bluuebunny/crossref_metadata_2025 huggingface dataset:
Local Gene Duplications Drive Extensive NLR Copy Number Variation Across Multiple Genotypes ofTheobroma cacao
Authors: Winters Noah P. , Wafula Eric K. , Timilsena Prakash R. , Ralph Paula E. , Maximova Siela N. , de Pamphilis Claude W. , Guiltinan Mark J. , Marden James H.
Published: September 2024

Nucleotide-binding leucine rich repeat receptors (NLR) are an essential component of plant immunity. NLR evolution is complex and dynamic, with rapid expansions, contractions, and polymorphism. Hundreds of high-quality plant genomes generated over the last two decades provide substantial insight into the evolutionary dynamics of NLR genes. Despite steadily decreasing sequencing costs, the difficulty of sequencing, assembling, and annotating high-quality genomes has resulted in comparatively little genome-wide information on intraspecies NLR diversity. In this study, we investigated the evolution of NLR genes across 11 high-quality genomes of the chocolate tree,Theobroma cacaoL. We found 3-fold variation in NLR copy number across genotypes, a pattern driven primarily by expansion of NLR clusters via tandem and proximal duplication. Our results indicate local duplications can radically reshape gene families over short evolutionary time scales, creating extensive intraspecific variation and a source of NLR diversity that could be utilized to enrich our understanding of both plant-pathogen interactions and resistance breeding.
Neuroimaging Biomarkers in Addiction
Authors: Ekhtiari Hamed , Sangchooli Arshiya , Carmichael Owen , Moeller Gerard , ODonnell Patricio , Oquendo Maria , Paulus Martin P. , Pizzagalli Diego A. , Ramey Tatiana , Schacht Joseph , Zare-Bidoky Mehran , Childress Anna Rose , Brady Kathleen
Published: September 2024

As a neurobiological process, addiction involves pathological patterns of engagement with substances and a range of behaviors with a chronic and relapsing course. Neuroimaging technologies assess brain activity, structure, physiology, and metabolism at scales ranging from neurotransmitter receptors to large-scale brain networks, providing unique windows into the core neural processes implicated in substance use disorders. Identified aberrations in the neural substrates of reward and salience processing, response inhibition, interoception, and executive functions with neuroimaging can inform the development of pharmacological, neuromodulatory, and psychotherapeutic interventions to modulate the disordered neurobiology. Based on our systematic search, 409 protocols registered on ClinicalTrials.gov include the use of one or more neuroimaging paradigms as an outcome measure in addiction, with the majority (N=268) employing functional magnetic resonance imaging (fMRI), followed by positron emission tomography (PET) (N=71), electroencephalography (EEG) (N=50), structural magnetic resonance imaging (MRI) (N=35) and magnetic resonance spectroscopy (MRS) (N=35). Furthermore, in a PubMed systematic review, we identified 61 meta-analyses including 30 fMRI, 22 structural MRI, 8 EEG, 7 PET, and 3 MRS meta-analyses suggesting potential biomarkers in addictions. These studies can facilitate the development of a range of biomarkers that may prove useful in the arsenal of addiction treatments in the coming years. There is evidence that these markers of large-scale brain structure and activity may indicate vulnerability or separate disease subtypes, predict response to treatment, or provide objective measures of treatment response or recovery. Neuroimaging biomarkers can also suggest novel targets for interventions. Closed or open loop interventions can integrate these biomarkers with neuromodulation in real-time or offline to personalize stimulation parameters and deliver the precise intervention. This review provides an overview of neuroimaging modalities in addiction, potential neuroimaging biomarkers, and their physiologic and clinical relevance. Future directions and challenges in bringing these putative biomarkers from the bench to the bedside are also discussed.
LLM-AIx: An open source pipeline for Information Extraction from unstructured medical text based on privacy preserving Large Language Models
Authors: Wiest Isabella Catharina , Wolf Fabian , Leßmann Marie-Elisabeth , van Treeck Marko , Ferber Dyke , Zhu Jiefu , Boehme Heiko , Bressem Keno K. , Ulrich Hannes , Ebert Matthias P. , Kather Jakob Nikolas
Published: September 2024

In clinical science and practice, text data, such as clinical letters or procedure reports, is stored in an unstructured way. This type of data is not a quantifiable resource for any kind of quantitative investigations and any manual review or structured information retrieval is time-consuming and costly. The capabilities of Large Language Models (LLMs) mark a paradigm shift in natural language processing and offer new possibilities for structured Information Extraction (IE) from medical free text. This protocol describes a workflow for LLM based information extraction (LLM-AIx), enabling extraction of predefined entities from unstructured text using privacy preserving LLMs. By converting unstructured clinical text into structured data, LLM-AIx addresses a critical barrier in clinical research and practice, where the efficient extraction of information is essential for improving clinical decision-making, enhancing patient outcomes, and facilitating large-scale data analysis.

