Influence of external magnetic field on high-harmonic generation upon propagation of an ultrashort optical airy pulse in a CNTs photonic crystal

2020 ◽  
pp. 2150017
Author(s):  
Y. V. Dvuzhilova ◽  
I. S. Dvuzhilov ◽  
N. N. Konobeeva ◽  
M. B. Belonenko
Keyword(s):  
Magnetic Field ◽  
Photonic Crystal ◽  
External Magnetic Field ◽  
Cross Section ◽  
Optical Pulse ◽  
High Harmonic ◽  
Three Dimensional ◽  
Ultrashort Optical Pulse ◽  
Limited Region ◽  
High Harmonics

In this paper, we consider the influence of magnetic pump field on the propagation of three-dimensional ultrashort optical pulse with Airy cross-section in a medium of a photonic crystal made of carbon nanotubes (CNTs). It is shown, that the pulse remains localized in a limited region of space and propagates quasi-stable. The possibility of efficient generation of high harmonics under the influence of an external magnetic field that were initially absent is observed.

Flow Visualization by Means of Contactless Inductive Flow Tomography in the Presence of a Magnetic Brake

2015 ◽  
Vol 15 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Matthias Ratajczak ◽  
Thomas Wondrak ◽  
Klaus Timmel ◽  
Frank Stefani ◽  
Sven Eckert
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Flow Field ◽  
Continuous Casting ◽  
Flow Structure ◽  
Cross Section ◽  
Two Dimensional ◽  
Slab Casting ◽  
Two Dimensional Flow

AbstractIn continuous casting DC magnetic fields perpendicular to the wide faces of the mold are used to control the flow in the mold. Especially in this case, even a rough knowledge of the flow structure in the mold would be highly desirable. The contactless inductive flow tomography (CIFT) allows to reconstruct the dominating two-dimensional flow structure in a slab casting mold by applying one external magnetic field and by measuring the flow-induced magnetic fields outside the mold. For a physical model of a mold with a cross section of 140 mm×35 mm we present preliminary measurements of the flow field in the mold in the presence of a magnetic brake. In addition, we show first reconstructions of the flow field in a mold with the cross section of 400 mm×100 mm demonstrating the upward scalability of CIFT.

scholarly journals Room temperature giant magnetostriction in single-crystal nickel nanowires

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasios Pateras ◽  
Ross Harder ◽  
Sohini Manna ◽  
Boris Kiefer ◽  
Richard L. Sandberg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Three Dimensional ◽  
Local Strain ◽  
Nickel Nanowires ◽  
Giant Magnetostriction

Abstract Magnetostriction is the emergence of a mechanical deformation induced by an external magnetic field. The conversion of magnetic energy into mechanical energy via magnetostriction at the nanoscale is the basis of many electromechanical systems such as sensors, transducers, actuators, and energy harvesters. However, cryogenic temperatures and large magnetic fields are often required to drive the magnetostriction in such systems, rendering this approach energetically inefficient and impractical for room-temperature device applications. Here, we report the experimental observation of giant magnetostriction in single-crystal nickel nanowires at room temperature. We determined the average values of the magnetostrictive constants of a Ni nanowire from the shifts of the measured diffraction patterns using the 002 and 111 Bragg reflections. At an applied magnetic field of 600 Oe, the magnetostrictive constants have values of λ100 = −0.161% and λ111 = −0.067%, two orders of magnitude larger than those in bulk nickel. Using Bragg coherent diffraction imaging (BCDI), we obtained the three-dimensional strain distribution inside the Ni nanowire, revealing nucleation of local strain fields at two different values of the external magnetic field. Our analysis indicates that the enhancement of the magnetostriction coefficients is mainly due to the increases in the shape, surface-induced, and stress-induced anisotropies, which facilitate magnetization along the nanowire axis and increase the total magnetoelastic energy of the system.

