Article
Chemistry, Multidisciplinary
Nguyet N. T. Pham, Seong Hun Han, Jong S. Park, Seung Geol Lee
Summary: Organic-molecule fluorophores with emission wavelengths in the NIR-II have excellent resolution and sensitivity, but lack adequate theoretical levels for efficient estimations of their optical and electronic properties. The GW approximation combined with the Bethe-Salpeter equation (GW-BSE) was used in this study to calculate the excited states of two NIR molecular fluorophores, showing excellent agreement with experimental results.
Article
Computer Science, Interdisciplinary Applications
P. Arthuis, A. Tichai, J. Ripoche, T. Duguet
Summary: The second version of the code ADG automates the generation and evaluation of valid off-diagonal Bogoliubov many-body perturbation theory diagrams. It can handle Hamiltonians with both two-body and three-body interactions, and utilizes algebraic Feynman's rules and diagrammatic rules for evaluation. The program has been optimized for efficiency and moved to Python3, while still supporting Python2.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Evan Sheridan, Christopher Rhodes, Francois Jamet, Ivan Rungger, Cedric Weber
Summary: Machine learning provides new possibilities for modeling correlated materials, but quantum embedding methods like dynamical mean-field theory face limitations on classical computing architectures. A data-driven machine learning process has been outlined for solving the Anderson impurity model, improving the accuracy and speed of solutions. This approach, known as data-driven dynamical mean-field theory (d3MFT), advances the field by enabling faster and more accurate calculations of strongly correlated materials.
Article
Physics, Condensed Matter
Luong Thi Ta, Yoshitada Morikawa, Ikutaro Hamada
Summary: The electronic and optical properties of the hydrogen boride sheet were studied using the many-body perturbation theory with the perturbative GW (G(0)W(0)) approximation. It was found that the hydrogen boride sheet exhibits a semimetallic electronic structure, confirming previous theoretical studies. Additionally, the optical spectrum calculated based on quasiparticle energies agrees well with experimental results. This work suggests that the G(0)W(0) approximation may be valuable for predicting precise electronic and optical properties of the hydrogen boride sheet and its derivatives.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Ziyang Wei, Philippe Sautet
Summary: Copper is the most important catalyst for the carbon dioxide reduction reaction (CO2RR), but traditional methods have difficulties in studying the mechanism. This study used a more accurate method to investigate the CO2RR mechanism on Cu(100) facet.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Materials Science, Multidisciplinary
James Nelson, Rajarshi Tiwari, Stefano Sanvito
Summary: The study presents a machine-learning density-functional theory applicable to the spinless Hubbard model in one dimension, establishing relationships between site occupation and total energy or Helmholtz free energy at both zero and finite temperatures. The resulting functionals are semilocal and independent of system size, constructed through neural networks over exact data for small systems. Neural networks are also defined for finite-temperature thermodynamic quantities, providing access to properties of many-body systems at finite temperatures in the thermodynamic limit.
Article
Physics, Condensed Matter
Raymond Amador, Holger-Dietrich Sassnick, Caterina Cocchi
Summary: This study investigates the electronic structure and dielectric response of multi-alkali antimonides, focusing on Na2KSb and NaK2Sb. Both materials have a direct band gap, with the imaginary part of the dielectric function showing maxima in the near-infrared region extending to visible and ultraviolet bands. The lowest-energy excitations are non-excitonic and have a binding energy of around 100 meV, confirming the potential of Na2KSb and NaK2Sb as photoemissive materials for various applications.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Chemistry, Physical
Alexander E. Doran, So Hirata
Summary: A scalable stochastic algorithm for evaluating fourth-order many-body perturbation (MP4) correction to energy has been proposed. The algorithm involves computer-generated diagrams and algebraic formulas expressed in terms of Green's functions, and is evaluated using Monte Carlo integration accelerated by redundant walker and control variate algorithms. The resulting MC-MP4 method is efficiently parallelized with significantly lower cost dependence compared to deterministic MP4 algorithm. It has been shown to accurately evaluate the energy of various molecules with a statistical uncertainty within a certain range after a large number of Monte Carlo steps.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Mathematics, Applied
Carlos Barrera, Abimael Bengochea, Carlos Garcia-Azpeitia
Summary: The study focuses on the time-dependent restricted (n + 1)-body problem, examining periodic solutions for a massless body (satellite) under the gravitational influence of n primary bodies. The satellite is shown to have periodic solutions near large-amplitude circular orbits (comet solutions) and small-amplitude circular orbits near a primary body (moon solutions). The comet and moon solutions are constructed using Lyapunov-Schmidt reduction and reversibility techniques, with numerical computations done for four primaries following the super-eight choreography.
