A5103057061- Physics of Superconductivity and Magnetism
- Nonlinear Dynamics and Pattern Formation
- Nonlinear Photonic Systems
- Chaos control and synchronization
- Numerical Methods and Algorithms
- Magneto-Optical Properties and Applications
- Computational Physics and Python Applications
- Ion-surface interactions and analysis
- Aluminum Alloy Microstructure Properties
- Chaos-based Image/Signal Encryption
- Quantum and electron transport phenomena
- Laser-Ablation Synthesis of Nanoparticles
- Advanced Electrical Measurement Techniques
- Metallurgy and Material Forming
- Solidification and crystal growth phenomena
- Nonlinear Waves and Solitons
- nanoparticles nucleation surface interactions
- Microstructure and mechanical properties
- Advanced Condensed Matter Physics
- Quantum optics and atomic interactions
- Surface and Thin Film Phenomena
- Differential Equations and Numerical Methods
- Matrix Theory and Algorithms
- Mechanical and Optical Resonators
- Nuclear Materials and Properties
Sofia University "St. Kliment Ohridski"
2011-2023
OpenMP parallelization of multiple precision Taylor series method is proposed. A very good parallel performance scalability and efficiency inside one computation node a CPU-cluster observed. We explain the details on classical example Lorentz equations. The same approach can be applied straightforwardly to large class chaotic dynamical systems.
One of the promising areas in condensed matter physics is study interaction nanoclusters with various metallic targets. In this paper we investigate thermal processes metals irradiated by molecular dynamics method. framework method wave effects heat transfer are obtained, a feature which absent spike model. We repost results computer simulation structural changes copper targets different sizes depending on energy (in range 10–50 eV/atom) nanoclusters.
In this work we propose an efficient parallelization of multiple-precision Taylor series method with variable stepsize and fixed order. For given level accuracy the optimal determines higher order than in case stepsize. Although used is greater then that stepsize, hence computational per step greater, reduced number steps gives less overall work. Also beneficial sense it increases parallel efficiency. As a model problem use paradigmatic Lorenz system. With 256 CPU cores Nestum cluster,...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation I. Hristov, S. Dimova, T. Boyadjiev; Numerical Investigation of Josephson Junction Structures. AIP Conf. Proc. 29 October 2009; 1186 (1): 57–68. https://doi.org/10.1063/1.3265362 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search...
Over the last several decades active research in field of materials irradiation by high-energy heavy ions has been worked out. The experiments this area are labor-consuming and expensive. Therefore improvement existing mathematical models development new ones based on experimental data interaction with interest. Presently, two approaches used for studying these processes: a thermal spike model molecular dynamics methods. combination – continuous-atomistic will give opportunity to investigate...
A hybrid MPI+OpenMP strategy for parallelizing multiple precision Taylor series method is proposed, realized and tested. To parallelize the algorithm we combine MPI OpenMP parallel technologies together with GMP library (GNU miltiple libary) tiny MPIGMP library. The details of parallelization are explained on paradigmatic model Lorenz system. We succeed to obtain a correct reference solution in rather long time interval - [0,7000]. verified by comparing results 2700-th order ~ 3374 decimal...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation I. Hristov, S. Dimova, R. Hristova; The in-phase states of Josephson junctions stacks as attractors. AIP Conf. Proc. 12 November 2014; 1629 (1): 154–161. https://doi.org/10.1063/1.4902269 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar...
Starting with zero initial conditions we simulate the current-voltage characteristics (CVCs) of Intrinsic Josephson Junctions (IJJ) for parameters close to that BSCCO mesas. The simulation shows a regular pattern voltage jumps at voltages satisfying cavity resonance conditions. calculated emission has peaks every jump. Analyzing phases observe two-dimensional standing wave kink configuration as their static part. Depending on and bias current, amplitudes may differ from $\pi$ . By means Fast...
We study numerically the dynamics of multistacked Josephson junctions using unified model Machida and Sakai. This takes into account simultaneously inductive capacitive coupling between junctions. The influence on fluxon is analyzed a comparison with case only made. corresponding system perturbed sine-Gordon equations solved by finite difference methods. Different physical quantities that can be measured in real experiments are calculated.
The existence of stable coherent motions in different physical systems is a problem that attracts much attention the last years. We study numerically possibility (bunched) motion fluxons allocated at tunnel barriers N‐layered (N > 3) long Josephson stacks linear (open ends) geometry to exist absence external magnetic field. stability such configurations analyzed. It shown system bunched reflects from ends junctions without being destroyed. influence number stacked on investigated....
The paper is an overview of the main contributions a Bulgarian team researchers to problem finding possible structures and waves in open nonlinear heat conducting medium, described by reaction-diffusion equation. Being posed actively worked out Russian school A. Samarskii S.P. Kurdyumov since seventies last century, this still contains challenging questions.
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation I. Hristov, S. Dimova; Numerical study of fluxon lattices in long Josephson stacks. AIP Conference Proceedings 2 October 2012; 1487 (1): 377–385. https://doi.org/10.1063/1.4758981 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search...
When nanoclusters irradiate a metal target large amount of energy is realized in small volume which leads to structural changes metal. These can be consequence thermal processes or elastic repulsions atoms. The experimental studies fixe the results these target. application methods mathematical modeling allows "see" dynamics irradiation process, including and changes. Therefore, remains an important tool for such studies. One metals irradiated by method molecular dynamics.
Obtaining a long term reference trajectory on the chaotic attractor for coupled Lorenz system is adifficult task, due to sensitive dependence initial conditions. Using standard doubleprecision floating point arithmetic, we cannot obtain solution longer than 2.5 time units.Combining OpenMP parallel technology together with GMP library (GNU multiple precision library),we parallelize Taylor series algorithm and referencesolution in rather interval - [0,400]. We performed two large computations,...