An improved scheme for the calculation of NMR chemical shifts in periodic systems based on gauge including atomic orbitals and density functional theory

2011 ◽  
Vol 89 (9) ◽  
pp. 1150-1161 ◽  
Author(s):  
Dmitry Skachkov ◽  
Mykhaylo Krykunov ◽  
Tom Ziegler
Keyword(s):  
Magnetic Field ◽  
Density Functional Theory ◽  
External Magnetic Field ◽  
Density Functional ◽  
Three Dimensional ◽  
Nuclear Magnetic Moment ◽  
Zero Order ◽  
Periodic Systems ◽  
Functional Theory ◽  
Atomic Orbitals

We report here on an improved first principles method that can determine NMR shielding tensors for periodic systems. Our scheme evaluates the shielding tensor as the second derivative of the total electronic energy with respect to a nuclear magnetic moment and an external magnetic field. Both the induced current density J(α) due to the first perturbation from the nuclear magnetic moment as well as the interaction of J(α) with the second perturbation in the form of an external magnetic field are evaluated analytically. Our approach is based on Kohn–Sham density functional theory and gauge-including atomic orbitals. It employs a Bloch basis set made up of Slater-type or numeric atomic orbitals and represents the Kohn–Sham potential fully without the use of effective core potentials. The method is implemented into the periodic program BAND. The new scheme represents an improvement over a previously proposed method in that use can be made of the zero-order Kohn–Sham orbitals from a calculation based on a primitive cell instead of a supercell. Further, J(α) is evaluated analytically rather than by a finite difference approach. The improvements reduce the required computational time by up to two orders of magnitude for three-dimensional systems. Such a reduction is made possible by the fact that we are using atomic centered basis functions. The new implementation is further able to take into account scalar relativistic effects within the zero-order regular approximation. Results from calculations of NMR shielding constants based on the present approach are presented for systems with one-, two-, and three-dimensional periodicity. The reported values are compared to experiment and results from the previously proposed scheme.

Exploration of the Structures of the Magnetically Induced Self-Assembly Photonic Crystals in a Solidified Polymer Matrix

2013 ◽  
Vol 634-638 ◽  
pp. 2324-2331
Author(s):  
Hai Bo Hu ◽  
Qian Wang Chen ◽  
Ran Li ◽  
Xiang Kai Kong ◽  
Jian Chen
Keyword(s):  
Magnetic Field ◽  
Photonic Crystal ◽  
External Magnetic Field ◽  
Crystal Structures ◽  
Polymer Matrix ◽  
Self Assembly ◽  
Large Scale ◽  
Solid Polymer ◽  
One Dimension ◽  
Polyacrylamide Hydrogel

The carbon-encapsulated superparamagnetic colloidal nanoparticles (SCNps) were rigidized into soft solids by embedding the SCNps into polyacrylamide hydrogel matrixes under the induction of an external magnetic field. Stabilized by the balance of attractive (magnetic) and repulsive (electrostatic) forces, the SCNps form one-dimension photonic crystal structures along the direction of the external magnetic field and further the structures are frozen into the solidified polymer matrix. The polymer matrix embedded one-dimension photonic crystal structures can strongly diffract visible light and present brilliant color in the light. This novel and soft solid polymer matrix that could be shaped and sliced not only paves a new avenue for develop novel magnetic-responsive photonic crystal materials and devices, but also provides a method to observe the magnetic-induced self-assembly structures of the SCNps in media such as polyacrylamide hydrogel matrixs as a result of the ordered structures frozen into the polyacrylamide hydrogel matrixs. So we can reveal the relationship between their structure and color, and furthermore permit a systematic exploration on magnetically induced self-assembling dynamics, colloidal crystallography which have important significance in the large-scale industrial production in the future.

scholarly journals Влияние магнитного поля на термодинамические и магнитные свойства антиферромагнитной модели Изинга на объемно-центрированной кубической решетке

2020 ◽  
Vol 62 (2) ◽  
pp. 229
Author(s):  
А.К. Муртазаев ◽  
М.К. Рамазанов ◽  
К.Ш. Муртазаев ◽  
М.А. Магомедов ◽  
М.К. Бадиев
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Three Dimensional ◽  
Nearest Neighbors ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
The Monte Carlo Method ◽  
Body Centered Cubic Lattice ◽  
Second Order Phase Transition

The influence of the external magnetic field on the phase transitions, thermodynamic and magnetic properties of the three-dimensional Ising model of antiferromagnetic on a body-centered cubic lattice taking into account the interactions of the second nearest neighbors is studied by the replica algorithm of the Monte Carlo method. A phase diagram of the dependence of the critical temperature on the external magnetic field has been constructed. It is shown that a second-order phase transition is observed in the considered range of magnetic field values

scholarly journals A Method of the Riemann–Hilbert Problem for Zhang’s Conjecture 2 in a Ferromagnetic 3D Ising Model: Topological Phases