JOURNAL OF DYNAMICS AND DIFFERENTIAL EQUATIONS
(2022)
Article
Physics, Condensed Matter
Yuhit Gupta, M. M. Sinha, S. S. Verma
Summary: In this study, the lattice dynamical properties and other properties of Full Heusler alloy 'MnY2Ga' were investigated using first-principles density functional perturbation theory and density functional theory. It was found that the spin-polarization ratio for MnY2Ga is -31.6%, indicating its false half-metallic character. This work also determined the phonon dispersion spectra, phonon density of states, and different phonon modes for the first time, and discussed the effects of spin on atomic interactions and lattice structure.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Physics, Multidisciplinary
Heikki Mantysaari, Bjorn Schenke, Chun Shen, Wenbin Zhao
Summary: We find that exclusive vector meson production at high energy within the color glass condensate framework is highly sensitive to the geometric deformation of the target nucleus at multiple length scales. Different multipole deformation parameters affect different regions of transverse momentum transfer. These results have two important implications: (1) Deformations of nuclear targets must be considered when predicting and interpreting certain observables at the EIC. (2) Differential diffractive vector meson production has the potential to be a powerful tool for directly measuring nuclear structure at different length scales.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
P. Demol, M. Frosini, A. Tichai, V. Soma, T. Duguet
Summary: A novel many-body method called Bogoliubov many-body perturbation theory (BMBPT) has been developed to accurately and efficiently solve the A-body Schrödinger equation for open-shell nuclei. The perturbation theory must operate under the constraint that the average number of particles is self-consistently adjusted at each perturbative order, and it has been shown that using a resummation method like eigenvector continuation can improve accuracy and convergence towards CI results.
Article
Mathematics, Applied
Mohamed El-Borhamy, Essam Eddin M. Rashad, Arafa A. Nasef, Ismail Sobhy, Samah M. Elkholy
Summary: This article discusses the stability of periodic responses for AC machines using the Lyapunov function approach. The equivalent linear RLC series circuit model and the linear differential equation with periodic coefficients are used to derive special relationships among circuit parameters to ensure stability and periodic structure. The periodic structure of responses is obtained through strained parameters and compared with experimental results, showing strong agreement. Additionally, future points for discussion are raised to improve the mathematical modeling of AC machines for better model and simulation.
Article
Chemistry, Physical
Sandip Aryal, Joseph Frimpong, Zhen-Fei Liu
Summary: Quantum dot (QD) assemblies are nanostructures formed by aggregates of QDs, which exhibit improved charge and energy transfer efficiencies compared to isolated QDs. Our study systematically compares the electronic and optical properties of two types of CdS QD assemblies and highlights the impact of assembly dimensionality on these properties. We also reveal the crucial role of covalent bonds in exciton localization, distinguishing QD gels from QD nanocrystals.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Physics, Multidisciplinary
M. J. Hyrkas, D. Karlsson, R. van Leeuwen
Summary: This paper presents an improved diagrammatic approximation method to preserve the positivity of observables at finite temperature. By using cutting rules, it solves the problem of negative spectral densities and non-vanishing vacuum diagrams, and also derives an analytic continuation relation between retarded N-point functions and their Matsubara counterparts.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Chemistry, Physical
J. Arjan Berger, Pierre-Francois Loos, Pina Romaniello
Summary: This study demonstrates the advantages of using the COHSEX approach in calculating potential energy surfaces, showing smoother results compared to other methods. The use of self-consistent COHSEX QP energies and orbitals can lead to results independent of the starting point and improved equilibrium distances. The total energies may worsen with self-consistency, but the equilibrium distances are improved due to changes in screening within the Bethe-Salpeter equation.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Multidisciplinary
S. Di Sabatino, J. Koskelo, J. Prodhon, J. A. Berger, M. Caffarel, P. Romaniello
Summary: The Extended Koopman's Theorem (EKT) and Many-body Effective Energy Theory (MEET) are connected and can benefit from each other. By solving the secular equation of EKT, a more optimal basis set for MEET can be chosen. The findings are illustrated with examples of the Hubbard dimer and bulk silicon.
