Article
Chemistry, Physical
Yao Xuan, Kris T. Delaney, Hector D. Ceniceros, Glenn H. Fredrickson
Summary: This study presents a computational framework that combines deep learning with self-consistent field theory simulations to accelerate the exploration of parameter space for block copolymers. Several innovations and improvements are proposed, including the use of a Sobolev space-trained convolutional neural network to handle the dimension increase of monomer density fields and the introduction of a generative adversarial network (GAN) to predict saddle point density fields. The framework demonstrates its potential in accelerating the discovery of polymer nanostructures through the successful application to 2D cell size optimization.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Alessio Maiezza, Juan Carlos Vasquez
Summary: We introduce the concept of dimensional reduction at high energies in the perturbative formulation of quantum field theory (QFT). Space and momentum integrations are modified by a weighting function, incorporating an effective mass energy associated with the dimensional reduction scale. The quantization of the theory within the canonical formalism leads to finiteness in perturbation theory, absence of renormalon ambiguities, and improved analytic behavior for infinitesimal coupling constant compared to standard QFT. The new approach reproduces known results at low energies. One key feature of this class of models is the coupling constant always reaches a fixed point in the ultraviolet (UV) region, making the models UV complete.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Chemistry, Physical
Apostolos T. Lakkas, Aristotelis P. Sgouros, Constantinos J. Revelas, Doros N. Theodorou
Summary: Polymer/matrix nanocomposites have exceptional properties and promising applications in key industrial sectors. To ensure the best dispersion, nanoparticles are often stabilized by grafting polymer chains on their surface of the same chemical constitution as the matrix. A model is proposed to predict key structural and thermodynamic properties, exploring various regimes and extracting important quantities related to the distribution and configuration of polymer chains.
Article
Materials Science, Multidisciplinary
Olivier Simard, Philipp Werner
Summary: This paper presents the nonequilibrium implementation of the two-particle self-consistent (TPSC) approach, which has been demonstrated to provide a reliable and versatile description of interacting lattice systems. The method captures the effects of local and nonlocal correlations in two -and higher-dimensional systems and satisfies the Mermin-Wagner theorem. The authors demonstrate the performance of nonequilibrium TPSC through calculations of spin and charge response functions, as well as the evolution of effective temperatures in the two-dimensional Hubbard model.
Article
Business
Christian Fisch, Christian Masiak, Silvio Vismara, Joern Block
Summary: Research on ICO investors' motivations reveals that technological motives are the most important, followed by financial and ideological motives. Differences across motives are observed in terms of investors' risk perception, sources of information, and demand for strict regulation.
JOURNAL OF BUSINESS RESEARCH
(2021)
Article
Computer Science, Interdisciplinary Applications
Michael F. Herbst, Antoine Levitt
Summary: In this study, a novel adaptive damping algorithm for self-consistent field (SCF) iterations in Kohn-Sham density-functional theory is proposed. The algorithm adjusts the damping in each SCF step using a backtracking line search based on a theoretically sound and accurate energy model. Unlike traditional SCF schemes, this algorithm is fully automatic and does not require user input for selecting the damping parameter. The algorithm is successfully applied to various challenging systems, including elongated supercells, surfaces, and transition-metal alloys.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Computer Science, Interdisciplinary Applications
Yao Xuan, Kris T. Delaney, Hector D. Ceniceros, Glenn H. Fredrickson
Summary: A new framework using data obtained from SCFT simulations and deep learning is introduced to accelerate the exploration of parameter space for block copolymers. The method focuses on learning an approximation to the effective Hamiltonian and predicting saddle density fields, while ensuring invariance under shifts and rotations. Data-enhancing techniques and appropriate regularization are used to achieve this invariance.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Mathematics, Applied
Rob Claes, Karl Meerbergen
Summary: This paper presents a method that uses multiple previous iterates to build an interpolating first order approximation of the nonlinearity, which converges superlinearly to the desired eigenpair.
APPLIED MATHEMATICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Alexander Duthie, Sthitadhi Roy, David E. Logan
Summary: We present a self-consistent theory of mobility edges in nearest-neighbor tight-binding chains with quasiperiodic potentials, discussing the boundaries between localized and extended states in these systems and demonstrating the agreement of the theory with known mobility edges through two model examples.
Article
Materials Science, Multidisciplinary
Chia-Nan Yeh, Sergei Iskakov, Dominika Zgid, Emanuel Gull
Summary: In this paper, the authors utilized the self-energy embedding theory to study the spectra of SrVO3 and SrMnO3, reaching different conclusions about strongly correlated metals and insulators, showing the potential for systematic study of correlated perovskites.
