arXiv subjects

Evgeny Posenitskiy

Publications and source records attributed to Evgeny Posenitskiy.

5 recordsLinked to original sources

arXiv2025

QMCkl: A Kernel Library for Quantum Monte Carlo Applications

Quantum Monte Carlo (QMC) methods deliver highly accurate electronic structure calculations but are computationally intensive. The quantum Monte Carlo kernel library (QMCkl) provides a modular, portable collection of high-performance kernels implementing the core building blocks of QMC calculations. It offers a C-compatible API, supports the TREXIO standard for input, and covers essential QMC kernels including atomic and molecular orbitals, cusp corrections, Jastrow factor, and the necessary derivatives also to perform variational and structural optimization. QMCkl separates algorithmic development from hardware-specific tuning by combining human-readable reference implementations with performance-optimized kernels that produce identical numerical results. The library enables consistent, efficient, and reproducible simulations across different QMC codes and architectures, and achieves substantial speedups in the evaluation of the energy and its derivatives. Beyond QMC, QMCkl can accelerate deterministic quantum chemistry workflows and visualization tools, promoting cross-code interoperability and simplifying high-performance scientific software development.

physics.chem-ph↗

arXiv2025

Pushing the Accuracy Limit of Foundation Neural Network Models with Quantum Monte Carlo Forces and Path Integrals

We propose an end-to-end integrated strategy to produce highly accurate quantum chemistry (QC) synthetic datasets (energies and forces) aimed at deriving Foundation Machine Learning models for molecular simulation. Starting from Density Functional Theory (DFT), a "Jacob's Ladder" approach leverages computationally-optimized layers of massively GPU-accelerated software with increasing accuracy. Thanks to Exascale, this is the first time that the computationally intensive calculation of Quantum Monte Carlo forces (QMC), and the combination of multi-determinant QMC energies and forces with selected-Configuration Interaction wavefunctions, are computed at such scale at the complete basis-set limit. To bridge the gap between accurate QC and condensed-phase Molecular Dynamics, we leverage transfer learning to improve the DFT-based FeNNix-Bio1 foundation model. The resulting approach is coupled to path integrals adaptive sampling quantum dynamics to perform nanosecond reactive simulations at unprecedented accuracy. These results demonstrate the promise of Exascale to deepen our understanding of the inner machinery of complex biosystems.

physics.chem-ph↗

arXiv2024

Shortcut to Chemically Accurate Quantum Computing via Density-based Basis-set Correction

Using GPU-accelerated state-vector emulation, we propose to embed a quantum computing ansatz into density-functional theory via density-based basis-set corrections (DBBSC) to obtain quantitative quantum-chemistry results on molecules that would otherwise require brute-force quantum calculations using hundreds of logical qubits. Indeed, accessing a quantitative description of chemical systems while minimizing quantum resources is an essential challenge given the limited qubit capabilities of current quantum processors. We provide a shortcut towards chemically accurate quantum computations by approaching the complete-basis-set limit through coupling the DBBSC approach, applied to any given variational ansatz, to an on-the-fly crafting of basis sets specifically adapted to a given system and user-defined qubit budget. The resulting approach self-consistently accelerates the basis-set convergence, improving electronic densities, ground-state energies, and first-order properties (e.g. dipole moments), but can also serve as a classical, a posteriori, energy correction to quantum hardware calculations with expected applications in drug design and materials science.

physics.chem-ph↗

arXiv2023

TREXIO: A File Format and Library for Quantum Chemistry

TREXIO is an open-source file format and library developed for the storage and manipulation of data produced by quantum chemistry calculations. It is designed with the goal of providing a reliable and efficient method of storing and exchanging wave function parameters and matrix elements, making it an important tool for researchers in the field of quantum chemistry. In this work, we present an overview of the TREXIO file format and library. The library consists of a front-end implemented in the C programming language and two different back-ends: a text back-end and a binary back-end utilizing the HDF5 library which enables fast read and write operations. It is compatible with a variety of platforms and has interfaces for the Fortran, Python, and OCaml programming languages. In addition, a suite of tools has been developed to facilitate the use of the TREXIO format and library, including converters for popular quantum chemistry codes and utilities for validating and manipulating data stored in TREXIO files. The simplicity, versatility, and ease of use of TREXIO make it a valuable resource for researchers working with quantum chemistry data.

physics.chem-ph↗

arXiv2021

Hydrogenation of C$_{24}$ carbon clusters : structural diversity and energetic properties

This work aims at exploring the potential energy surfaces of C$_{24}$H$_n${n=0,6,12,18,24} up to 20-25\,eV using the genetic algorithm in combination with the density functional based tight binding (DFTB) potential. The structural diversity of the non fragmented structures was analysed using order parameters which were chosen as the number of 5 or 6 carbon rings and the asphericity constant $β$. The most abundant and lowest energy population was found to correspond to a flakes population, constituted of isomers of variable shapes possessing a large number of 5 or 6-carbon rings. This population is characterized by a larger number of spherical isomers when $n_H/n_C$ increases. Simultaneously, the fraction of the pretzels population constituted of spherical isomers possessing fewer 5 or 6 carbon ring cycles increases. For all hydrogenation rates, the fraction of cages population remains extremely minor while the branched population is the highest energy population for all $n_H/n_C$ ratios. For all C$_{24}$H$_n${n=0,6,12,18,24} clusters, a detailed study of the evolution of the carbon ring size distribution as a function of energy clearly shows that the stability is correlated to the number of 6-carbon rings. A similar study for hybridization $sp^n$ (n=1-3) shows that the number of $sp^1$ carbon atoms increases with energy while globally the number of $sp^3$ carbon atoms increases with $n_H/n_C$. The average values of the ionization potentials of all populations were found to decrease when $n_H/n_C$ increases, ranging from 7.9\,eV down to 6.4\,eV that we correlated to carbon atoms hybridization $sp^n$ (n=1-3). These results are of astrophysical interest as they should be taken into account in astrophysical models especially regarding the role of carbonaceous species in the gas ionization.

physics.chem-ph↗