Article
Materials Science, Multidisciplinary
Shota Ono, Tasuku Ito
Summary: The research investigates the dynamical stability of Lennard-Jones crystals in both 2D and 3D structures, categorizing them into four groups based on different (m, n) pairs. Instabilities of various structures are studied within analytical expressions, and the relationship between LJ crystals and elemental metals in the periodic table is discussed.
Article
Multidisciplinary Sciences
Yilong Zhou, Gaurav Arya
Summary: This research paper presents a method for self-assembling binary nanoparticle superlattices using fluid-fluid interfaces. By varying the size ratio, interaction strength, and miscibility of the nanoparticles with the fluids, different structures of 2D superlattices can be formed. The results suggest that the interfacial assembly approach is a versatile platform for fabricating 2D colloidal superlattices with tunable structure and properties.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Benjamin W. B. Shires, Chris J. Pickard
Summary: Energy landscapes serve as a conceptual framework for structure prediction, with a focus on understanding their topological features for efficient exploration methods. SHEAP, inspired by state-of-the-art dimensionality reduction algorithms, demonstrates effective visualization of energy landscapes through applications to various systems.
Article
Chemistry, Physical
Saeed Mehri, Trond S. Ingebrigtsen, Jeppe C. Dyre
Summary: This study investigates physical aging through computer simulations of a 2:1 Kob-Andersen binary Lennard-Jones mixture. Despite significantly larger temperature jumps being studied, the four quantities monitored conform to a single-parameter aging scenario derived from experiments. The relaxing parts of these quantities are almost identical for all temperature jumps, confirming a common material time for aging.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Mathematics, Applied
Laurent Betermin, Ladislav Samaj, Igor Travenec
Summary: This paper investigates the energy minimization problem of Riesz potential and Lennard-Jones potential. In the Riesz case, it is found that the body-centered-cubic (BCC) lattice exhibits global minimality at fixed density, and the hexagonal close-packing (HCP) lattice has higher energy than the face-centered-cubic (FCC) and BCC lattices. In the Lennard-Jones case with exponents above 3, the BCC lattice shows global minimality at free density.
STUDIES IN APPLIED MATHEMATICS
(2023)
Article
Astronomy & Astrophysics
Ali Pourmand, Natalia Ivanova
Summary: Evolutionary calculations for stars in close binary systems are important for understanding gravitational-wave source progenitors and transient events from stellar interactions. Modern 1D stellar codes use the Roche lobe radius concept to treat stars in binary systems. Effective acceleration affects the evolution of stars in close binary systems, which is different from the gravity inside a single star.
ASTROPHYSICAL JOURNAL
(2023)
Article
Mathematics, Applied
Tao Luo, Yang Xiang, Nung Kwan Yip
Summary: This paper analyzes a one-dimensional discrete system to reveal the mechanism of step-bunching phenomenon for epitaxial growth on vicinal surfaces. The study provides systematic analysis of step configurations and minimum energy values, showing a phase transition between bunching and non-bunching regimes. The results also extend the technique and results of previous studies, demonstrating that the classical LJ (6,12) potential does not exhibit the step-bunching-type phenomenon.
JOURNAL OF NONLINEAR SCIENCE
(2021)
Article
Chemistry, Physical
Pasquale Digregorio, Demian Levis, Leticia F. Cugliandolo, Giuseppe Gonnella, Ignacio Pagonabarraga
Summary: The study provides a comprehensive quantitative analysis of topological defects in 2D passive and active repulsive Brownian disk systems. It reveals that the transition from solid to hexatic phase is driven by the unbinding of dislocations, while extended clusters of defects dominate below the solid-hexatic critical line. Moreover, in high activity regimes, dense phases generated by Motility-Induced Phase Separation exhibit rich topological defect structures.
Article
Multidisciplinary Sciences
Hideki Kanda, Wahyudiono, Motonobu Goto
Summary: By performing a large-scale molecular dynamics simulation, the Tolman length and interfacial tension of partially miscible symmetric binary LJ fluids were studied. It was found that two surfaces of tension exist in symmetric binary LJ fluids, and the temperature range and interaction epsilon(AB) affecting the partial mixing of the two fluids were clarified. The results show that the Tolman length increases and the interfacial tension decreases as the temperature or epsilon(AB) increases.
