arXiv subjects

Lu Cao

Publications and source records attributed to Lu Cao.

At least 37 records · Page 2Linked to original sources

arXiv2024

Modeling iPSC-derived Endothelial Cell Transition in Tumor Angiogenesis using Petri Nets

Tumor angiogenesis concerns the development of new blood vessels supplying the necessary nutrients for the further development of existing tumor cells. The entire process is complex, involving the production and consumption of chemicals, endothelial cell transitions as well as cell interactions, divisions, and migrations. Microfluidic cell culture platform has been used to study angiogenesis of endothelial cells derived from human induced pluripotent stem cells (iPSC-ECs) for a physiological relevant micro-environment. In this paper, we elaborate on how to define a pipeline for simulating the transformation and process that an iPSC-derived endothelial cell goes through in this biological scenario. We leverage the robustness and simplicity of Petri nets for modeling the cell transformation and associated constraints. The environmental and spacial factors are added using custom 2-dimensional grids. Although the pipeline does not capture the entire complexity of tumor angiogenesis, we are able to capture the essence of endothelial cell transitions in tumor angiogenesis using this conceptually simplified solution.

q-bio.CB↗

arXiv2024

Visualizing, Analyzing and Constructing L-System from Arborized 3D Model Using a Web Application

In biology, arborized structures are well represented and typically complex for visualization and analysis. In order to have a profound understanding of the topology of arborized 3D biological model, higher level abstraction is needed. We aim at constructing an abstraction of arborized 3D biological model to an L-system that provides a generalized formalization in a grammar to represent complex structures. The focus of this paper is to combine 3D visualization, analysis and L-system abstraction into a single web application. We designed a front-end user interface and a back-end. In the front-end, we used A-Frame and defined algorithms to generate and visualize L-systems. In the back-end, we utilized the Vascular Modelling Toolkit's (VMTK) centerline analysis methods to extract important features from the arborized 3D models, which can be applied to L-system generation. In addition, two 3D biological models: lactiferous duct and artery are used as two case studies to verify the functionality of this web application. In conclusion, our web application is able to visualize, analyse and create L-system abstractions of arborized 3D models. This in turn provides workflow-improving benefits, easy accessibility and extensibility.

q-bio.TO↗

arXiv2023

Measurements of $|V_{cb}|$ and $|V_{ub}|$ from Belle and Belle II

This proceeding summarizes recent measurements of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements $|V_{cb}|$ and $|V_{ub}|$ at the Belle and Belle~II experiments. It provides insights derived from both exclusive and inclusive determinations. Preliminary results from Belle~II are discussed, focusing on $B^0\to D^{*-}\ell^+ ν$ and $B^{0} \to π^{-} \ell^{+} ν$ utilizing $189 \, \mathrm{fb}^{-1}$ data collected at the $Υ(4S)$ resonance. This reveals the derived branching fractions and $|V_{xb}|$. The shape measurement of $B \to D^{*} \ell ν$ at Belle extracted $|V_{cb}|$ employing new lattice-QCD calculations as input and provided additional tests on the universality of light lepton flavors. In the realm of inclusive decay, the measurement for $|V_{ub}|$ and the differential spectra of $B \to X_{u} \ell ν$ decays have been performed. This presentation also encapsulates the new analyses of $|V_{ub}|^{\mathrm{excl}}/|V_{ub}|^{\mathrm{incl}}$ and $|V_{ub}|^{\mathrm{incl}}/|V_{cb}|^{\mathrm{incl}}$ ratios.

hep-ex↗

arXiv2023

New results on $|V_{ub}|$ using inclusive and exclusive $B$ decays from the Belle experiment

