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Exploring the unexpected: Disharmonized harmonic pulsation modes in high-amplitude δ Scuti stars

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arXiv 2024年

作者： Xue, Hui-Fang Niu, Jia-Shu Department of Physics Taiyuan Normal University Jinzhong030619 China Institute of Computational and Applied Physics Taiyuan Normal University Jinzhong030619 China Shanxi Key Laboratory for Intelligent Optimization Computing and Blockchain Technology Jinzhong030619 China Institute of Theoretical Physics Shanxi University Taiyuan030006 China State Key Laboratory of Quantum Optics and Quantum Optics Devices Shanxi University Taiyuan030006 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi030006 China

Harmonics are a ubiquitous feature across various pulsating stars. They are traditionally viewed as mere replicas of the independent primary pulsation modes and have thus been excluded from asteroseismological models. Recent research, however, has uncovered a significant discrepancy: in high-amplitude δ Scuti (HADS) stars, harmonics exhibit uncorrelated variations in amplitude and frequency relative to their independent primary pulsation modes. The nature of these disharmonized harmonics is a question of critical importance. In our study we analysed five triple-mode HADS stars observed by the Transiting Exoplanet Survey Satellite (TESS) and discovered some pervasive patterns of disharmonized harmonics in both the fundamental ( f0) and first overtone ( f1) pulsation modes. Intriguingly, through an in-depth frequency interaction analysis of V1393 Cen, we identified 2 f1as an independent pulsation mode, distinct from f1, and identified it as the progenitor of the frequency variations observed in 3 f1, 4 f1, 5 f1, and 6 f1. Similar behaviour can be found in DO CMi and GSC 06047-00749, in which 2 f1and 3 f1are the independent pulsation modes, respectively. Notably, we found an interesting pattern when decomposing the harmonics that might suggest a generation process of harmonics. These findings serve as a new window on the research of harmonics, which remains a hidden corner of contemporary asteroseismology. © 2024, CC BY.

关键词： Stars

Quantum Entanglement Based on Two-Photon Joint Subtraction from Two-Mode Squeezed Vacuum States

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Quantum Entanglement Based on Two-Photon Joint Subtraction f...

OptoElectronics and Communications Conference, OECC

作者： Hongbin Song Heyu Huang Hao Liu Ai Zhou Guofeng Zhang Hidehiro Yonezawa The General Education Division and Guangdong Key Laboratory of Optoelectronic Materials and Chips and Shenzhen Key Lab of Semiconductor Lasers The Chinese University of Hong Kong Shenzhen Shenzhen China School of Materials Science and Engineering and National Engineering Research Center of Fiber Optic Sensing Technology and Networks Wuhan University of Technology Wuhan China National Engineering Research Center of Fiber Optic Sensing Technology and Networks Wuhan University of Technology Wuhan China Department of Applied Mathematics The Hong Kong Polytechnic University Hongkong China Optical Quantum Control Research Team RIKEN Center for Quantum Computing Saitama Japan

We present and analyze the quantum entanglement generated from two-photon joint subtraction from two-mode squeezed vacuum states (TMSV). Larger entanglement negativity than single-photon jointly subtracted TMSV, photo... 详细信息

ISBN: (数字)9798350308396

ISBN: (纸本)9798350308402

关键词： Protocols Correlation Quantum entanglement Simulation Elementary particle vacuum Quantum networks Photonics

ComPile: A Large IR Dataset from Production Sources

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arXiv 2023年

作者： Grossman, Aiden Paehler, Ludger Parasyris, Konstantinos Ben-Nun, Tal Hegna, Jacob Moses, William S. Monsalve Diaz, Jose M. Trofin, Mircea Doerfert, Johannes University of California Davis United States School of Computation Information and Technology Technical University of Munich Germany Center for Applied Scientific Computing Lawrence Livermore National Laboratory United States University of Minnesota Twin Cities United States Department of Computer Science University of Illinois Urbana-Champaign United States Division of Mathematics and Computer Science Argonne National Laboratory United States Google Inc. United States