The protocol consists of four main processing steps: 1) Problem definition and data preparation, 2) data preprocessing, 3) LLM-based IE and 4) output evaluation. LLM-AIx allows integration on local hospital hardware without the need of transferring any patient data to external servers. As example tasks, we applied LLM-AIx for the anonymization of fictitious clinical letters from patients with pulmonary embolism. Additionally, we extracted symptoms and laterality of the pulmonary embolism of these fictitious letters. We demonstrate troubleshooting for potential problems within the pipeline with an IE on a real-world dataset, 100 pathology reports from the Cancer Genome Atlas Program (TCGA), for TNM stage extraction. LLM-AIx can be executed without any programming knowledge via an easy-to-use interface and in no more than a few minutes or hours, depending on the LLM model selected.
Association of the rs738409 polymorphism inPNPLA3with development and severity of non-alcoholic fatty liver disease in ethnic Bengali population of West Bengal
Authors: Das Mousumi , Biswas Arindam , Goswami Soumik , Deb Rajat , Das Sukdeb , Ray Debes
Published: September 2024

Background and Objectives

Non-alcoholic Fatty Liver Disease (NAFLD) is a common disorder with a complex etiology. Polymorphic variant rs738409 (Ile148Met) in thePNPLA3gene has been reported to be associated with NAFLD among several ethnic populations. The present study aims to identify the potential association of this PNPLA3 gene variant with NAFLD among the ethnic Bengali population of West Bengal and correlate it with disease severity and biochemical parameters.

Materials and Methods

The Ile148Met variant was genotyped among 99 clinically diagnosed NAFLD cases and 100 ethnicity-matched controls from West Bengal using PCR-RFLP-based techniques.

Results

We identify statistically significant differences in genotype and allele frequencies of rs738409 between NAFLD cases and controls (P = 0.001 & 0.0057). The frequency distribution of risk genotype (GG) and risk allele (G allele) was significantly associated with a higher FIB-4 score (P = 0.0251) and Controlled Attenuation Parameter (CAP) score (P = 0.0072) but not with Liver Stiffness Measurement (LSM) value. The mean CAP score was significantly higher among the risk allele (G allele) carrier than the ‘C’ allele carrier (272.49±51.99 vs 247.38±49.46; P = 0.0328). In patients with NAFLD, the CC genotype was associated with a higher level of total bilirubin (P = 0.0189).

Conclusion

The Ile148Met variant of thePNPLA3gene is a predisposing risk factor for the development of NAFLD and is associated with increased severity of hepatic steatosis among the ethnic Bengali population of West Bengal.
Inferring Ligand-Receptor Interactions between neuronal subtypes during mouse cortical development
Authors: Mathieu Remi , Corbieres Lea , Draia-Nicolau Tangra , Govindan Annousha , Bensa Vianney , Pallesi-Pocachard Emilie , Silvagnoli Lucas , Represa Alfonso , Cardoso Carlos , Telley Ludovic , de Chevigny Antoine
Published: September 2024

The cerebral cortex hosts a diverse array of excitatory glutamatergic and inhibitory GABAergic neuron types, each characterized by distinct positional and synaptic connectivity patterns. However, the molecular mechanisms orchestrating this precise organization remain largely unknown. To identify ligand-receptor (LR) pairs regulating interactions and connectivity among cortical neurons during embryonic and postnatal development, we analyzed the transcriptional dynamics of all genes across major cortical neuron subtypes at 17 developmental time points using single-cell transcriptomics. From these data, we constructed a comprehensive bioinformatic atlas that inferred significant LR-mediated interactions between glutamatergic and GABAergic neurons throughout cortical maturation. This atlas not only corroborated known interactions but also enabled the discovery of novel regulators, identifying two cadherin superfamily members as key mediators of perisomatic inhibition in deep and superficial layer excitatory neurons by parvalbumin-expressing basket cells. These findings underscore the power of large-scale transcriptional profiling to unravel fundamental molecular mechanisms driving cortical circuit assembly.
Unraveling genetic load dynamics during biological invasion: insights from two invasive insect species
Authors: Lombaert Eric , Blin Aurelie , Porro Barbara , Guillemaud Thomas , Bernal Julio S , Chang Gary , Kirichenko Natalia , Sappington Thomas W , Toepfer Stefan , Deleury Emeline
Published: September 2024

Many invasive species undergo a significant reduction in genetic diversity, i.e. a genetic bottleneck, in the early stages of invasion. However, this reduction does not necessarily prevent them from achieving considerable ecological success and becoming highly efficient colonizers. Here we investigated the purge hypothesis, which suggests that demographic bottlenecks may facilitate conditions (e.g., increased homozygosity and inbreeding) under which natural selection can purge deleterious mutations, thereby reducing genetic load. We used a transcriptome-based exome capture protocol to identify thousands of SNPs in coding regions of native and invasive populations of two highly successful invasive insect species, the western corn rootworm (Chrysomelidae: Diabrotica virgifera virgifera) and the harlequin ladybird (Coccinelidae: Harmonia axyridis). We categorized and polarized SNPs to investigate changes in genetic load between invasive populations and their sources. Our results differed between species. In D. virgifera virgifera, although there was a general reduction in genetic diversity in invasive populations, including that associated with genetic load, we found no clear evidence for purging of genetic load, except marginally for highly deleterious mutations in one European population. Conversely, in H. axyridis, the reduction in genetic diversity was minimal, and we detected signs of genetic load fixation in invasive populations. These findings provide new insights into the evolution of genetic load during invasions, but do not offer a definitive answer to the purge hypothesis. Future research should include larger genomic datasets and a broader range of invasive species to further elucidate these dynamics.
Toll-like receptor-1 (TLR-1) activation reduces immunoglobulin free light chain production by multiple myeloma cells in the context of bone marrow stromal cells and fibronectin
Authors: Abdi Jahan , Redegeld Frank
Published: September 2024

