Standard statistical analysis is unable to provide reliable confidence intervals on expectation values of probability distributions that do not satisfy the conditions of the central limit theorem. We present a regression-based estimator of an arbitrary moment of a probability distribution with power-law heavy tails that exploits knowledge of the exponents of its asymptotic decay to bypass this issue entirely. Our method is applied to synthetic data and to energy and atomic force data from variational and diffusion quantum Monte Carlo calculations, whose distributions have known asymptotic forms [J. R. Trail, Phys. Rev. E 77, 016703 (2008)PLEEE81539-375510.1103/PhysRevE.77.016703; A. Badinski et al., J. Phys.: Condens. Matter 22, 074202 (2010)JCOMEL0953-898410.1088/0953-8984/22/7/074202]. We obtain convergent, accurate confidence intervals on the variance of the local energy of an electron gas and on the Hellmann-Feynman force on an atom in the all-electron carbon dimer. In each of these cases the uncertainty on our estimator is 45% and 60 times smaller, respectively, than the nominal (ill-defined) standard error.
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http://dx.doi.org/10.1103/PhysRevE.99.063312 | DOI Listing |
ACS Omega
January 2025
Department of Applied Chemistry, Faculty of Applied Sciences Ait Melloul, Ibn Zohr University, Agadir 60000, Morocco.
The objective of the study was to synthesize tetrazole molecules featuring nitro groups positioned at the para and meta locations. We aimed to assess their effectiveness in inhibiting corrosion of mild steel in a 1 M HCl solution at 298 K. Tetrazoles with 2,5-disubstitution were created using [3 + 2] cycloaddition and N-alkylation techniques, with a particular emphasis on synthesizing molecules that contain nitro groups.
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January 2025
Instituto de Física, Universidade Federal de Goiás, Goiânia, Goiás 74001-970, Brazil.
We investigate the energetic and structural properties of small lithium clusters doped with a carbon atom using a combination of computational methods, including density functional theory (DFT), diffusion quantum Monte Carlo (DMC), and the Hartree-Fock (HF) approximation. We calculate the lowest energy structures, total ground-state energies, electron populations, binding energies, and dissociation energies as a function of cluster size. Our results show that carbon doping significantly enhances the stability of lithium clusters, increasing the magnitude of the binding energy by 0.
View Article and Find Full Text PDFPhotodiagnosis Photodyn Ther
January 2025
Maebashi-Institute of Technology, Systems Life Engineering, Gunma, 371-0816 Japan. Electronic address:
Introduction: The successful diagnosis and treatment of early-stage breast cancer enhances the quality of life of patients. As a promising alternative to recently developed magnetic resonance imaging-guided radiotherapy, we proposed fluorescence molecular imaging-guided photodynamic therapy (FMI-guided PDT), which requires no expensive equipment. In the FMI simulations, ICG-C11 which has emission peaks at near-infrared wavelengths was used as the FMI agent.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1X6, Canada.
Monte Carlo (MC) simulations have become important in advancing nanoparticle (NP)-based applications for cancer imaging and therapy. This review explores the critical role of MC simulations in modeling complex biological interactions, optimizing NP designs, and enhancing the precision of therapeutic and diagnostic strategies. Key findings highlight the ability of MC simulations to predict NP bio-distribution, radiation dosimetry, and treatment efficacy, providing a robust framework for addressing the stochastic nature of biological systems.
View Article and Find Full Text PDFEntropy (Basel)
December 2024
Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso 2390123, Chile.
In this work, we study the magnetocaloric effect (MCE) in a working substance corresponding to a square lattice of spins with possible orientations, known as the "-state clock model". When the -state clock model has Q≥5 possible configurations, it presents the famous Berezinskii-Kosterlitz-Thouless (BKT) phase associated with vortex states. We calculate the thermodynamic quantities using Monte Carlo simulations for even numbers, ranging from Q=2 to Q=8 spin orientations per site in a lattice.
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