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2936
Author(s):  
Zhidong Zhang ◽  
Osamu Suzuki
Keyword(s):  
Magnetic Field ◽  
Ising Model ◽  
External Magnetic Field ◽  
Hilbert Problem ◽  
Three Dimensional ◽  
Preceding Paper ◽  
Mathematical Structure ◽  
Topological Phases ◽  
Riemann Hilbert Problem ◽  
3D Ising Model

A method of the Riemann–Hilbert problem is employed for Zhang’s conjecture 2 proposed in Philo. Mag. 87 (2007) 5309 for a ferromagnetic three-dimensional (3D) Ising model in a zero external magnetic field. In this work, we first prove that the 3D Ising model in the zero external magnetic field can be mapped to either a (3 + 1)-dimensional ((3 + 1)D) Ising spin lattice or a trivialized topological structure in the (3 + 1)D or four-dimensional (4D) space (Theorem 1). Following the procedures of realizing the representation of knots on the Riemann surface and formulating the Riemann–Hilbert problem in our preceding paper [O. Suzuki and Z.D. Zhang, Mathematics 9 (2021) 776], we introduce vertex operators of knot types and a flat vector bundle for the ferromagnetic 3D Ising model (Theorems 2 and 3). By applying the monoidal transforms to trivialize the knots/links in a 4D Riemann manifold and obtain new trivial knots, we proceed to renormalize the ferromagnetic 3D Ising model in the zero external magnetic field by use of the derivation of Gauss–Bonnet–Chern formula (Theorem 4). The ferromagnetic 3D Ising model with nontrivial topological structures can be realized as a trivial model on a nontrivial topological manifold. The topological phases generalized on wavevectors are determined by the Gauss–Bonnet–Chern formula, in consideration of the mathematical structure of the 3D Ising model. Hence we prove the Zhang’s conjecture 2 (main theorem). Finally, we utilize the ferromagnetic 3D Ising model as a platform for describing a sensible interplay between the physical properties of many-body interacting systems, algebra, topology, and geometry.

scholarly journals Световые пули с бесселевым поперечным сечением в среде углеродных нанотрубок

2022 ◽  
Vol 130 (3) ◽  
pp. 407
Author(s):  
А.М. Белоненко ◽  
И.С. Двужилов ◽  
Ю.В. Двужилова ◽  
М.Б. Белоненко
Keyword(s):  
Carbon Nanotubes ◽  
Key Words ◽  
Cross Section ◽  
Nonlinear Medium ◽  
Three Dimensional ◽  
Optical Pulses ◽  
Limited Region ◽  
Conservation Of Energy ◽  
Light Bullets ◽  
Extremely Short Optical Pulses

The propagation of three-dimensional extremely short optical pulses (light bullets) with a Bessel cross section in a medium of carbon nanotubes placed in an optical resonator is considered. As a result of numerical calculations, it was found that such pulses propagate stably with conservation of energy in a limited region of space, including at large times of the order of 100 ps. Key words: extremely short optical pulses, nonlinear medium, light bullets, carbon nanotubes.

3D few cycle optical pulses in carbon nanotube-based photonic crystal with allowance for mechanical stress

2021 ◽  
pp. 2150435
Author(s):  
Yu. V. Dvuzhilova ◽  
I. S. Dvuzhilov ◽  
M. B. Belonenko ◽  
E. N. Galkina
Keyword(s):  
Refractive Index ◽  
Carbon Nanotube ◽  
Gauge Theory ◽  
Photonic Crystal ◽  
Theoretical Model ◽  
Mechanical Stress ◽  
Optical Pulse ◽  
Three Dimensional ◽  
Optical Pulses ◽  
Pulse Dynamics

This paper constructs and numerically analyzes a theoretical model of three-dimensional few cycle optical pulse dynamics in semiconductor carbon nanotube-based spatially-modulated refractive index medium. It takes into account external deformation in terms of the gauge theory. It identifies the stable propagation of that kind of pulses in photonic crystal. The paper also reveals the dependence of pulse dynamics on photonic crystal characteristics (refractive index depth and modulation period in particular).

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