Article
Nanoscience & Nanotechnology
Francisco A. G. de Lira, Edilberto O. Silva
Summary: An alternative theoretical approach based on the geometry of the states space is proposed to describe the physical properties of a single quantum dot. Analytical expressions for the Fermi energy and density of states were obtained, allowing for the study of electron states and thermodynamic properties of the system. The technique is found to be more suitable for devices with a large number of electrons and provides limitations for the system through magnetic and temperature control. Comparisons with literature results were also conducted.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2023)
Article
Chemistry, Physical
Chengzhen Sun, Kailin Luo, Runfeng Zhou, Bofeng Bai
Summary: The theoretical model accurately predicts the surface molecular permeation through two-dimensional graphene nanopores, especially for strongly adsorbed molecules. It is competent in describing both the overall permeation flux and detailed density distribution.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Vadim V. Varlamov, Larisa D. Pavlova, Olga S. Babushkina
Summary: This paper discusses the group theoretical description of the periodic system of elements within the Rumer-Fet model. The concept of a single quantum system is introduced, with the generating core being an abstract C*-algebra. It is shown that the implementation of operator algebra depends on the structure of the generators of the fundamental symmetry group attached to the energy operator. The paper also introduces a mass formula for the main multiplet of the Rumer-Fet group and calculates the masses of elements in the Seaborg table.
Review
Chemistry, Physical
Jeroen van der Mynsbrugge, Alexis T. Bell
Summary: Zeolites are widely used as catalysts in various industries, leading to a growing interest in describing the mechanism and kinetics of zeolite-catalyzed reactions using theoretical methods. Accurate prediction of adsorption and activation enthalpies and entropies requires consideration of factors such as the structure of the catalytically active center and the level of density functional theory (DFT). Successful application of hybrid quantum mechanics/molecular mechanics (QM/MM) with high-level exchange-correlation functional and large basis set has been demonstrated for reactions involving light alkanes and protonated zeolites, showing good predictions for adsorption enthalpies and activation enthalpies at different temperatures.
JOURNAL OF CATALYSIS
(2021)
Article
Astronomy & Astrophysics
Martin Bojowald, Ding Ding
Summary: This article introduces new models for cosmological dynamics that take into account quantum correlations between background and perturbations, as well as cross-correlations between different modes of a quantum field. The evolution equations for moments of a perturbation state reveal the conditions necessary for the formation of inhomogeneity from an initial vacuum. Quantum non-locality plays a crucial role in formulating a local theory with non-classical degrees of freedom represented by moments of a quantum state using canonical methods.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Chemistry, Physical
Amanda J. Carr, Raju R. Kumal, Wei Bu, Ahmet Uysal
Summary: This study investigates the distribution of metal ions and water near graphene oxide films using interface-specific techniques. The results reveal that trivalent yttrium ions preferentially adsorb to graphene oxide and affect its structure, while divalent strontium and monovalent cesium ions have different effects. These findings provide fundamental information about the organization of ions and water at the interface and have relevance for improving graphene oxide membranes and applications downstream.
Article
Materials Science, Multidisciplinary
W. Mabrouki, A. Krichene, N. Chniba Boudjada, W. Boujelben
Summary: This paper presents a theoretical description of the magnetocaloric effect in Pr0.67Sr0.33MnO3 manganite. The mean-field theory is used to simulate the temperature dependence of the magnetic entropy change under several applied magnetic fields around the Curie temperature. The results obtained from the mean-field theory are compared with experimental data, and the excellent agreement between the two methods suggests the validity of the theory for modeling the magnetocaloric properties of the manganite. The study also indicates that the sample can be used as a magnetic refrigerant near room temperature.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Maged Faihan Alotaibi, E. M. Khalil, S. Abdel-Khalek, M. Y. Abd-Rabbou, Mohamed Omri
Summary: This paper investigates the dynamic effects of an external classical field on a system consisting of a single two-level atom interacting with a vibrating graphene membrane and a cavity field. By obtaining the temporal wave function containing tripartite interaction statuses and new resonance conditions, the optimal behavior of quantum coherence and non-classicality for different states is explored. The upper and lower bounds of these phenomena are found to depend on various parameters, and numerical computations are used to demonstrate the control of the quantum system through the vibrating graphene membrane and driven classical field.
RESULTS IN PHYSICS
(2021)
Article
Chemistry, Physical
Wancai Li, Jiaqi Ma, Xue Cheng, Dehui Li
Summary: The optoelectronic performances of layered materials are highly dependent on sample thickness, especially when the size is reduced to nanometer scale where surface effects become significant. In this study, it was found that the photoluminescence quantum yield of 2D perovskite microplates can be greatly enhanced when encapsulated by graphene, providing a cost-effective approach to improve luminescence efficiency.