Code is increasingly becoming a core data modality of modern machine learning research impacting not only the way we write code with conversational agents like OpenAI’s ChatGPT, Google’s Bard, or Anthropic’s Claude, the way we translate code from one language into another, but also the compiler infrastructure underlying the language. While modeling approaches may vary and representations differ, the targeted tasks often remain the same within the individual classes of models. Yet, relying solely on the ability of modern models to extract information from unstructured code does not take advantage of 70 years of programming language and compiler development by not utilizing the structure inherent to programs in the data collection. This detracts from the performance of models working over a tokenized representation of input code and precludes the use of these models in the compiler itself. To work towards the first intermediate representation (IR) based models, we fully utilize the LLVM compiler infrastructure, shared by a number of languages, to generate a 1.4T Llama 2 token dataset of LLVM IR. We generated this dataset from programming languages built on the shared LLVM infrastructure, including Rust, Swift, Julia, and C/C++, by hooking into LLVM code generation either through the language’s package manager or the compiler directly to extract the dataset of intermediate representations from production grade programs. Statistical analysis proves the utility of our dataset not only for large language model training, but also for the introspection into the code generation process itself as well as for training of machine-learned compiler components. Copyright © 2023, The Authors. All rights reserved.

关键词： Large datasets

Non-Hermitian lattice fermions in the 2D Gross-Neveu-Yukawa model

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Physical Review D 2024年第3期110卷 034502-034502页

作者： Xingyu Guo Chen-Te Ma Hui Zhang Key Laboratory of Atomic and Subatomic Structure and Quantum Control (MOE) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter Institute of Quantum Matter South China Normal University Department of Physics and Astronomy Iowa State University Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Asia Pacific Center for Theoretical Physics Pohang University of Science and Technology School of Physics and Telecommunication Engineering South China Normal University The Laboratory for Quantum Gravity and Strings Department of Mathematics and Applied Mathematics University of Cape Town Physics Department Center for Exploration of Energy and Matter Indiana University

We work the lattice fermions and non-Hermitian formulation in the 2D Gross-Neveu-Yukawa (GNY) model and demonstrate the numerical implementation for two flavors by the hybrid Monte Carlo. Our approach has a notable advantage in dealing with chiral symmetry on a lattice by avoiding the Nielsen-Ninomiya theorem, due to the nonsymmetrized finite-difference operator. We restore the hypercubic symmetry by averaging over all possible orientations with the proper continuum limit. Our study is the first simulation for the interacting fermion formulated in a non-Hermitian way. We compare the numerical solution with the one-loop resummation. The resummation results matches with the numerical solution in ⟨ϕ⟩, ⟨ϕ2⟩, ⟨Tr(ψ¯1ψ1+ψ¯2ψ2)/2⟩, and ⟨Tr(ψ¯1ψ1+ψ¯2ψ2)ϕ/2⟩. We also used the one-loop resummation to provide the renormalization group flow and asymptotic safety in the 2D GNY model.

关键词： Nonperturbative effects in field theory Perturbation theory Chiral symmetry Hybrid Monte Carlo algorithm Lattice field theory

Building a Fault-Tolerant Quantum Computer Using Concatenated Cat Codes

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PRX Quantum 2022年第1期3卷 010329-010329页

作者： Christopher Chamberland Kyungjoo Noh Patricio Arrangoiz-Arriola Earl T. Campbell Connor T. Hann Joseph Iverson Harald Putterman Thomas C. Bohdanowicz Steven T. Flammia Andrew Keller Gil Refael John Preskill Liang Jiang Amir H. Safavi-Naeini Oskar Painter Fernando G.S.L. Brandão AWS Center for Quantum Computing Pasadena California 91125 USA IQIM California Institute of Technology Pasadena California 91125 USA Department of Physics Yale University New Haven Connecticut 06511 USA Pritzker School of Molecular Engineering The University of Chicago Illinois 60637 USA Department of Applied Physics and Ginzton Laboratory Stanford University Stanford California 94305 USA

We present a comprehensive architectural analysis for a proposed fault-tolerant quantum computer based on cat codes concatenated with outer quantum error-correcting codes. For the physical hardware, we propose a system of acoustic resonators coupled to superconducting circuits with a two-dimensional layout. Using estimated physical parameters for the hardware, we perform a detailed error analysis of measurements and gates, including cnot and Toffoli gates. Having built a realistic noise model, we numerically simulate quantum error correction when the outer code is either a repetition code or a thin rectangular surface code. Our next step toward universal fault-tolerant quantum computation is a protocol for fault-tolerant Toffoli magic state preparation that significantly improves upon the fidelity of physical Toffoli gates at very low qubit cost. To achieve even lower overheads, we devise a new magic state distillation protocol for Toffoli states. Combining these results together, we obtain realistic full-resource estimates of the physical error rates and overheads needed to run useful fault-tolerant quantum algorithms. We find that with around 1000 superconducting circuit components, one could construct a fault-tolerant quantum computer that can run circuits, which are currently intractable for classical computers. Hardware with 18 000 superconducting circuit components, in turn, could simulate the Hubbard model in a regime beyond the reach of classical computing.