Studies over the past years have provided evidence that Toll-like receptor (TLRs) activation in multiple myeloma (MM) cells induces heterogeneous functional responses including cell growth and proliferation, survival or apoptosis. These effects have been suggested to be partly due to increase in secretion of cytokines such as IL-6 or IFNα among others from MM cells following TLR activation. However, whether triggering of these receptors also modulates production of immunoglobulin free light chains (FLCs) in MM cells has never been investigated. FLCs contribute largely to MM pathology. Here we explored the effect of TLR1 ligand (Pam3CSK4) alone or combined with bortezomib (BTZ) on production of FLCs in human myeloma cell lines, L363, OPM-2, U266 and NCI-H929 in the absence or presence of bone marrow stromal cells (BMSCs) or fibronectin (FN) to examine the influence of bone marrow microenvironment. Adhesion to BMSCs or FN increased secretion of FLC in MM cells. Pam3CSK4 decreased FLC production in the presence or absence of BMSCs or FN and this effect was enhanced in combination with BTZ. However, the level of reduction was lower in the presence of BMSCs or FN. Our findings imply that activation of TLR1 downregulates FLC production in MM cells even in the context of bone marrow microenvironment components and suggest that some TLRs such as TLR1 might be considered a therapeutic target especially in combined treatment protocols in MM.
An Efficient Direct Conversion Strategy to Generate Functional Astrocytes from Human Adult Fibroblasts
Authors: Bhaskar Uchit , Shrimpton Emily , Ayo Jason , Prasla Asiya , Kos Mark Z , Carless Melanie A.
Published: September 2024

Direct reprogramming approaches offer an attractive alternative to stem-cell-derived models, allowing the retention of epigenetic information and age-associated cellular phenotypes, and providing an expedited method to generate target cell types. Several groups have previously generated multiple neuronal subtypes, neural progenitor cells, oligodendrocytes, and other cell types directly from fibroblasts. However, while some groups have had success at the efficient conversion ofembryonicfibroblasts to astrocytes, they have not yet achieved similar conversion efficiency foradulthuman fibroblasts. To generate astrocytes for the study of adult-stage disorders, we developed an improved direct conversion strategy employing a combination of small molecules to activate specific pathways that induce trans-differentiation of human adult fibroblasts to astrocytes. We demonstrate that this method produces mature GFAP+/S100β+ cells at high efficiency (40-45%), comparable to previous studies utilizing embryonic fibroblasts. Further,Fibroblast-derived inducedAstrocytes (FdiAs) are enriched for markers of astrocyte functionality, including ion-channel buffering, gap-junction communication, and glutamate uptake; and exhibit astrocyte-like calcium signaling and neuroinflammatory phenotypes. RNA-Seq analysis indicates a close correlation to human brain astrocytes and iPSC-derived astrocyte models. Fibroblast-derived induced astrocytes provide a useful tool in studying the adult brain and complement existingin vitromodels of induced neurons (iNs), providing an additional platform to study adult-stage brain disorders.
Universality of Efimov states in highly mass-imbalanced cold-atom mixtures with van der Waals and dipole interactions
Authors: Oi Kazuki , Naidon Pascal , Endo Shimpei
Published: September 2024

We study three-body systems in a mass-imbalanced, two-component, cold-atom mixture, and we investigate the three-body parameter of their Efimov states for both bosonic and fermionic systems, with a major focus on the Er-Er-Li Efimov states. For a system interacting solely via van der Waals interactions, the van der Waals universality of the three-body parameter is analytically derived using the quantum defect theory. With the addition of a perturbative dipole interaction between the heavy atoms, the three-body parameters of the bosonic and fermionic Efimov states are found to behave differently. When the dipole interaction is as strong as the van der Waals interaction, corresponding to realistic Er-Er-Li Efimov states, we show that the van der Waals universality persists once the effects of the nonperturbative dipole interaction are into the s-wave and p-wave scattering parameters between the heavy atoms. For a dipole interaction much stronger than the van der Waals interaction, we find that the universality of the Efimov states can be alternatively characterized by a quasi-one-dimensional scattering parameter due to a strong anisotropic deformation of the Efimov wave functions. Our work thus clarifies the interplay of isotropic and anisotropic forces in the universality of the Efimov states. Based on the renormalized van der Waals universality, the three-body parameter is estimated for specific isotopes of Er-Li cold-atom mixtures.