Article
Mathematics, Applied
Huayi Wei, Xin Wang, Chunyu Chen, Kai Jiang
Summary: In this paper, a high-order adaptive virtual element method (VEM) is proposed for simulating the polymeric self-consistent field model in arbitrary domains. The VEM is flexible in handling general polygon elements and can treat hanging nodes as polygon vertices without additional processing. Additionally, an adaptive method equipped with a new Log marking strategy is presented to effectively simulate the phase separation behavior of strong segregation systems on polygonal meshes. Numerical results demonstrate the efficiency of the developed method in simulating the phase behavior of block polymers on complex geometric domains and the significant reduction in computational cost for strong segregation systems.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)
Article
Physics, Particles & Fields
Chen Lan, Yan-Gang Miao
Summary: In this study, we examine the first law of mechanics for regular black holes in the context of the Gliner vacuum. We propose an improved version of the first law that resembles the first law of thermodynamic systems. By utilizing the modified first law, we establish a theory of Ruppeiner geometry and discover a universal attractive property of the microstructure of regular black holes. Furthermore, we analyze the repulsive and attractive interactions inside and outside regular black holes.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Polymer Science
Hyeongkeon Yoon, Qingshu Dong, Weihua Li, Jin Kon Kim
Summary: Tetragonally and rectangularly packed hierachical cylindrical nanostructures are observed in polystyrene-b-polyisoprene-b-polystyrene-b-poly(2-vinylpyridine) tetrablock terpolymer (S1IS2V) by tailoring the volume fraction of the polystyrene mid-block. The experimentally observed hierarchical cylindrical nanostructures are in good agreement with the prediction by the self-consistent field theory.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Physics, Applied
Adham Naji, Sami Tantawi
Summary: A variational theory is presented for beam loading in microwave cavities, which provides steady-state solutions for the detuning of a cavity's resonant frequency, Q, and optimal coupling coefficient due to beam loading. The derived Lagrangian includes various effects and is applied to predict detuning parameters for maximizing gain in klystron input cavities. The formulation offers advantages for analyzing and designing beam-loaded cavity structures, providing a self-consistent model for beam-field interaction and guiding cavity-shape optimization.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Condensed Matter
Michael F. Herbst, Antoine Levitt
Summary: A new preconditioner based on the local density of states has been proposed for solving the self-consistent problem in Kohn-Sham density functional theory. It is cost-effective and addresses the issue of long-range charge sloshing in large, inhomogeneous systems. The preconditioner is applicable to metals, insulators, and semiconductors, and has been successfully tested on various types of inhomogeneous systems.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Physics, Multidisciplinary
Qiyun Tang, Marcus Mueller
Summary: Numerical calculations demonstrate an anomalous liquid expansion when quenching a binary mixture to low pressures in the vapor phase. This evaporation-induced expansion is attributed to pressure imbalance near the liquid-vapor interface, influenced by the complex thermodynamics and dynamic asymmetries of binary mixtures. Careful modulation of pressure quench in the vapor phase can induce spinodal bubble formation inside the liquid phase.
PHYSICAL REVIEW LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Xavier Chevalier, Cindy Gomes Correia, Gwenaelle Pound-Lana, Philippe Bezard, Matthieu Serege, Camille Petit-Etienne, Guillaume Gay, Gilles Cunge, Benjamin Cabannes-Boue, Celia Nicolet, Christophe Navarro, Ian Cayrefourcq, Marcus Mueller, Georges Hadziioannou, Ilias Iliopoulos, Guillaume Fleury, Marc Zelsmann
Summary: This study introduces a novel top-coat material that can mechanically confine the BCP layer through cross-linking reactions, suppressing dewetting while promoting perpendicular orientation, addressing critical issues in DSA. Selection of areas of interest directly on the TC layer and lithography steps can generate locally controlled BCP patterns and nanostructured BCP multilayers.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Biophysics
Y. G. Smirnova, M. Mueller
Summary: Molecular simulations show that strong membrane curvature significantly increases the thermodynamic stability of the hourglass-shaped connection between vesicles, while the reduction of the barrier to stalk formation is due to the lower dehydration free energy required for highly curved vesicles compared to apposing, planar membranes.
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS
(2021)
Article
Polymer Science
Yaron Aviv, Esra Altay, Ofer Burg, Marcus Mueller, Javid Rzayev, Roy Shenhar
Summary: The research demonstrates that the nature of the substrate has a significant impact on the self-assembled morphology and surface patterns of bottlebrush block copolymers with different side-chain lengths in films, despite the typical tendency of these polymers to form lamellar structures. By manipulating the substrate chemistry, unique morphologies can be induced in bottlebrush block copolymer films.
Article
Polymer Science
Alireza F. Behbahani, Ludwig Schneider, Anastassia Rissanou, Anthony Chazirakis, Petra Bacova, Pritam Kumar Jana, Wei Li, Manolis Doxastakis, Patrycja Polinska, Craig Burkhart, Marcus Mueller, Vagelis A. Harmandaris
Summary: A hierarchical simulation methodology is proposed for predicting the dynamical and rheological properties of entangled polymer melts, which includes atomistic, moderately coarse-grained (mCG), and highly coarse-grained slip-spring (SLSP) simulations. The methodology matches local structural distributions of the different levels and uses compensating pair potentials to keep static macromolecular properties unaltered.