We present two recent measurements of semileptonic B decays at Belle, offering valuable insights into the determination of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $|V_{ub}|$. These analyses use the full Belle dataset, comprising $772 \times 10^6$ $B\bar{B}$ pairs collected at the $Υ(4S)$ resonance. With an innovative strategy, the inclusive $B \to X_u \ell ν$ and exclusive $B \to π\ell ν$ decays are simultaneously analyzed for the first time, and the $|V_{ub}|$ ratio is extracted as $|V_{ub}^{\mathrm{excl.}}|/|V_{ub}^{\mathrm {incl.}}|=0.97 \pm 0.12$. Furthermore, we provide preliminary results for the inclusive branching fractions ratio of $B \to X_u \ell ν$ and $B \to X_c \ell ν$ decays, accompanied by additional interpretations aimed at deriving the inclusive $|V_{ub}|/|V_{cb}|$ ratio.

hep-ex↗

arXiv2023

SGED: A Benchmark dataset for Performance Evaluation of Spiking Gesture Emotion Recognition

In the field of affective computing, researchers in the community have promoted the performance of models and algorithms by using the complementarity of multimodal information. However, the emergence of more and more modal information makes the development of datasets unable to keep up with the progress of existing modal sensing equipment. Collecting and studying multimodal data is a complex and significant work. In order to supplement the challenge of partial missing of community data. We collected and labeled a new homogeneous multimodal gesture emotion recognition dataset based on the analysis of the existing data sets. This data set complements the defects of homogeneous multimodal data and provides a new research direction for emotion recognition. Moreover, we propose a pseudo dual-flow network based on this dataset, and verify the application potential of this dataset in the affective computing community. The experimental results demonstrate that it is feasible to use the traditional visual information and spiking visual information based on homogeneous multimodal data for visual emotion recognition.The dataset is available at \url{https://github.com/201528014227051/SGED}

cs.CV↗

arXiv2023

A Fast Feature Point Matching Algorithm Based on IMU Sensor

In simultaneous localization and mapping (SLAM), image feature point matching process consume a lot of time. The capacity of low-power systems such as embedded systems is almost limited. It is difficult to ensure the timely processing of each image information. To reduce time consuming when matching feature points in SLAM, an algorithm of using inertial measurement unit (IMU) to optimize the efficiency of image feature point matching is proposed. When matching two image feature points, the presented algorithm does not need to traverse the whole image for matching feature points, just around the predicted point within a small range traversal search to find matching feature points. After compared with the traditional algorithm, the experimental results show that this method has greatly reduced the consumption of image feature points matching time. All the conclusions will help research how to use the IMU optimize the efficiency of image feature point matching and improve the real-time performance in SLAM.

cs.CV↗

arXiv2022

Tunable vortex Majorana modes controlled by strain in homogeneous LiFeAs

The iron-based superconductors (FeSCs) have recently emerged as a promising single-material Majorana platform by hosting isolated Majorana zero modes (MZMs) at relatively high temperatures. To further verify its Majorana nature and move forward to build topological quantum qubit, it is highly desirable to achieve tunability for MZMs on homogeneous FeSCs. Here, with an in-situ strain device, we can controllably create MZMs on the homogeneous surface of stoichiometric superconductor LiFeAs by inducing a topological phase transition. The evolution of discrete energy modes inside a strained vortex is found to mimics exactly as the predicted topological vortex case, proving the Majorana nature of emerging zero modes of vortex. Such tunability of MZMs in a homogeneous superconductor is an important step toward their application in topological quantum computation.

cond-mat.supr-con↗

arXiv2022

Snowmass White Paper: Belle II physics reach and plans for the next decade and beyond