FRONTIERS IN CHEMISTRY
(2021)
Article
Chemistry, Physical
H. J. Kulik, T. Hammerschmidt, J. Schmidt, S. Botti, M. A. L. Marques, M. Boley, M. Scheffler, M. Todorovic, P. Rinke, C. Oses, A. Smolyanyuk, S. Curtarolo, A. Tkatchenko, A. P. Bartok, S. Manzhos, M. Ihara, T. Carrington, J. Behler, O. Isayev, M. Veit, A. Grisafi, J. Nigam, M. Ceriotti, K. T. Schuett, J. Westermayr, M. Gastegger, R. J. Maurer, B. Kalita, K. Burke, R. Nagai, R. Akashi, O. Sugino, J. Hermann, F. Noe, S. Pilati, C. Draxl, M. Kuban, S. Rigamonti, M. Scheidgen, M. Esters, D. Hicks, C. Toher, P. Balachandran, I Tamblyn, S. Whitelam, C. Bellinger, L. M. Ghiringhelli
Summary: Computational materials science is experiencing a paradigm shift, with traditional methods being replaced by faster, simpler, and more accurate machine learning approaches. This article discusses the use of machine learning in materials science, with contributions from experts in the field, and shares perspectives on current and future challenges.
ELECTRONIC STRUCTURE
(2022)
Article
Physics, Multidisciplinary
Gabriele Riva, Timothee Audinet, Matthieu Vladaj, Pina Romaniello, J. Arjan Berger
Summary: This article presents an original strategy for calculating direct and inverse photoemission spectra from first principles. The main goal is to go beyond standard Green's function approaches and accurately describe both quasiparticles and satellite structures in strongly correlated materials. The authors use the three-body Green's function as a key quantity and demonstrate how to retrieve the one-body Green's function from it. They also find that satellite information is already present in the non-interacting three-body Green's function and that simple approximations to the three-body self-energy can yield accurate spectral functions.
Article
Chemistry, Physical
Xabier Telleria-Allika, Miguel Escobar Azor, Gregoire Francois, Gian Luigi Bendazzoli, Jon M. Matxain, Xabier Lopez, Stefano Evangelisti, J. Arjan Berger
Summary: “”In this work, the Wigner localization of interacting electrons in a one-dimensional harmonic potential is studied using accurate quantum chemistry approaches. The results show that the Wigner regime can be achieved with small values of the confinement parameter. A semi-analytical model for two electrons is used to gain insights into the results. By analyzing electronic structure properties such as the one-body density and the particle-hole entropy, a path connecting the Wigner regime to the Fermi-gas regime is defined by varying the confinement parameter. The particle-hole entropy exhibits a maximum that could be interpreted as the transition point between the localized and delocalized regimes.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Martin Kuban, Simon Gabaj, Wahib Aggoune, Cecilia Vona, Santiago Rigamonti, Claudia Draxl
Summary: This article introduces a method of using spectral fingerprints and similarity metrics to establish quantitative relationships between materials data and demonstrates its application in material assessment and data analysis.
Article
Multidisciplinary Sciences
Martin Kuban, Santiago Rigamonti, Markus Scheidgen, Claudia Draxl
Summary: We developed a materials descriptor based on electronic density-of-states and studied the similarity of materials using it. By applying this descriptor and a clustering algorithm in the Computational 2D Materials Database, we identified groups of materials with similar electronic structures and introduced additional descriptors to characterize these clusters. This allowed us to analyze the database automatically and explain the (dis)similarities found.
