/physrevx.15.021071","DOIUrl":"https://doi.org/10.1103/physrevx.15.021071","url":null,"abstract":"Significant progress toward a theory of high-temperature superconductivity in cuprates has been achieved via the study of effective one- and three-band Hubbard models. Nevertheless, material-specific predictions, while essential for constructing a comprehensive theory, remain challenging due to the complex relationship between real materials and the parameters of the effective models. By combining cluster dynamical mean-field theory and density functional theory in a charge-self-consistent manner, here we show that the goal of material-specific predictions for high-temperature superconductors from first principles is within reach. To demonstrate the capabilities of our approach, we take on the challenge of explaining the remarkable physics of multilayer cuprates by focusing on the two representative Ca</a:mi></a:mrow>(</a:mo>1</a:mn>+</a:mo>n</a:mi>)</a:mo></a:mrow></a:msub>Cu</a:mi></a:mrow>n</a:mi></a:mrow></a:msub></a:mrow>O</a:mi></a:mrow>2</a:mn>n</a:mi></a:mrow></a:msub>Cl</a:mi></a:mrow>2</a:mn></a:mrow></a:msub></a:mrow></a:mrow></a:mrow></a:math> and <f:math xmlns:f=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><f:mrow><f:msub><f:mrow><f:mi>HgBa</f:mi></f:mrow><f:mrow><f:mn>2</f:mn></f:mrow></f:msub></f:mrow><f:mrow><f:msub><f:mrow><f:mi>Ca</f:mi></f:mrow><f:mrow><f:mo stretchy=\"false\">(</f:mo><f:mi>n</f:mi><f:mo>−</f:mo><f:mn>1</f:mn><f:mo stretchy=\"false\">)</f:mo></f:mrow></f:msub><f:mrow><f:msub><f:mrow><f:mi>Cu</f:mi></f:mrow><f:mrow><f:mi>n</f:mi></f:mrow></f:msub></f:mrow><f:mrow><f:msub><f:mrow><f:mi mathvariant=\"normal\">O</f:mi></f:mrow><f:mrow><f:mo stretchy=\"false\">(</f:mo><f:mn>2</f:mn><f:mi>n</f:mi><f:mo>+</f:mo><f:mn>2</f:mn><f:mo stretchy=\"false\">)</f:mo></f:mrow></f:msub></f:mrow></f:mrow></f:math> families. We shed light on the microscopic origin of many salient features of multilayer cuprates, in particular, the <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:mi>n</m:mi></m:math> dependence of their superconducting properties. The growth of <o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><o:msub><o:mi>T</o:mi><o:mi>c</o:mi></o:msub></o:math> from the single-layer to the trilayer compounds is here explained by the reduction of the charge transfer gap and, consequently, the growth of superexchange <q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><q:mi>J</q:mi></q:math> as <s:math xmlns:s=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><s:mi>n</s:mi></s:math> increases. The origin of both is traced to the appearance of low-energy conduction bands reminiscent of standing wave modes confined within the stack of <u:math xmlns:u=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><u:mrow><u:msub><u:mrow><u:mi>CuO</u:mi></u:mrow><u:mrow><u:mn>2</u:mn></u:mrow></u:msub></u:mrow></u:math> planes. We interpret the ultimate drop of <w:math xmlns:w=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><w:msub><w:mi>T</w:mi><w:mi>c</w:mi></w:msub></w:m","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"58 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144165230","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":"Exciton Self-Trapping in Twisted Hexagonal Boron Nitride homostructures","authors":"Sébastien Roux, Christophe Arnold, Etienne Carré, Alexandre Plaud, Lei Ren, Frédéric Fossard, Nicolas Horezan, Eli Janzen, James H. Edgar, Camille Maestre, Bérangère Toury, Catherine Journet, Vincent Garnier, Philippe Steyer, Takashi Taniguchi, Kenji Watanabe, Cédric Robert, Xavier Marie, François Ducastelle, Annick Loiseau, Julien Barjon","doi":"10.1103/physrevx.15.021067","DOIUrl":"https://doi.org/10.1103/physrevx.15.021067","url":null,"abstract":"One of the main interests of 2D materials is their ability to be assembled with many degrees of freedom for tuning and manipulating excitonic properties. There is a need to understand how the structure of the interfaces between atomic layers influences exciton properties. Here we use cathodoluminescence and time-resolved cathodoluminescence experiments to study how excitons interact with the interface between two twisted hexagonal boron nitride (h</a:mi></a:mrow></a:math>-BN) crystals with various angles. An efficient capture of free excitons by the interface is demonstrated, which leads to a population of long-lived and interface-localized (2D) excitons. Temperature-dependent experiments indicate that