Article
Multidisciplinary Sciences
Erica Bertolini, Filippo Fecit, Nicola Maggiore
Summary: In this paper, the topological abelian BF theory with radial boundary on a generic 3D manifold is studied, and it is found that the motion of the boundary excitations depends on the non-flat nature of the bulk spacetime. By requiring the Hamiltonian to have a lower bound and time reversal symmetry, different motion patterns for the edge modes are obtained.
Article
Chemistry, Multidisciplinary
Sheida Bagherzadeh-Nobari, Reza Kalantarinejad
Summary: The study investigated the use of armchair graphene nanoribbon (AGNR) as a DNA hybridization detector, and found that functionalization with 1-pyrenebutanoic acid succinimidyl ester (PBASE) increased conductance, while functionalization with probe and target DNA decreased conductance. The changes in conductance were attributed to alterations in the projected density of states on the AGNR and transmission around the Fermi energy. Charge transfer and electrostatic gating were identified as the mechanisms responsible for the changes in electrical properties of the system. The device was able to detect DNA hybridization with a sensitivity of 10% at zero bias voltage, and could achieve higher sensitivity with the application of a suitable gate voltage.
JOURNAL OF NANOPARTICLE RESEARCH
(2021)
Article
Chemistry, Physical
Lijun Liang, Xin Shen, Mengdi Zhou, Yijian Chen, Xudong Lu, Li Zhang, Wei Wang, Jia-Wei Shen
Summary: In this study, molecular dynamics simulation was used to investigate the adsorption behavior and structural changes of single-stranded and double-stranded DNA on the surfaces of graphene quantum dots with different sizes and oxidation levels. The results showed that single-stranded DNA can strongly adsorb and lay flat on the surface, while double-stranded DNA prefers to orient vertically.
Article
Biochemistry & Molecular Biology
Vladislav V. Shunaev, Olga E. Glukhova
Summary: Graphene and magnetite composites show potential for use in flexible energy storage devices due to the excellent properties of these materials. This study used quantum chemical methods to examine how the concentration of magnetite affects the energetic and electronic parameters of the composites. Results show that adding magnetite to graphene can change its zone structure and capacitive properties, allowing the capacity of the composite to be tuned for various supercapacitor applications.
Article
Chemistry, Physical
Azarmidokht Sheini, Avat (Arman) Taherpour, Maryam Maghsudi, Sakineh Farajmand-Amirabadi, Maryam Kouchak, Nadereh Rahbar, Mohammad Sabaeian, Hadis Alidadi
Summary: In this study, nitrogen-doped graphene quantum dots (N-GQDs) were synthesized using an oxidizing agent and amidative agent, showing excellent photothermal conversion efficiency and photoluminescent properties. The structures and properties of the N-GQDs were investigated using various characterization methods and quantum mechanical simulations.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Physics, Condensed Matter
Abinash Panda, Puspa Devi Pukhrambam
Summary: This research presents the design and analysis of a highly sensitive reconfigurable surface plasmon resonance (SPR) sensor for detecting dengue virus. The sensor structure consists of SF11 prism, Ag, graphene, antimony trisulphide (Sb2S3), and sensing medium. By optimizing the geometrical parameters, the sensor achieves high performance. The results show that switching the phase of Sb2S3 significantly increases the sensitivity of the sensor.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Optics
V. V. Sementin, A. P. Pogoda, V. M. Petrov, I. S. Khakhalin, E. E. Popov, N. L. Istomina, A. S. Boreisho
Summary: A digital holographic system for layer-by-layer control of component quality in additive manufacturing was investigated. The system uses a two-wavelength holographic interferometry method and a Michelson interferometer. It records holograms of the surface of each layer at two adjacent wavelengths and determines the depth of defects on the component layer surface by reconstructing the holograms. The system has been shown to be able to detect large irregularities and surface defects with a size of 25 μm.
JOURNAL OF OPTICAL TECHNOLOGY
(2022)
Editorial Material
Astronomy & Astrophysics
Nazar R. Ikhsanov, Galina L. Klimchitskaya, Vladimir M. Mostepanenko
Article
Physics, Applied
E. A. Vashukevich, V. V. Lebedev, I. Ilichev, P. M. Agruzov, A. Shamrai, V. M. Petrov, T. Yu Golubeva
Summary: The theory and practical realization of a broadband quantum-noise generator based on an original integrated optical beam splitter in the form of a Mach-Zehnder interferometer is demonstrated. The beam splitter with a double output, made on a lithium niobate substrate, provides accurate electro-optical balancing of the homodyne quantum-noise detection circuit. The experimentally obtained excess of quantum noise over classical noise is 12 dB in the frequency band over 4 GHz, which is the best parameters of quantum-noise generators known from the literature.