Article
Chemistry, Physical
Marcus Mueller
Summary: Using analytical considerations and particle-based simulations, this study investigates the relaxation of a density modulation in a polymer system without nonbonded interactions. The results demonstrate that shallow density modulations, prepared by different processes but with identical amplitudes and wavevectors, exhibit different nonexponential decay behaviors, challenging the assumption that density alone characterizes the polymer system configuration. Analytic descriptions within Linear-Response Theory (LRT) and the Rouse model are provided, showing quantitative agreement with the particle-based simulations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Cody T. Bezik, Joshua A. Mysona, Ludwig Schneider, Abelardo Ramirez-Hernandez, Marcus Mueller, Juan J. de Pablo
Summary: A new mesophase in binary blends of A-b-(BA')3 miktoarm star block copolymers and A homopolymers has been discovered, consisting of aperiodic discrete domains of A embedded in a continuous matrix of B. Molecular bridging dominates the mechanical behavior of the mesophase, outweighing the influence of microphase segregation. The application of shear leads to a closer structure resembling its speculated discrete nature.
Article
Polymer Science
Gaoyuan Wang, Marcus Mueller
Summary: This study investigates the interplay between elasticity and microphase separation in quasi-two-dimensional phantom networks formed by AB diblock copolymers. Computer simulations and phenomenological considerations show that network elasticity has a minor role in the system when the stretching is weak. As the stretching increases, the incompatibility for the order-disorder transition decreases, and a multigrain state with tilted lamellae is observed at intermediate stretching.
Article
Chemistry, Physical
David Steffen, Ludwig Schneider, Marcus Mueller, Joerg Rottler
Summary: This paper investigates the spatiotemporal autocorrelation of shear stress in a supercooled fluid close to the glass transition using molecular dynamics simulations. The results show anisotropic correlations and strongly damped oscillations at non-zero wavevectors. The experimental findings are in good quantitative agreement with a recently developed hydrodynamic theory.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Gaoyuan Wang, Annette Zippelius, Marcus Mueller
Summary: Cross-linking is a versatile strategy to stabilize the structure and control the dynamics of polymers. This study systematically investigates the phase behavior of randomly cross-linked diblock copolymer melts and reveals the significant influence of the preparation state on the phase diagram.
Article
Polymer Science
Pritam Kumar Jana, Petra Bacova, Ludwig Schneider, Hideki Kobayashi, Kai-Uwe Hollborn, Patrycja Polinska, Craig Burkhart, Vagelis A. Harmandaris, Marcus Mueller
Summary: The theological properties of polymer composites depend on the interfacial interactions between solid fillers and a polymer fluid. This study presents a simulation strategy called the wall-spring thermostat, which uses transient bonds to mimic the interactions between the polymer and the solid surface. The density and lifetime of these transient bonds can be adjusted to control the single-chain and collective dynamics of the polymer at the surface. The simulation technique allows for the capture of dynamic heterogeneities at surfaces.
Article
Chemistry, Physical
Kai-Uwe Hollborn, Ludwig Schneider, Marcus Muller
Summary: Highly coarse-grained (hCG) linear polymer models, based on dissipative particle dynamics (DPD), allow for studying long time and length scales. This top-down strategy uses relevant interactions, such as molecular connectivity, and coarse-grained invariants, like the mean-squared end-to-end distance, to describe the equilibrium behavior of long, flexible macromolecules. However, describing the dynamics of long, entangled polymers is challenging because hCG models do not enforce the noncrossability of molecular backbones. One technique to mimic entanglements in hCG models is slip-springs, which has shown quantitative agreement with simulations, experiments, and theoretical predictions.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Polymer Science
Oliver Dreyer, Gregor Ibbeken, Ludwig Schneider, Niklas Blagojevic, Maryam Radjabian, Volker Abetz, Marcus Mueller
Summary: In this study, the self-assembly of asymmetric diblock copolymers during solvent evaporation was investigated using particle-based Monte Carlo simulations and continuum modeling. The effects of evaporation rate and solvent selectivity on structure formation, particularly the alignment of minority block cylinders, were examined. Comparing the two simulation techniques helped identify general trends with parameter variation and understand the role of single-chain dynamics, fluctuations, and additional model details.
Article
Chemistry, Physical
Felix Weissenfeld, Lucia Wesenberg, Masaki Nakahata, Marcus Mueller, Motomu Tanaka
Summary: The interactions between vesicle and substrate were investigated using simulation and experiment. Polyacrylic acid brushes with cysteine side chains were grafted onto planar lipid membranes. The addition of Cd2+ ions compacted the polymer brushes and influenced the adhesion of lipid vesicles. Wetting of the vesicles occurred at [CdCl2] = 0.25 mM. The shape and adhesion of vesicles were quantitatively evaluated, and simulations revealed that wetting sensitivity was dependent on the interaction range.
Article
Polymer Science
Niklas Blagojevic, Marcus Mueller
Summary: Using a particle-based model, a free-energy functional, and a lattice model, this study investigates the structure and motion of a grain boundary between two orthogonal grains in asymmetric block copolymers. The study reveals insights into transitions and correlations in space and time. By characterizing the system using a free-energy functional and calculating the minimum free-energy path, the study identifies a minimal set of transitions. The results are used to parametrize a lattice model and investigate grain-boundary motion by kinetic Monte Carlo simulation.