Article
Physics, Multidisciplinary
Benedikt Hoock, Santiago Rigamonti, Claudia Draxl
Summary: The main goal of data-driven materials research is to find optimal low-dimensional descriptors that can predict physical properties and interpret them in a human-understandable way. This work proposes a method to identify descriptors using compressed sensing, by constructing candidate features based on simple basic properties and selecting the most relevant features using cross-validation.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Condensed Matter
Lara Kabalan, Igor Kowalec, Santiago Rigamonti, Maria Troppenz, Claudia Draxl, C. Richard A. Catlow, Andrew J. Logsdail
Summary: Computational simulation using multiscale modelling approaches is used to explore the phase stability and phase diagram of PdZn binary alloys. The results identify the stability ranges of different phases and provide a platform for future investigations of close-packed alloy systems.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Physics, Multidisciplinary
Maria Troppenz, Santiago Rigamonti, Jorge O. Sofo, Claudia Draxl
Summary: In the pursuit of efficient thermoelectrics, achieving semiconducting behavior is challenging due to the complex interplay between electronic structure, temperature, and disorder. This study focuses on the thermoelectric clathrate Ba8Al16Si30, which exhibits a band gap in its ground state. However, a temperature-driven partial order-disorder transition effectively closes the gap, as demonstrated by a novel method that considers the effects of short-range order in complex alloys.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Gregoire Francois, Celestino Angeli, Gian Luigi Bendazzoli, Veronique Brumas, Stefano Evangelisti, J. Arjan Berger
Summary: The electric polarizability and spread of the total position tensors can be used to characterize the metallic or insulator nature of large systems. This study introduces the concept of Clifford boundary conditions, which modifies the topology of a finite fragment extracted from a periodic system into that of a Clifford torus, enabling a simplified treatment of carbon nanotubes. The results show that at the Huckel level, finite or periodic carbon nanotubes can be considered as a collection of non-interacting dimerized linear chains, allowing for a description of their properties and identification of peculiar behaviors.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Amer Alrakik, Miguel Escobar Azor, Veronique Brumas, Gian Luigi Bendazzoli, Stefano Evangelisti, J. Arjan Berger
Summary: This paper investigates the minimum energy configuration problem of conductive electrons with different topological structures, including a 2-dimensional sphere and multi-dimensional Clifford torus. The equilibrium configurations and energy spectra are obtained through numerical and analytical methods. The research findings are of significance for describing periodic systems and understanding the structure of Wigner crystals.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Materials Science, Multidisciplinary
S. Di Sabatino, J. Koskelo, J. A. Berger, P. Romaniello
Summary: By introducing electron screening, the band-gap opening in weakly as well as strongly correlated systems can be correctly described. This method has been applied to bulk LiH, Si, and paramagnetic as well as antiferromagnetic NiO, demonstrating its effectiveness. Although some incorrect features still exist in the full photoemission spectra, this result is significant for an ab-initio electronic structure method and paves the way for a unified description of photoemission spectra at weak and strong correlation.
Article
Materials Science, Multidisciplinary
Stefano Evangelisti, Faten Abu-Shoga, Celestino Angeli, Gian Luigi Bendazzoli, J. Arjan Berger
Summary: In this work, we prove the uniqueness of the one-body position operator for periodic systems that we recently proposed. The proof relies on several general physical constraints that a periodic one-body position operator should satisfy, and demonstrates that these constraints are sufficient to uniquely define a position operator that is compatible with periodic boundary conditions.
Article
Materials Science, Multidisciplinary
S. Di Sabatino, J. Koskelo, J. A. Berger, P. Romaniello
Summary: This work investigates the impact of reduced density matrix functionals on the performance of the extended Koopmans' theorem (EKT) and finds that in strongly correlated materials, the EKT method can open a band gap but with an overestimation, which can be reduced by using approximate density matrices.