PHYSICAL REVIEW APPLIED
(2022)
Review
Multidisciplinary Sciences
Michael Bordag
Summary: This article reviews the instabilities that arise from the coupling of spin-one fields to a magnetic background in a non-Abelian theory. The coupling contributes to the effective potential due to asymptotic freedom in a negative quantum. The Savvidy vacuum emerges in QCD, but its instability caused by the tachyonic mode leaves the true ground state of QCD still open. In the electroweak model, the corresponding instability is postponed to very large background fields and may be relevant in the early universe.
Article
Physics, Nuclear
M. Bordag
Summary: In this paper, the issue of chromomagnetic vacuum in SU(2) is studied, revealing a minimum below zero in the effective Lagrangian in the one-loop approximation, leading to the spontaneous generation of a magnetic field. However, this minimum is unstable due to the presence of an imaginary part in the effective action. Numerous attempts have been made to address this issue, all of which have been unsatisfactory to some extent. A new solution is proposed by considering the condensate formation of the tachyonic mode at low temperature, resulting in a phase transition similar to the Higgs model. The approximation with only the tachyonic mode and an O(2)-model with quartic self-interaction in two dimensions is considered. The CJT (2PI) formalism in Hartree approximation is applied, revealing a minimum of the effective action at a certain value of the condensate and background fields at zero and low temperatures, with no imaginary part. As the temperature increases, this minimum becomes shallower, and at a critical temperature, the perturbative state with lower effective potential becomes dominant, restoring the symmetry. The physically interpreted mechanism states that the unstable mode creates tachyons until they reach equilibrium through repulsive self-interactions and form a condensate. The relation to the Mermin-Wagner theorem is discussed.
EUROPEAN PHYSICAL JOURNAL A
(2023)
Review
Physics, Multidisciplinary
Galina L. Klimchitskaya, Vladimir M. Mostepanenko
Summary: This article reviews the scientific pictures of the universe from ancient times to Albert Einstein and highlights Alexander Friedmann's prediction of the universe expansion. It discusses the experimental confirmation of this prediction and the implications it has on our understanding of the world.
Article
Optics
E. E. Popov, A. A. Sergeev, A. P. Pogoda, V. M. Petrov, A. S. Boreisho
Summary: This study investigates the lasing spectra of a pulsed laser based on a Cr:LiSrAlF6 active medium, and demonstrates for the first time in Russia the simultaneous narrowband lasing at two aliquant wavelengths. Additionally, the continuous tuning of the central wavelength of the laser emission is achieved using a volume transmission Bragg grating.
JOURNAL OF OPTICAL TECHNOLOGY
(2022)
Review
Imaging Science & Photographic Technology
Viktor Petrov, Anastsiya Pogoda, Vladimir Sementin, Alexander Sevryugin, Egor Shalymov, Dmitrii Venediktov, Vladimir Venediktov
Summary: Holographic interferometry is a well-established field in science and optical engineering, with a long history of successful implementation in solving technical tasks and problems. Recent advancements in digital and computer holography have taken it to a new level, opening up new possibilities and applications.
JOURNAL OF IMAGING
(2022)
Article
Optics
N. D. Gerasimenko, V. S. Gerasimenko, V. M. Petrov
Summary: The electrical properties of traveling wave electrodes positioned on a lithium niobate surface were investigated in this study through analytical calculation, numerical modeling, and experimental investigation. The results showed that traveling wave electrodes with a refractive index close to the refractive index of the optical waveguide can effectively modulate the phase of light. This study has practical significance for the fabrication of integrated optical circuits.
JOURNAL OF OPTICAL TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
G. L. Klimchitskaya, V. M. Mostepanenko, O. Yu. Tsybin
Summary: In this study, the nonequilibrium Casimir-Polder force between a nanoparticle and a graphene sheet kept at different temperatures was examined using the formalism of the polarization tensor in the framework of a Dirac model. The results demonstrate that the magnitude of the force increases with the temperature of the graphene sheet. The impact of nonequilibrium conditions on the force becomes smaller at larger separations. Our findings reveal that for a graphene sheet with a lower temperature than the environment, the attractive Casimir-Polder force vanishes at a specific separation distance and becomes repulsive at larger distances. This effect has potential applications in fundamental graphene research and force control in bioelectronic microdevices.
Article
Physics, Particles & Fields
M. Bordag, V Skalozub
Summary: This paper investigates the behavior of the effective action or free energy in SU(2) gluodynamics at finite temperature, when both A(0) background and magnetic background are present. The results show that the imaginary part is still present at the two-loop level, and the real part exhibits an unnatural singularity in the region where the imaginary part sets in.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Optics
G. L. Klimchitskaya, V. M. Mostepanenko
Summary: The paper introduces a new phenomenological dielectric function for metals, which exhibits similar response as the standard Drude model for propagating waves but different response for evanescent waves. Using this function, the effective Casimir pressure and force between different test bodies are calculated and compared with measurement data. The results show that the predictions of the Lifshitz theory using the dissipative nonlocal response functions are in good agreement with the measurement data.