Belle II is an experiment operating at the intensity frontier. Over the next decades, it will record the decay of billions of bottom mesons, charm hadrons, and tau leptons produced in 10 GeV electron-positron collisions at the SuperKEKB high-luminosity collider at KEK. These data, collected in low-background and kinematically known conditions, will allow us to measure hundreds of parameters that test the standard model (SM) and probe for the existence of new particles, at mass scales orders of magnitudes higher than those studied at the energy frontier. We project our sensitivities for measurements that are of primary relevance and where Belle II will be unique or world leading for data corresponding to 1 to 50 ab$^{-1}$. Belle II will uniquely probe non-SM contributions in sensitive $b \to q\bar q s$ decays and charmless $b \to q\bar q d(u)$ decays, semileptonic $b \to s ν\barν$ and $s τ^+ τ^-$ decays, fully leptonic $b \to \ell ν$ decays, and select $c \to u$ processes. Belle II will lead exploration of non-SM physics in $b \to c τν$ and $b \to s γ$ decays and will most precisely determine the quark-mixing parameters $|V_{ub}|$ and $|V_{cb}|$. Belle II will measure many parameters in $τ$ physics to precisions that will be world leading for the foreseeable future, including the electric and magnetic dipole moments, branching fractions for charged-lepton-flavor-violating decays, and quantities that test lepton-flavor universality. Belle II will perform unique searches for dark-sector particles with masses in the MeV-GeV range. We will also pursue a broad spectroscopy program for conventional and multiquark $c \bar c$ and $b \bar b$ states and provide essential inputs to sharpen the interpretation of muon magnetic-anomaly results. Our exploration of uncharted regions of non-SM parameter space with high precision will reveal non-SM particles or set stringent constraints on their existence, guiding future endeavors.

hep-ex↗

arXiv2022

Ordered and tunable Majorana-zero-mode lattice in naturally strained LiFeAs

Majorana zero modes (MZMs) obey non-Abelian statistics and are considered building blocks for constructing topological qubits. Iron-based superconductors with topological band structures have emerged as promising hosting materials, since isolated candidate MZMs in the quantum limit have been observed inside the topological vortex cores. However, these materials suffer from issues related to alloying-induced disorder, uncontrolled vortex lattices and a low yield of topological vortices. Here, we report the formation of an ordered and tunable MZM lattice in naturally-strained stoichiometric LiFeAs by scanning tunneling microscopy/spectroscopy (STM/S). We observe biaxial charge density wave (CDW) stripes along the Fe-Fe and As-As directions in the strained regions. The vortices are pinned on the CDW stripes in the As-As direction and form an ordered lattice. We detect more than 90 percent of the vortices to be topological and possess the characteristics of isolated MZMs at the vortex center, forming an ordered MZM lattice with the density and the geometry tunable by an external magnetic field. Remarkably, with decreasing the spacing of neighboring vortices, the MZMs start to couple with each other. Our findings provide a new pathway towards tunable and ordered MZM lattices as a platform for future topological quantum computation.

cond-mat.supr-con↗

arXiv2022

Defending against Co-residence Attack in Energy-Efficient Cloud: An Optimization based Real-time Secure VM Allocation Strategy

Resource sharing among users serves as the foundation of cloud computing, which, however, may also cause vulnerabilities to diverse co-residence attacks launched by malicious virtual machines (VM) residing in the same physical server with the victim VMs. In this paper, we aim to defend against such co-residence attacks through a secure, workload-balanced, and energy-efficient VM allocation strategy. Specifically, we model the problem as an optimization problem by quantifying and minimizing three key factors: (1) the security risks, (2) the power consumption and (3) the unbalanced workloads among different physical servers. Furthermore, this work considers a realistic environmental setting by assuming a random number of VMs from different users arriving at random timings, which requires the optimization solution to be continuously evolving. As the optimization problem is NP-hard, we propose to first cluster VMs in time windows, and further adopt the Ant Colony Optimization (ACO) algorithm to identify the optimal allocation strategy for each time window. Comprehensive experimental results based on real world cloud traces validates the effectiveness of the proposed scheme.