Article
Physics, Multidisciplinary
Jian Lu, Li He, Zachariah Addison, Eugene J. Mele, Bo Zhen
Summary: This study theoretically analyzes the Floquet topological crystalline phases in driven one-dimensional photonic crystals mediated by second-order optical nonlinearity. The photonic Berry connection and polarization are defined in such systems using different methods, and their equivalence is proved. Two examples of topological phase transitions are presented, where two Floquet bands cross and open new gaps under the driving field. The physical consequences of each topological phase transition are analyzed by examining edge states and filling anomalies, with the aim of realizing robust reconfigurable photonic cavities with topologically protected light confinement.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Carlos Handrey Araujo Ferraz
Summary: Studies on random packing of bidispersive particles have shown that such systems can capture the underlying behavior of more complex phenomena found in physics and materials engineering. The understanding the dynamics of these processes is of great theoretical and practical interest because bidispersive particles are used in industry to increase density and fluidity of compounds. This paper uses molecular dynamics simulations to study the packing process of particles with binary size distribution and considers different particle population densities and size ratios.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2021)
Article
Physics, Mathematical
Giancarlo Benettin, Giuseppe Orsatti, Antonio Ponno
Summary: We prove that the commonly used Mie-Lennard-Jones molecular potentials, when appropriately normalized, converge to the Toda exponential potential in the limit of hard-core repulsion. This means that chains of particles interacting through typical molecular potentials exhibit unexpected closeness to integrability. The numerical illustration further shows that even the standard 12-6 MLJ potential is closer to integrability compared to the more commonly used FPU potentials in the literature.
JOURNAL OF STATISTICAL PHYSICS
(2023)
Article
Thermodynamics
Ying Li, Yuxin Gui, Xiaoqing You
Summary: The binary diffusion coefficients of fuel molecules in bath gasses are vital for accurately predicting flame properties. This study evaluates various methods for calculating the diffusion coefficients of n-alkanes in gas mixtures and compares them with experimental data and molecular dynamics simulations.
COMBUSTION AND FLAME
(2023)
Article
Physics, Fluids & Plasmas
Dingwen Qian, Monica Olvera de la Cruz
Summary: In this study, we investigate oppositely charged colloids with size and charge asymmetry under the influence of an external electric field. The large colloidal particles are connected by harmonic springs, arranging themselves into a hexagonal lattice, while the small particles demonstrate fluid-like motion without bonds. Our findings reveal that the system exhibits cluster formation with stable wave packets in the vibrations of the large particles when the external driving force exceeds a critical value.
Article
Physics, Multidisciplinary
Noam Abadi, Franco Ruzzenenti
Summary: Complex networks is a discipline aimed at understanding large interacting systems. This research establishes a relation between the interactions of a system and the networks structure that emerges. Using a Lennard-Jones particle system as an example, the study demonstrates how the physical arrangement of interacting particles can be interpreted as a binary approximation to the interaction potential. This approximation simplifies the calculation of the partition function of the system and allows for the study of the stability of the interaction structure. The results from simulations and the approximated partition function are compared to show the complementarity of the network and system perspective.
Article
Chemistry, Physical
Ujjwal Kumar Nandi, Walter Kob, Sarika Maitra Bhattacharyya
Summary: The study proposes a novel model for a glass-forming liquid that introduces additional particle-particle interactions to alter the liquid's properties. The system's structure remains unchanged, but dynamics are affected, resulting in slower relaxation dynamics, increased onset and mode-coupling temperatures. As the system approaches a mean-field-like state, dynamic heterogeneity decreases, while the non-Gaussian parameter remains unaffected.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Multidisciplinary
Zhen Zhang, Simona Ispas, Walter Kob
Summary: Using atomistic computer simulations, we studied the roughness and topographical features of melt-formed and fracture surfaces of oxide glasses. We found that fracture surfaces are significantly rougher than melt-formed surfaces, with their topography strongly dependent on glass composition. The height-height correlation function for fracture surfaces exhibits a logarithmic dependence on distance, contrary to the power law seen in experiments.
PHYSICAL REVIEW LETTERS
(2021)
Article
Polymer Science
Valerio Sorichetti, Andrea Ninarello, Jose M. Ruiz-Franco, Virginie Hugouvieux, Walter Kob, Emanuela Zaccarelli, Lorenzo Rovigatti
Summary: The study investigates the elastic properties of randomly cross-linked polymer networks, finding that the shear modulus is dependent on the number of chains and chain-length distribution, which is controlled by the preparation protocol. The results show that predicting elastic properties accurately requires knowledge of the exact chain conformation distribution.
Article
Materials Science, Ceramics
John C. Mauro, Charles R. Kurkjian, Prabhat K. Gupta, Walter Kob
Summary: Various impurities in silica glass samples have a significant impact on the glass transition temperature, which can vary by nearly 300 K depending on the type of dopant. A common crossover point is found for all viscosity curves around 2200-2500 K, indicating a change in the transport mechanism from intrinsic defects at high temperatures to dopant-induced defects at low temperatures.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Polymer Science
Valerio Sorichetti, Virginie Hugouvieux, Walter Kob
Summary: Using molecular dynamics simulations, this study investigates the static and dynamic properties of spherical nanoparticles embedded in a disordered and polydisperse polymer network. The study identifies three different dynamical regimes for the nanoparticles based on the confinement parameter C. Comparison with existing theories reveals discrepancies in describing the heterogeneous dynamics of NP diffusion at intermediate time scales.