Published by the American Physical Society
2024
Nyquist-compliant cycloidal computed tomography
Authors: Lioliou G. , Charman A. , Roche i Morgó O. , Endrizzi M. , Arridge S. , Bate D. , Olivo A. , Hagen C.
Published: September 2024

Cycloidal computed tomography, by which a lateral sample translation and rotation are combined, is a fully-fly-scan-compatible acquisition scheme for micro-computed-tomography systems using amplitude-modulated beams. Such systems have gained popularity, as they enable x-ray phase-contrast imaging (XPCI) and aperture-driven spatial resolution. The former provides superior contrast for weakly attenuating samples, while the latter allows the resolution of a micro-computed-tomography system to be increased beyond the conventional limit dictated by the source and detector. Such systems initially required time-inefficient step-and-shoot acquisitions, a limitation that has been removed by the development of cycloidal computed tomography. Here we derive cycloidal sampling conditions that are optimal in the sense of the Nyquist-Shannon theorem. Their availability enables the acquisition of well-sampled (i.e., high-resolution) XPCI images in a time-efficient manner, a long-sought outcome with relevance to laboratory implementations, where scan times have traditionally been long, and to synchrotron implementations, where the next frontier is to achieve high-speed (e.g., dynamic) imaging. We make no assumptions on the type of x-ray source used, but demonstrate the optimal conditions with a rotating-anode x-ray tube.

Published by the American Physical Society
2024
(C5H9NH3)2CuBr4
: A metal-organic two-ladder quantum magnet
Authors: Philippe J. , Elson F. , Casati N. P. M. , Sanz S. , Metzelaars M. , Shliakhtun O. , Forslund O. K. , Lass J. , Shiroka T. , Linden A. , Mazzone D. G. , Ollivier J. , Shin S. , Medarde M. , Lake B. , Månsson M. , Bartkowiak M. , Normand B. , Kögerler P. , Sassa Y. , Janoschek M. , Simutis G.
Published: September 2024

Low-dimensional quantum magnets are a versatile materials platform for studying the emergent many-body physics and collective excitations that can arise even in systems with only short-range interactions. Understanding their low-temperature structure and spin Hamiltonian is key to explaining their magnetic properties, including unconventional quantum phases, phase transitions, and excited states. We study the metal-organic coordination compound (C5H9NH3)2CuBr4 and its deuterated counterpart, which upon its discovery was identified as a candidate two-leg quantum (S=12) spin ladder in the strong-leg coupling regime. By growing large single crystals and probing them with both bulk and microscopic techniques, we deduce that two previously unknown structural phase transitions take place between 136 and 113 K. The low-temperature structure has a monoclinic unit cell that gives rise to two inequivalent spin ladders. We further confirm the absence of long-range magnetic order down to 30 mK and investigate the implications of this two-ladder structure for the magnetic properties of (C5H9NH3)2CuBr4 by analyzing our own specific-heat and susceptibility data.

Published by the American Physical Society
2024
Peculiarities of the Landau level collapse in graphene ribbons in crossed magnetic and in-plane electric fields
Authors: Herasymchuk A. A. , Sharapov S. G. , Gusynin V. P.
Published: September 2024

Employing the low-energy effective theory alongside a combination of analytical and numerical techniques, we explore the Landau level collapse phenomenon, uncovering previously undisclosed features. We consider both finite-width graphene ribbons and semi-infinite geometries subjected to a perpendicular magnetic field and an in-plane electric field, applied perpendicular to both zigzag and armchair edges. In the semi-infinite geometry the hole (electron)-like Landau levels collapse as the ratio of electric and magnetic fields reaches the critical value +(−)1. On the other hand, the energies of the electron (hole)-like levels remain distinct near the edge and deeply within the bulk, approaching each other asymptotically for the same critical value. In the finite geometry, we show that the electron (hole)-like levels become denser and merge, forming a band.

Published by the American Physical Society
2024
Irrational Moments and Signatures of Higher-Rank Gauge Theories in Diluted Classical Spin Liquids
Authors: Flores-Calderón R. , Benton Owen , Moessner Roderich
Published: September 2024

Classical spin liquids (CSLs) have proved to be a fruitful setting for the emergence of exotic gauge theories. Vacancy clusters in CSLs can introduce gauge charges into the system, and the resulting behavior in turn reveals the nature of the underlying theory. We study these effects for a series of CSLs on the honeycomb lattice. We find that dilution leads to the emergence of effective free spins with tuneable, and generally irrational, size. For a specific higher-rank CSL, described by a symmetric tensor gauge fields, dilution produces spin textures with a characteristic quadrupolar angular structure and infinite-ranged interactions between dilution clusters.