cs.DC↗

arXiv2021

New results on semileptonic $B$ decays from the Belle experiment

This proceeding summarizes the recent measurements of semileptonic $b\to u$ decays from the Belle experiment. These analyses use the full data set collected at the $Υ(4S)$ resonance at KEKB accelerator complex with a center-of-mass energy of $\sqrt{s} = 10.58$ GeV, which contains an integrated luminosity of 711 fb$^{-1}$ and corresponds to 772 million $Υ(4S) \to B\bar{B}$ events. In the sector of inclusive decay, the partial branching fraction of $B \to X_{u} \ell ν$ decays and the CKM matrix element $|V_{ub}|$ are measured with hadronic tagging. The first measurement of differential branching fractions of $B \to X_{u} \ell ν$ are shown as a function of different kinematic variables in this contribution as a preliminary result. For the exclusive mode, the branching fraction of $B^{+} \to π^{+}π^{-} \ell ν$ including both resonant and non-resonant contributions is measured for the first time. The preliminary results on the branching fractions of $B^{+} \to η\ell ν$ and $B^{+} \to η^{(\prime)} \ell ν$ in the full $q^{2}$ range are also presented.

hep-ex↗

arXiv2021

Energy Recovery Linac Based Fully Coherent Light Source

Energy recovery linac (ERL) holds great promise for generating high repetition-rate and high brightness electron beams. The application of ERL to drive a free-electron laser is currently limited by its low peak current. In this paper, we consider the combination of ERL with the recently proposed angler-dispersion induced microbunching technique to generate fully coherent radiation pulses with high average brightness and tunable pulse length. Start-to-end simulations have been performed based on a low energy ERL (600 MeV) for generating coherent EUV radiation pulses. The results indicate an average brightness over 10^25 phs/s/mm2/mrad2/0.1%BW and average power of about 100 W at 13.5 nm or 20 W with the spectral resolution of about 0.5 meV with the proposed technique. Further extension of the proposed scheme to shorter wavelength based on an ERL complex is also discussed.

physics.acc-ph↗

arXiv2021

Common ($π$,$π$) Band Folding and Surface Reconstruction in FeAs-Based Superconductors

High resolution angle-resolved photoemission spectroscopy (ARPES) measurements are carried out on CaKFe$_4$As$_4$, KCa$_2$Fe$_4$As$_4$F$_2$ and (Ba$_{0.6}$K$_{0.4}$)Fe$_2$As$_2$ superconductors. Clear evidence of band folding between the Brillouin zone center and corners with a ($π$,$π$) wave vector has been found from the measured Fermi surface and band structures in all the three kinds of superconductors. A dominant $\sqrt{2}\,\times\,\sqrt{2}$ surface reconstruction is observed on the cleaved surface of CaKFe$_4$As$_4$ by scanning tunneling microscopy (STM) measurements. We propose that the commonly observed $\sqrt{2}\,\times\,\sqrt{2}$ reconstruction in the FeAs-based superconductors provides a general scenario to understand the origin of the ($π$,$π$) band folding. Our observations provide new insights in understanding the electronic structure and superconductivity mechanism in iron-based superconductors.

cond-mat.supr-con↗

arXiv2021

Two distinct superconducting states controlled by orientation of local wrinkles in LiFeAs

We observe two types of superconducting states controlled by orientations of local wrinkles on the surface of LiFeAs. Using scanning tunneling microscopy/spectroscopy, we find type-I wrinkles enlarge the superconducting gaps and enhance the transition temperature, whereas type-II wrinkles significantly suppress the superconducting gaps. The vortices on wrinkles show a C2 symmetry, indicating the strain effects on the wrinkles. A discontinuous switch of superconductivity occurs at the border between two different wrinkles. Our results demonstrate that the local strain effect could affect superconducting order parameter of LiFeAs with a possible Lifshitz transition, by alternating crystal structure in different directions.

cond-mat.supr-con↗

arXiv2021

Mimicing the Kane-Mele type spin orbit interaction by spin-flexual phonon coupling in graphene devices