Article
Physics, Multidisciplinary
Houfei Yuan, Zhen Zhang, Walter Kob, Yujie Wang
Summary: Using computed x-ray tomography, the study reveals the three-dimensional structure of binary hard sphere mixtures, showcasing a surprisingly regular order on intermediate and large length scales. The symmetry of this structure is found to depend on the size ratio of the particles q, and an efficient packing of particles is associated with a locally maximally disordered structure.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Zhen Zhang, Simona Ispas, Walter Kob
Summary: In this study, atomistic computer simulations are used to establish a connection between the stress-strain relation and microscopic properties of silicate glasses. The mobility of modifiers is identified as the mechanism responsible for the complex dependence of stress on strain.
Article
Chemistry, Physical
Jiting Tian, Walter Kob, Jean-Louis Barrat
Summary: Quasi-2D colloidal suspensions in a slit geometry exhibit faster diffusion and relaxation compared to their 2D counterparts due to the additional vertical space that allows overlapping of particles in the projected trajectories. The difference in dynamics can be explained by characterizing the systems using a suitable structural quantity instead of surface density. These results have practical implications for 2D colloidal experiments and provide insights into the 3D-to-2D crossover in glass-forming systems.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Zhen Zhang, Simona Ispas, Walter Kob
Summary: Large-scale simulations have shown that sodium-silicate glasses exhibit nanoductility and composition-dependent crack velocity during dynamic fracture. The local properties of these glasses, including composition, structure, and mechanical properties, display heterogeneity in space and their correlation provides insights into the deformation and fracture behavior. Local heating in the crack tip allows relaxation of the glass structure.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Computer Science, Interdisciplinary Applications
D. A. St-Onge, M. Barnes, F. I. Parra
Summary: A novel global gyrokinetic simulation approach is implemented in stella code, utilizing subsidiary expansion of the gyrokinetic equation and global extension of the Grad-Shafranov equation to handle radial profile variation and boundary conditions effectively, eliminating numerical artifacts near radial boundaries.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Chemistry, Physical
Valerio Sorichetti, Andrea Ninarello, Jose Ruiz-Franco, Virginie Hugouvieux, Emanuela Zaccarelli, Cristian Micheletti, Walter Kob, Lorenzo Rovigatti
Summary: We used simulations to self-assemble polymer networks with a mixture of bivalent and tri- or tetravalent patchy particles, resulting in an exponential strand length distribution similar to experimental cross-linked systems. The fractal structure of the network depends on the assembly number density, but systems with the same mean valence and assembly density have the same structural properties. We also examined the dynamics of long strands using the tube model and found a relation between the localization lengths and shear modulus.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Zhikun Zeng, Shuyang Zhang, Xu Zheng, Chengjie Xia, Walter Kob, Ye Yuan, Yujie Wang
Summary: By analyzing particle trajectory data, we have identified two types of effective temperatures in a cyclically sheared granular system. These temperatures, obtained from different methods, show consistent results and provide experimental evidence for the validity of the concept of effective temperature in driven frictional granular systems.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Fluids & Plasmas
D. A. St-Onge, M. Barnes, F. Parra
Summary: We propose a generalized periodic boundary condition for simulations of plasmas with low magnetic shear, which is a limit of the standard twist-and-shift parallel boundary condition. By introducing a phase shift in the binormal direction when crossing the parallel boundary, we can avoid the convective cells that plague simulations of the three-dimensional Hasegawa-Wakatani system. This non-zero phase shift also has measurable effects in periodic low-magnetic-shear gyrokinetic simulations.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Multidisciplinary Sciences
Misaki Ozawa, Yasutaka Iwashita, Walter Kob, Francesco Zamponi
Summary: A recent breakthrough in glass science involves the synthesis of ultrastable glasses using physical vapor deposition techniques. These glasses exhibit increased stability in terms of thermodynamics, kinetics, and mechanics, with significant implications for both fundamental research and practical applications. However, the current deposition technique is limited to specific types of glass-formers and can only produce thin film samples. In this study, a novel approach using random particle bonding is proposed to generate ultrastable glassy configurations in bulk materials. Computer simulations show the effectiveness of this method, which can be applied to various molecular and soft matter systems, offering great potential for the design of a wide range of ultrastable glasses.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Zhen Zhang, Walter Kob, Simona Ispas
Summary: Ab initio molecular dynamics simulations were used to investigate the properties of dry surfaces of pure silica and sodium silicate glasses. The findings show that these surfaces have higher concentrations of dangling bonds and 2M rings compared to bulk samples. Increasing Na2O concentration reduces structural defects, and 2M rings have a unique vibrational signature around 850 cm(-1). The presence of surfaces also affects atomic vibrations and the electronic density of states, with differences attributed to specific structural units and the influence of Na on chemical bonding in the glasses.