Published by the American Physical Society
2024
Dynamical Fluctuations of Random Walks in Higher-Order Networks
Authors: Di Gaetano Leonardo , Carugno Giorgio , Battiston Federico , Coghi Francesco
Published: September 2024

Although higher-order interactions are known to affect the typical state of dynamical processes giving rise to new collective behavior, how they drive the emergence of rare events and fluctuations is still an open problem. We investigate how fluctuations of a dynamical quantity of a random walk exploring a higher-order network arise over time. In the quenched case, where the hypergraph structure is fixed, through large deviation theory we show that the appearance of rare events is hampered in nodes with many higher-order interactions, and promoted elsewhere. Dynamical fluctuations are further boosted in an annealed scenario, where both the diffusion process and higher-order interactions evolve in time. Here, extreme fluctuations generated by optimal higher-order configurations can be predicted in the limit of a saddle-point approximation. Our study lays the groundwork for a wide and general theory of fluctuations and rare events in higher-order networks.

Published by the American Physical Society
2024
Nonclassical coincidences of atomic and mechanical excitations
Authors: Manukhova Alisa D. , Rakhubovsky Andrey A. , Filip Radim
Published: September 2024

Hybrid systems hold promise to provide an advantage in future quantum technology. Operating such systems outside the classical regime is crucially important to fully realize their potential. We investigate a pulsed quantum nondemolition gate between a cloud of atoms and a mechanical oscillator in distant cavities and demonstrate that this gate is capable of producing nonclassical coincidences of excitations in the disparate subsystems interacting by light. The nonclassicality is justified by evaluation of excitations created simultaneously in both modes beyond any joint classical states of such subsystems. To test the result, we use a nonclassicality witness based on available homodyne tomography of the atomic and mechanical states. Using feasible parameters, we show that it is possible to turn the pulsed dynamics of the state-of-the-art systems into nonclassical coincidences, and illustrate it for the cases of the atom-light, optomechanical, and atom-mechanical hybrid interactions. These tests are necessary to open full investigation of quantum correlations in hybrid systems.

Published by the American Physical Society
2024
Weyl fermion excitations in the ideal Weyl semimetal
CuTlSe2
Authors: Wang C. N. , Tay D. , Dong Q. X. , Okvátovity Z. , Huddart B. M. , Ma C. Y. , Yokoyama K. , Yu L. , Lancaster T. , Chen G. F. , Ott H.-R. , Shiroka T.
Published: September 2024

An ideal Weyl semimetal is characterized by a dispersion in which only Weyl cones intersect the Fermi level, with low-energy behavior being governed by Weyl fermions. Although ideal Weyl semimetals have long been anticipated, only a few are realized in nonmagnetic materials. In this study, we confirm the presence of Weyl-fermion excitations in the ideal Weyl semimetal CuTlSe2 via a combination of magnetoresistance, Hall-effect, magnetic-susceptibility, nuclear magnetic resonance (NMR), and muon-spin relaxation (µSR) experiments. Magnetoresistance measurements reveal a negative longitudinal magnetoresistance (LMR), which scales as B2, while Hall-effect results indicate a predominant contribution from Weyl fermions with a hole-type charge. Magnetic susceptibility and µSR measurements indicate the lack of any intrinsic spontaneous magnetic moments down to base temperature. Finally, the NMR results can be modeled by a two-component effective Hamiltonian, which reproduces well the temperature-dependent Cu63 NMR (T1T)−1 factor, shown to scale as T2 below 100 K and as T1 above 100 K. Overall, we find that the extremely low concentration (1017cm−3) of carriers in CuTlSe2 originates from an ideal nonmagnetic Weyl semimetallic state, persisting up to a thermal excitation energy of 9 meV (100 K), above which trivial electronic bands close to EF take over. Our findings highlight CuTlSe2 as a new member of the intriguing class of Weyl semimetals.

Published by the American Physical Society
2024
Role of polaron dressing in superradiant emission dynamics
Authors: Wiercinski J. , Cygorek M. , Gauger E. M.
Published: September 2024

Cooperative effects of multiple quantum emitters are characterized by transitions via delocalized collective states with altered emission properties due to the existence of interemitter coherences. When realized with excitonic condensed-matter nanostructures, these effects are significantly affected by the presence of strong emitter-phonon coupling, which leads to the formation of polarons. We show that, while for single-emitter emission into free space this formation has no impact on its radiative lifetime, the same is not true for superradiant emission. Considering the case of two indistinguishable quantum emitters, we analyze how polaron dressing affects collective photon emission by mixing bright and dark Dicke states. Our numerical simulations show that this mixing crucially depends on the circumstances of the excitation of the system: Depending on the pulse length of an exciting laser, one can choose to either prepare polaronic Dicke states, or bare electronic Dicke states, changing the superradiant decay characteristics of the system. Additionally, we derive analytic expressions for these limiting cases, which match the results of numerically exact calculations.

Published by the American Physical Society
2024
Simple tensorial theory of smectic C liquid crystals
Authors: Xia Jingmin , Han Yucen
Published: September 2024

The smectic C (smC) phase represents a unique class of liquid crystal phases characterized by the layered arrangement of molecules with orientations with respect to layer normals. Building upon the real-valued tensorial smectic A (smA) model in Xia [], we propose a continuum mathematical model for smC (and smA) by introducing a coupling term between the real tensor containing orientational information and density variation to control the tilt angle between directors and the layer normal (the tilt angle is zero for smA and nonzero for smC). To validate our proposed model, we conduct a series of two- and three-dimensional numerical experiments that account for typical structures in smectics: chevron patterns, defects, dislocations, and toroidal focal conic domains. These results also reveal the phenomenological differences between smA and smC configurations.