On the efforts of enhancing the spin orbit interaction (SOI) of graphene for seeking the dissipationless quantum spin Hall devices, unique Kane-Mele type SOI and high mobility samples are desired. However, common external decoration often introduces extrinsic Rashba-type SOI and simultaneous impurity scattering. Here we show, by the EDTA-Dy molecule decorating, the Kane-Mele type SOI is mimicked with even improved carrier mobility. It is evidenced by the suppressed weak localization at equal carrier densities and simultaneous Elliot-Yafet spin relaxation. The extracted spin scattering time is monotonically dependent on the carrier elastic scattering time, where the Elliot-Yafet plot gives the interaction strength of 3.3 meV. Improved quantum Hall plateaus can be even seen after the external operation. This is attributed to the spin-flexural phonon coupling induced by the enhanced graphene ripples, as revealed by the in-plane magnetotransport measurement.

cond-mat.mes-hall↗

arXiv2021

New results on inclusive $B\to X_{u} \ell ν$ decay from the Belle experiment

We report on the measurement of inclusive charmless semileptonic B decays $B \to X_{u} \ell ν$. The analysis makes use of hadronic tagging and is performed on the full data set of the Belle experiment comprising 772 million $B\bar{B}$ pairs. In the proceedings, the preliminary results of measurements of partial branching fractions and the CKM matrix element $|V_{ub}|$ are presented.

hep-ex↗

arXiv2020

Analysis of $B_c \to τν_τ$ at CEPC

The precise determination of the $B_c \to τν_τ$ branching ratio provides an advantageous opportunity for understanding the electroweak structure of the Standard Model, measuring the CKM matrix element $|V_{cb}|$ and probing new physics models. In this paper, we discuss the potential of measuring the processes of $B_c \to τν_τ$ with $τ$ decaying leptonically at the proposed Circular Electron Positron Collider (CEPC). We conclude that during the $Z$ pole operation, the channel signal can achieve five $σ$ significance with $\sim 10^9$ $Z$ decays, and the signal strength accuracies for $B_c \to τν_τ$ can reach around 1% level at the nominal CEPC $Z$ pole statistics of one trillion $Z$ decays assuming the total $B_c \to τν_τ$ yield is $3.6 \times 10^6$. Our theoretical analysis indicates the accuracy could provide a strong constraint on the general effective Hamiltonian for the $b \to cτν$ transition. If the total $B_c$ yield can be determined to $\mathcal{O}(1\%)$ level of accuracy in the future, these results also imply $|V_{cb}|$ could be measured up to $\mathcal{O}(1\%)$ level of accuracy.

hep-ex↗

arXiv2020

Tunable vortex Majorana zero modes in LiFeAs superconductor

The recent realization of pristine Majorana zero modes (MZMs) in vortices of iron-based superconductors (FeSCs) provides a promising platform for long-sought-after fault-tolerant quantum computation. A large topological gap between the MZMs and the lowest excitations enabled detailed characterization of vortex MZMs in those materials. Despite those achievements, a practical implementation of topological quantum computation based on MZM braiding remains elusive in this new Majorana platform. Among the most pressing issues are the lack of controllable tuning methods for vortex MZMs and inhomogeneity of the FeSC Majorana compounds that destroys MZMs during the braiding process. Thus, the realization of tunable vortex MZMs in a truly homogeneous compound of stoichiometric composition and with a charge neutral cleavage surface is highly desirable. Here we demonstrate experimentally that the stoichiometric superconductor LiFeAs is a good candidate to overcome these two obstacles. Using scanning tunneling microscopy, we discover that the MZMs, which are absent on the natural surface, can appear in vortices influenced by native impurities. Our detailed analysis and model calculations clarify the mechanism of emergence of MZMs in this material, paving a way towards MZMs tunable by controllable methods such as electrostatic gating. The tunability of MZMs in this homogeneous material offers an unprecedented platform to manipulate and braid MZMs, the essential ingredients for topological quantum computation.

cond-mat.supr-con↗