关键词： Quantum algorithms Quantum benchmarking Quantum error correction Quantum gates Surface code quantum computing Topological quantum computing

High-fidelity parallel entangling gates on a neutral atom quantum computer

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arXiv 2023年

作者： Evered, Simon J. Bluvstein, Dolev Kalinowski, Marcin Ebadi, Sepehr Manovitz, Tom Zhou, Hengyun Li, Sophie H. Geim, Alexandra A. Wang, Tout T. Maskara, Nishad Levine, Harry Semeghini, Giulia Greiner, Markus Vuletić, Vladan Lukin, Mikhail D. Department of Physics Harvard University CambridgeMA02138 United States QuEra Computing Inc. BostonMA02135 United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States Department of Physics Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States

The ability to perform entangling quantum operations with low error rates in a scalable fashion is a central element of useful quantum information processing [1]. Neutral atom arrays have recently emerged as a promising quantum computing platform, featuring coherent control over hundreds of qubits [2, 3] and any-to-any gate connectivity in a flexible, dynamically reconfigurable architecture [4]. The major outstanding challenge has been to reduce errors in entangling operations mediated through Rydberg interactions [5]. Here we report the realization of two-qubit entangling gates with 99.5% fidelity on up to 60 atoms in parallel, surpassing the surface code threshold for error correction [6, 7]. Our method employs fast single-pulse gates based on optimal control [8], atomic dark states to reduce scattering [9], and improvements to Rydberg excitation and atom cooling [10]. We benchmark fidelity using several methods based on repeated gate applications [11, 12], characterize the physical error sources, and outline future improvements. Finally, we generalize our method to design entangling gates involving a higher number of qubits, which we demonstrate by realizing low-error three-qubit gates [13, 14]. By enabling high-fidelity operation in a scalable, highly connected system, these advances lay the groundwork for large-scale implementation of quantum algorithms [15], error-corrected circuits [7], and digital simulations [16]. Copyright © 2023, The Authors. All rights reserved.

关键词： Error correction

Rectangular multiple-relaxation-time lattice Boltzmann method for the Navier-Stokes and nonlinear convection-diffusion equations: General equilibrium and some important issues

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arXiv 2022年

作者： Chai, Zhenhua Yuan, Xiaolei Shi, Baochang Institute of Interdisciplinary Research for Mathematics and Applied Science School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Wuhan430074 China College of Mathematics and Information Science Hebei University Baoding071002 China

In this paper, we develop a general rectangular multiple-relaxation-time lattice Boltzmann (RMRT-LB) method for the Navier-Stokes equations (NSEs) and nonlinear convection-diffusion equation (NCDE) by extending our recent unified framework of MRT-LB method [Z.H. Chai and B.C. Shi, Phys. Rev. E 102, 023306 (2020)], where a rectangular equilibrium distribution function (REDF) [J.H. Lu et al, Phil. Trans. R. Soc. A 369, 2311-2319 (2011)] on a rectangular lattice is utilized. Due to the anisotropy of discrete velocities on a rectangular lattice, the third-order moment of REDF is inconsistent with that of popular LB method, and thus the previous unified framework of MRT-LB method cannot be directly applied to the NSEs using the REDF on the rectangular rDdQq (q discrete velocities in d-dimensional space, d ≥ 1) lattice. The macroscopic NSEs can be recovered from the RMRT-LB method through the direct Taylor expansion method by properly selecting the relaxation sub-matrix S2 which is related to kinetic viscosity and bulk viscosity. While the rectangular lattice does not lead to the change of the zero-th, first and second-order moments of REDF, thus the unified framework of MRT-LB method can be directly applied to the NCDE. It should be noted that the RMRT-LB model for NSEs can be derived on the rDdQq lattice, including rD2Q9, rD3Q19, and rD3Q27 lattices, while there are no rectangular D3Q13 and D3Q15 lattices within this framework of RMRT-LB method. Thanks to the block-lower triangular-relaxation matrix introduced in the unified framework, the RMRT-LB versions (if existed) of the previous MRT-LB models can be obtained, including those based on raw (natural)-moment, central-moment, Hermite-moment, and central Hermite-moment, respectively. It is also found that when the standard or regular lattice is used, and the sound speed is taken as an adjustable parameter, the present RMRT-LB method becomes a new class of MRT-LB method for the NSEs and NCDE, and the commonly used MRT-LB