for high twist angles, these excitons localized at the interface further undergo a self-trapping. It consists in a distortion of the lattice around the exciton on which the exciton traps itself. Our results suggest that this exciton-interface interaction causes the broad 4-eV optical emission of highly twisted <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mi>h</c:mi></c:mrow></c:math>-BN–<e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mi>h</e:mi></e:mrow></e:math>-BN structures. Exciton self-trapping is finally discussed as a common feature of <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mi>s</g:mi><g:msup><g:mi>p</g:mi><g:mn>2</g:mn></g:msup></g:math> hybridized boron nitride polytypes and nanostructures due to the ionic nature of the B—N bond and the small size of their excitons. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"33 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154195","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":"High-Fidelity Electron Spin Gates for Scaling Diamond Quantum Registers","authors":"T. Joas, F. Ferlemann, R. Sailer, P. J. Vetter, J. Zhang, R. S. Said, T. Teraji, S. Onoda, T. Calarco, G. Genov, M. M. Müller, F. Jelezko","doi":"10.1103/physrevx.15.021069","DOIUrl":"https://doi.org/10.1103/physrevx.15.021069","url":null,"abstract":"Diamond is a promising platform for quantum information processing as it can host highly coherent qubits that could allow for the construction of large quantum registers. A prerequisite for such devices is a coherent interaction between nitrogen-vacancy (NV) electron spins enabling scalable entanglement. Entanglement between dipolar-coupled NV spin pairs has been demonstrated but with a limited fidelity, and its error sources have not been characterized. Here, we design and implement a robust two-qubit gate between NV electron spins in diamond and quantify the influence of multiple error sources on the gate performance. Experimentally, we demonstrate a record gate fidelity of F</a:mi></a:mrow>2</a:mn>q</a:mi></a:mrow></a:msub>=</a:mo>(</a:mo>96.0</a:mn>±</a:mo>2.5</a:mn>)</a:mo>%</a:mi></a:mrow></a:math> under ambient conditions. Our identification of the dominant errors paves the way towards NV-NV gates beyond the error correction threshold. <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":"19 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154303","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":"“Morphogenetic Action” Principle for 3D Shape Formation by the Growth of Thin Sheets","authors":"Dillon J. Cislo, Anastasios Pavlopoulos, Boris I. Shraiman","doi":"10.1103/physrevx.15.021068","DOIUrl":"https://doi.org/10.1103/physrevx.15.021068","url":null,"abstract":"How does growth encode form in developing organisms? Many different spatiotemporal growth profiles may sculpt tissues into the same target 3D shapes, but only specific growth patterns are observed in animal and plant development. In particular, growth profiles may differ in their degree of spatial variation and growth anisotropy; however, the criteria that distinguish observed patterns of growth from other possible alternatives are not understood. Here we exploit the mathematical formalism of quasiconformal transformations to formulate the problem of “growth pattern selection” quantitatively in the context of 3D shape formation by growing 2D epithelial sheets. We propose that nature settles on growth patterns that are the “simplest” in a certain way. Specifically, we demonstrate that growth pattern selection can be formulated as an optimization problem and solved for the trajectories that minimize spatiotemporal variation in areal growth rates and deformation anisotropy. The result is a complete prediction for the growth of the surface, including not only a set of intermediate shapes, but also a prediction for cell displacement along those surfaces in the process of growth. Optimization of growth trajectories for both idealized surfaces and those observed in nature show that relative growth rates can be uniformized at the cost of introducing anisotropy. Minimizing the variation of programmed growth rates can therefore be viewed as a generic mechanism for growth pattern selection and may help us to understand the prevalence of anisotropy in developmental programs. <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":"3 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154197","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}