Published by the American Physical Society
2024
Resolved-sideband cooling of a single
Be+9
ion in a cryogenic multi-Penning-trap for discrete symmetry tests with (anti-)protons
Authors: Cornejo Juan M. , Brombacher Johannes , Coenders Julia A. , von Boehn Moritz , Meiners Teresa , Niemann Malte , Ulmer Stefan , Ospelkaus Christian
Published: September 2024

Manipulating the motion of individual trapped ions at the single quantum level has become standard practice in radio-frequency ion traps, enabling sweeping advances in quantum information processing and precision metrology. The key step for motional-state engineering is ground-state cooling. Full motional control also bears great potential to explore another regime of sensitivities for fundamental physics tests in Penning traps. Here we demonstrate the key enabling step by implementing resolved-sideband cooling on the axial mode of a single Be+9 ion in a 5 Tesla cryogenic Penning trap. The system has been developed for the implementation of high-precision antimatter experiments to test the fundamental symmetries of the standard model with the highest accuracy in the baryonic sector. We measure an axial phonon number of n¯z=0.10(4) after cooling and demonstrate that the axial heating rate in our system is compatible with the implementation of quantum logic spectroscopy of (anti-)protons.

Published by the American Physical Society
2024
Entanglement generation from athermality
Authors: de Oliveira Junior A. , Son Jeongrak , Czartowski Jakub , Ng Nelly H. Y.
Published: September 2024

We investigate the thermodynamic constraints on the pivotal task of entanglement generation using out-of-equilibrium states through a model-independent framework with minimal assumptions. We establish a necessary and sufficient condition for a thermal process to generate bipartite qubit entanglement, starting from an initially separable state. Consequently, we identify the set of system states that cannot be entangled, when no external work is invested. In the regime of infinite temperature, we analytically construct this set; while for finite temperature, we provide a simple criterion to verify whether any given initial state is or is not entangleable. Furthermore, we provide an explicit construction of the future thermal cone of entanglement—the set of entangled states that a given separable state can thermodynamically evolve to. We offer a detailed discussion on the properties of this cone, focusing on the interplay between entanglement and its volumetric properties. We conclude with several key remarks on the generation of entanglement beyond two-qubit systems, and discuss its dynamics in the presence of dissipation.

Published by the American Physical Society
2024
Uniqueness of Landau levels and their analogs with higher Chern numbers
Authors: Mera Bruno , Ozawa Tomoki
Published: September 2024

Landau levels are the eigenstates of a charged particle in two dimensions under a magnetic field and are at the heart of the integer and fractional quantum Hall effects, which are two prototypical phenomena showing topological features. Following recent discoveries of fractional quantum Hall phases in van der Waals materials, there is a rapid progress in understanding of the precise condition under which the fractional quantum Hall phases can be stabilized. It is now understood that the key to obtaining the fractional quantum Hall phases is the energy band whose eigenstates are holomorphic functions in both real and momentum space coordinates. Landau levels are indeed examples of such energy bands with an additional special property of having flat geometrical features. In this paper, we prove that, in fact, the only energy eigenstates having holomorphic wave functions with a flat geometry are the Landau levels and their higher Chern number analogs. Since it has been known that any holomorphic eigenstates can be constructed from the ones with a flat geometry such as the Landau levels, our uniqueness proof of the Landau levels allows one to construct any possible holomorphic eigenstate with which the fractional quantum Hall phases can be stabilized.

Published by the American Physical Society
2024
Resonant-force-induced symmetry breaking in a quantum parametric oscillator
Authors: Boneß D. K. J. , Belzig W. , Dykman M. I.
Published: September 2024

A parametrically modulated oscillator has two opposite-phase vibrational states at half the modulation frequency. An extra force at the vibration frequency breaks the symmetry of the states. The effect can be extremely strong due to the interplay between the force and the quantum fluctuations resulting from the coupling of the oscillator to a thermal bath. The force changes the rates of the fluctuation-induced walk over the quantum states of the oscillator. If the number of the states is large, then the effect accumulates to an exponentially large factor in the rate of switching between the vibrational states. We find the factor and analyze it in the limiting cases, including the prebifurcation regime where the system is close but not too close to the bifurcation point.

