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We use a modified directed path algorithm to study the finite temperature chiral singularities of two color lattice QCD with staggered fermions at strong coupling. Our lattice calculations are done at a fixed finite temperature in the…

High Energy Physics - Lattice · Physics 2008-11-26 Fu-Jiun Jiang

Thermodynamical properties of nuclear matter are studied in the framework of an effective many-body field theory at finite temperature, considering the Sommerfeld approximation. We perform the calculations by using the nonlinear Boguta and…

Astrophysics · Physics 2009-11-06 Guilherme F. Marranghello , Cesar A. Z. Vasconcellos , Manfred Dillig

We introduce an updated version of our deep learning tool that predicts stellar parameters from the optical spectra of young low-mass stars with intermediate spectral resolution. We adopt a conditional invertible neural network (cINN)…

Solar and Stellar Astrophysics · Physics 2025-05-07 Da Eun Kang , Dominika Itrich , Victor F. Ksoll , Leonardo Testi , Ralf S. Klessen , Sergio Molinari

The temperature dependent effective potential (TDEP) method is generalized beyond pair interactions. The second and third order force constants are determined consistently from ab initio molecular dynamics simulations at finite temperature.…

Materials Science · Physics 2013-10-14 Olle Hellman , Igor A. Abrikosov

Brillouin microscopy has recently emerged as a new bio-imaging modality that provides information on the micromechanical properties of biological materials, cells and tissues. The data collected in a typical Brillouin microscopy experiment…

Quantitative Methods · Quantitative Biology 2024-01-11 Hadi Mahmodi , Christopher G. Poulton , Mathew N. Lesley , Glenn Oldham , Hui Xin Ong , Steven J. Langford , Irina V. Kabakova

Principal Component Analysis (PCA) is being extensively used in Astronomy but not yet exhaustively exploited for variability search. The aim of this work is to investigate the effectiveness of using the PCA as a method to search for…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 M. I. Moretti , D. Hatzidimitriou , A. Karampelas , K. V. Sokolovsky , A. Z. Bonanos , P. Gavras , M. Yang

Spectral energy distributions for models of arbitrarily rotating stars are computed using two dimensional rotating stellar models, NLTE plane parallel model atmospheres, and a code to integrate the appropriately weighted intensities over…

Astrophysics · Physics 2008-05-09 A. Gillich , R. Deupree , C. Lovekin , I. Short , N. Toque

Context. Scattering and absorption processes in stellar atmosphere affect the center-to-limb variations of the intensity (CLVI) and the linear polarization (CLVP) of stellar radiation. Aims. There are several theoretical and observational…

Solar and Stellar Astrophysics · Physics 2015-03-04 N. M. Kostogryz , S. V. Berdyugina

The Discrete Absorption Components (DACs) commonly observed in the ultraviolet lines of hot stars have previously been modelled by dynamical simulations of Corotating Interaction Regions (CIRs) in their line-driven stellar winds. Here we…

Astrophysics · Physics 2011-05-12 J. Krticka , R. K. Barrett , J. C. Brown , S. P. Owocki

Grid-based modelling is widely used for estimating stellar parameters. However, stellar model grid is sparse because of the computational cost. This paper demonstrates an application of a machine-learning algorithm using the Gaussian…

Solar and Stellar Astrophysics · Physics 2022-03-02 Tanda Li , Guy R. Davies , Alexander J. Lyttle , Warrick H. Ball , Lindsey M. Carboneau , Rafael A. Garcia

We present a new straightforward principal component analysis (PCA) method based on the diagonalization of the weighted variance-covariance matrix through two spectral decomposition methods: power iteration and Rayleigh quotient iteration.…

Instrumentation and Methods for Astrophysics · Physics 2014-12-16 Ludovic Delchambre

We analyse medium-resolution spectra (R\sim 18000) of 19 late type dwarfs in order to determine vsini-s using synthetic rather than observational template spectra. For this purpose observational data around 2.2 $\mu$m of stars with spectral…

Solar and Stellar Astrophysics · Physics 2015-06-04 Yu. Lyubchik , H. R. A. Jones , Ya. V. Pavlenko , D. J. Pinfield , K. R. Covey

This paper examines several applications of principal component analysis (PCA) to physical systems. The first of these demonstrates that the principal components in a basis of appropriate system variables can be employed to identify…

Data Analysis, Statistics and Probability · Physics 2021-02-24 David Yevick

Insights on stellar surface large-scale magnetic field topologies are usually drawn by applying Zeeman-Doppler-Imaging (ZDI) to the observed spectropolarimetric time series. However, ZDI requires experience for reliable results to be…

Solar and Stellar Astrophysics · Physics 2022-06-02 L. T. Lehmann , J. -F. Donati

We present a systematical method for obtaining analytical long-range embedded-atom potentials based on the lattice-inversion method. The potentials converge faster (exponentially) than Sutton and Chen's power-law potentials (Philos. Mag.…

Materials Science · Physics 2008-02-03 Qian Xie , Wen-Qing Zhang , Nan-xian Chen

The investigation of the pulsation properties of pre-main-sequence intermediate-mass stars is a promising tool to evaluate the intrinsic properties of these stars and to constrain current evolutionary models. Many new candidates of this…

We derive the stellar parameters of a sample of Galactic early-O type stars by analysing their UV and Far-UV spectra from FUSE (905-1187A), IUE, HST-STIS and ORFEUS (1200-2000A). The data have been modeled with spherical, hydrodynamic,…

Astrophysics · Physics 2009-11-10 Miriam Garcia , Luciana Bianchi

We consider diagonal matrix elements of local operators between multi-soliton states in finite volume in the sine-Gordon model, and formulate a conjecture regarding their finite size dependence which is valid up to corrections exponential…

High Energy Physics - Theory · Physics 2013-03-14 T. Pálmai , G. Takács

Principal component analysis (PCA) is a widely used method for dimension reduction. In high dimensional data, the "signal" eigenvalues corresponding to weak principal components (PCs) do not necessarily separate from the bulk of the "noise"…

Statistics Theory · Mathematics 2017-10-03 Edgar Dobriban

One develops a fast computational methodology for principal component analysis on manifolds. Instead of estimating intrinsic principal components on an object space with a Riemannian structure, one embeds the object space in a numerical…

Methodology · Statistics 2024-10-04 Ka Chun Wong , Vic Patrangenaru , Robert L. Paige , Mihaela Pricop Jeckstadt