关键词： Navier Stokes equations

Quantum entanglement between optical and microwave photonic qubits

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arXiv 2023年

作者： Meesala, Srujan Lake, David Wood, Steven Chiappina, Piero Zhong, Changchun Beyer, Andrew D. Shaw, Matthew D. Jiang, Liang Painter, Oskar Kavli Nanoscience Institute and Thomas J. Watson Sr. Laboratory of Applied Physics California Institute of Technology PasadenaCA91125 United States Institute for Quantum Information and Matter California Institute of Technology PasadenaCA91125 United States Pritzker School of Molecular Engineering The University of Chicago ChicagoIL60637 United States Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Dr PasadenaCA91109 United States Center for Quantum Computing Amazon Web Services PasadenaCA91125 United States

Entanglement is an extraordinary feature of quantum mechanics. Sources of entangled optical photons were essential to test the foundations of quantum physics through violations of Bell’s inequalities. More recently, entangled many-body states have been realized via strong non-linear interactions in microwave circuits with superconducting qubits. Here we demonstrate a chip-scale source of entangled optical and microwave photonic qubits. Our device platform integrates a piezo-optomechanical transducer with a superconducting resonator which is robust under optical illumination. We drive a photon-pair generation process and employ a dual-rail encoding intrinsic to our system to prepare entangled states of microwave and optical photons. We place a lower bound on the fidelity of the entangled state by measuring microwave and optical photons in two orthogonal bases. This entanglement source can directly interface telecom wavelength time-bin qubits and GHz frequency superconducting qubits, two well-established platforms for quantum communication and computation, respectively. Copyright © 2023, The Authors. All rights reserved.

关键词： Quantum entanglement

Ultra-compact nonvolatile phase shifter based on electrically reprogrammable transparent phase change materials

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PhotoniX 2022年第1期3卷 74-86页

作者： Carlos Rios Qingyang Du Yifei Zhang Cosmin-Constantin Popescu Mikhail Y.Shalaginov Paul Miller Christopher Roberts Myungkoo Kang Kathleen A.Richardson Tian Gu Steven A.Vitale Juejun Hu Department of Materials Science&Engineering University of MarylandCollege ParkMDUSA Institute for Research in Electronics and Applied Physics University of MarylandCollege ParkMDUSA Research Center for Intelligent Optoelectronic Computing Zhejiang Lab311121 HangzhouChina Department of Materials Science&Engineering Massachusetts Institute of TechnologyCambridgeMAUSA Lincoln Laboratory Massachusetts Institute of TechnologyLexingtonMAUSA The College of Optics&Photonics CREOLUniversity of Central FloridaOrlandoFLUSA Department of Materials Science and Engineering University of Central FloridaOrlandoFLUSA Materials Research Laboratory Massachusetts Institute of TechnologyCambridgeMAUSA

Optical phase shifters constitute the fundamental building blocks that enableprogrammable photonic integrated circuits (PICs)—the cornerstone of on-chipclassical and quantum optical technologies [1, 2]. Thus far, carrier modulation andthermo-optical effect are the chosen phenomena for ultrafast and low-loss phaseshifters, respectively;however, the state and information they carry are lost once thepower is turned off—they are volatile. The volatility not only compromises energyefficiency due to their demand for constant power supply, but also precludes themfrom emerging applications such as in-memory computing. To circumvent thislimitation, we introduce a phase shifting mechanism that exploits the nonvolatilerefractive index modulation upon structural phase transition of Sb2Se3, a bi-statetransparent phase change material (PCM). A zero-static power and electrically-drivenphase shifter is realized on a CMOS-backend silicon-on-insulator platform, featuringrecord phase modulation up to 0.09 π/μm and a low insertion loss of 0.3 dB/π, whichcan be further improved upon streamlined design. Furthermore, we demonstratephase and extinction ratio trimming of ring resonators and pioneer a one-step partialamorphization scheme to enhance speed and energy efficiency of PCM devices. Adiverse cohort of programmable photonic devices is demonstrated based on theultra-compact PCM phase shifter.

关键词： phase transparent nonvolatile