Published by the American Physical Society
2024
Three-gap superconductivity with
Tc
above 80 K in hydrogenated 2D monolayer LiBC
Authors: Liu Hao-Dong , Wang Bao-Tian , Fu Zhen-Guo , Lu Hong-Yan , Zhang Ping
Published: September 2024

Although the metallization of semiconductor bulk LiBC has been experimentally achieved, various flaws, including the strong lattice distortion, the uncontrollability of phase transition under pressure, usually appear. In this work, based on the first-principles calculations, we propose a new way of hydrogenation to realize metallization. Using the fully anisotropic Migdal-Eliashberg theory, we investigate the superconducting behaviors in the stable monolayers LiBCH and LiCBH, in which C and B atoms are hydrogenated, respectively. Our findings indicate that the monolayers possess the high Tc of 82.0 and 82.5 K, respectively, along with the interesting three-gap superconducting natures. The Fermi sheets showing the obvious three-region distribution characteristics and the abnormally strong electron-phonon coupling are responsible for the high-Tc three-gap superconductivity. Furthermore, the Tc can be dramatically boosted up to 120.0 K under 3.5% tensile strain. To a great extent, the high Tc is beyond the liquid nitrogen temperature (77 K), which is beneficial for the applications in future experiments. This study not only explores the superconducting properties of the monolayers LiBCH and LiCBH, but also offers practical insights into the search for high-Tc superconductors.

Published by the American Physical Society
2024
Relaxation and fluctuations of a mass- and dipole-conserving stochastic lattice gas
Authors: Meerson Baruch
Published: September 2024

Han [] have recently introduced a classical stochastic lattice gas model which, in addition to particle conservation, also conserves the particles' dipole moment. Because of its intrinsic nonlinearity this model exhibits unusual macroscopic scaling behaviors, different from those of lattice gases that conserve only the number of particles. Here we investigate some basic relaxation and fluctuation properties of this model at large scales and at long times. These properties crucially depend on whether the total number of particles is infinite or finite. We find similarity solutions, describing relaxation of the dipole-conserving gas (DCG) in several standard settings. A major part of our effort is an extension to this model of the macroscopic fluctuation theory (MFT), previously developed for lattice gases where only the number of particles is conserved. We apply the MFT to the calculation of the variance of nonequilibrium fluctuations of the excess number of particles on the positive semi-axis when starting from an (either deterministic, or random) constant density at t=0. Using the MFT, we also identify the equilibrium Boltzmann-Gibbs distribution for the DCG. Finally, based on these results, we determine the probability distribution of, and the most probable density history leading to, a large deviation in the form of a macroscopic void of a given size in an initially uniform DCG at equilibrium.

Published by the American Physical Society
2024
Local-time formula for dissipation in solid ionic electrolytes
Authors: Rodin A. , Olsen B. A. , Ustyuzhanin A. , Maevskiy A. , Noori K.
Published: September 2024

When ions move through solids, they interact with the solid's constituent atoms and cause them to vibrate around their equilibrium points. This vibration, in turn, modifies the potential landscape through which the mobile ions travel. Because the present-time potential depends on past interactions, the coupling is inherently nonlocal in time, making its numerical and analytical treatment challenging. For sufficiently slow-moving ions, we linearize the phonon spectrum to show that these nonlocal effects can be ignored, giving rise to a draglike force. Unlike the more familiar drag coefficient in liquids, the drag takes on a matrix form due to the crystalline structure of the framework. We numerically simulate trajectories and dissipation rates using both the time-local and nonlocal formulas to validate our simplification. The time-local formula dramatically reduces the computational cost of calculating the motion of a mobile particle through a crystalline framework and clearly connects the properties of the material to the drag experienced by the particle.

Published by the American Physical Society
2024
Phase modulation of directed transport, energy diffusion, and quantum scrambling in a Floquet non-Hermitian system
Authors: Zhao Wen-Lei , Li Guanling , Liu Jie
Published: September 2024

We investigate both analytically and numerically the wavepacket's dynamics in momentum space for a Floquet non-Hermitian system with a periodically kicked driven potential. We have deduced the exact expression of a time-evolving wavepacket under the condition of quantum resonance. With this analytical expression, we can investigate thoroughly the temporal behaviors of the directed transport, mean energy, and quantum scrambling. We find interestingly that, by tuning the relative phase between the real part and imaginary part of the kicking potential, one can manipulate the directed transport, mean energy, and quantum scrambling efficiently: When the phase equals to π/2, we observe a maximum directed transport and mean energy, while a minimum scrambling phenomenon protected by the PT symmetry; when the phase is π, both the directed transport and the time dependence of the energy are suppressed; in contrast, the quantum scrambling is enhanced by the non-Hermiticity. For the quantum nonresonance case, we numerically find that the quantum interference effects lead to dynamical localization, characterized by the suppression of the directed transport, the time dependence of the energy, and quantum scrambling. Interestingly, these suppression effects can be adjusted by the phase of the non-Hermitian kicking potential. Possible applications of our findings are discussed.

Published by the American Physical Society
2024
Increased atom-cavity coupling through cooling-induced atomic reorganization
Authors: Shu Chi , Colombo Simone , Li Zeyang , Adiyatullin Albert , Mendez Enrique , Pedrozo-Peñafiel Edwin , Vuletić Vladan
Published: September 2024

The strong coupling of atoms to optical cavities can improve optical lattice clocks as the cavity enables metrologically useful collective atomic entanglement and high-fidelity measurement. To this end, it is necessary to cool the ensemble to suppress motional broadening, and advantageous to maximize and homogenize the atom-cavity coupling. We demonstrate resolved Raman sideband cooling via the cavity as a method that can simultaneously achieve both goals. In 200 ms of Raman sideband cooling, we cool Yb171 atoms to an average vibration number 〈nx〉=0.23(7) in the tightly binding direction, resulting in 93% optical π-pulse fidelity on the clock transition S01→P03. During cooling, the atoms self-organize into locations with maximal atom-cavity coupling, which will improve quantum metrology applications.

Published by the American Physical Society
2024
Origin of anticlastic curvature in a cellular metaplate
Authors: Toyonaga Taiki , Wada Hirofumi
Published: September 2024

Generating a three-dimensional curved surface from flat sheets using simple mechanical actuation is a crucial step in developing functional shape-shifting materials. Among the methodologies relying on emergent concepts, the traditional cellular solid-based plate, with its highly porous structures, provides a versatile tool for creating doubly curved surfaces through planar bending actuation. Leveraging a combination of digital fabrication, physical experiments, finite element simulation (FES), and linear elasticity theory, we demonstrate how such a cellular metaplate can exhibit doubly curved shapes. By extending Lamb's classical theory of the anticlastic effect in thin elastic plates to our cellular metaplate, we develop a scaling law for the crossover length below which the doubly curved surface appears as bc∼bLamb/ρ, where bLamb∼Rw, with R being the externally imposed radius of curvature, w being the plate thickness, and ρ being the relative density of a given cellular geometry. The prediction is validated by our experiment and FES. The proposed framework is versatile and emphasizes the fundamental physical principles governing the mechanics of shape-morphing surfaces.

Published by the American Physical Society
2024
Simulating Quantum Computation: How Many “Bits” for “It”?
Authors: Zurel Michael , Okay Cihan , Raussendorf Robert
Published: September 2024

A recently introduced classical simulation method for universal quantum computation with magic states operates by repeated sampling from probability functions [M. Zurel PRL 260404 (2020)]. This method is closely related to sampling algorithms based on Wigner functions, with the important distinction that Wigner functions can take negative values obstructing the sampling. Indeed, negativity in Wigner functions has been identified as a precondition for a quantum speed-up. However, in the present method of classical simulation, negativity of quasiprobability functions never arises. This model remains probabilistic for all quantum computations. In this paper, we analyze the amount of classical data that the simulation procedure must track. We find that this amount is small. Specifically, for any number n of magic states, the number of bits that describe the quantum system at any given time is 2n2+O(n).

Published by the American Physical Society
2024
Mediating role of relational capital in the influence of organizational culture on international project performance for construction enterprises
Authors: Lin Yi-Hsin , Huang Zixuan , Gao Yuqing
Published: September 2024

Purpose

This study investigates the influence of market and hierarchy organizational cultures on international project performance and examines the mediating role of relational capital.

Design/methodology/approach

In-depth interviews and a cross-sectional questionnaire survey were conducted to collect primary data within international projects. Hierarchical regression analysis was used to test the hypotheses based on data collected from 62 respondents.

Findings

The results reveal that both market and hierarchy cultures affect international project performance positively. Additionally, communication, cooperation and trust help enhance project performance; however, commitment is not. This study also proves the mediating role of relational capital between organizational culture and project performance.

Research limitations/implications

This study selected only two types of organizational culture represented by Chinese construction enterprises. Future studies can explore the mediating role of relational capital between other varieties of organizational culture and project performance.

Originality/value

Given the high complexity and risks faced by projects abroad, both organizational culture, the internal environmental factor and relational capital being the external resource, are crucial for project success. This study clarifies the relationship between organizational culture, relational capital and project performance overseas. Empirical evidence to enhance international project performance for construction enterprises is provided. This study also makes contributions to international contractors who want to implement projects in developing countries.
E-work self-efficacy and innovative behaviour: a moderated mediation analysis
Authors: Dogra Prinka , Parrey Aubid Hussain
Published: September 2024

Purpose

Based on self-determination theory, the paper examines the employee’s innovative behaviour in a remote-working context. It explores the relationship between e-skill self-efficacy (ESSE) in developing innovative behaviour (IB) to stay up with the rising rate of change through the mediating mechanism of employee resilience (ER) and considering organisational support (OS) as a potential moderator in these relationships.

Design/methodology/approach

The study adopted empirical research tested on 298 remote workers from the Indian IT and Education industry. Structural Equation Modelling (SEM) via Partial Least Squares (PLS) is the statistical methodology used.

Findings

The results identified that ER partially mediates the relationship between ESSE and IB. Further, for the direct effects, it was found that ESSE directly impacts ER and IB. Intriguingly, the moderating role adds depth to our understanding of predicting nuanced conditions under which ESSE and ER influence IB.

Originality/value

Due to organisational significance, IB is gaining increasing attention from scholars. There is a dearth of knowledge on how innovative behaviour can be stimulated at the individual level, despite the rising interest of academicians. Hence, this study bridges the gap and intends to analyse the theoretical model linking ESSE and IB mediated by ER and moderated by OS conducive to the future of remote work. Further, the findings add knowledge to the literature on contemporary remote working. It aids in designing, adopting and implementing policies and practices for the organisations that have (or will move) to remote and hybrid work settings.