International Journal of Physics | Vol. 6, No. 12, December 2015 | pp. 89–96
DOI: 10.46882/2015/IJP/000068
Research Article
Title: Optical Soliton Perturbations and Rogue Wave Formations in Non-Local Metamaterials with Power-Law Non-Linearities
Names of Authors: S. H. Zhang¹, E. C. Sterling²
Authors’ Affiliations: ¹Department of Physics, Tsinghua University, Beijing, China; ²Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
Abstract: Designing optical systems that can stabilize ultra-short laser pulses or safely mitigate high-power filamentation is crucial for advanced laser physics and deep-space data transmission networks. This paper solves the generalized non-linear Schrödinger equation governing optical soliton perturbations and models rogue wave formations within non-local metamaterials exhibiting a power-law non-linearity. The mathematical model includes higher-order perturbation terms, specifically third-order dispersion, self-steepening, and inter-file Raman scattering delays. We apply the inverse scattering transform method alongside a multiple-scale perturbation algorithm to derive analytical solutions for single-soliton and breathers. The results show that a high degree of spatial non-locality effectively suppresses collapse modes, stabilizing two-dimensional structures that are unstable in local Kerr media. The modulational instability growth rate was calculated as a function of perturbation frequency, revealing a maximum gain value of g = 2.84 cm^-1 under an input intensity of 1.8 kW/cm². Increasing the non-locality parameter from 0.8 mm to 4.0 mm reduces the maximum instability gain by 65.0% and shifts the peak gain toward longer perturbation wavelengths, preventing catastrophic pulse fragmentation.
Keywords: Nonlinear optics; spatial solitons; nonlinear Schrödinger equation; modulational instability; non-local media; split-step Fourier method
Manuscript Timeline: Received: August 18, 2015; Revised: October 10, 2015; Accepted: November 02, 2015; Published: December 16, 2015
Citation: Zhang, S. H., & Sterling, E. C. (2015). Optical Soliton Perturbations and Rogue Wave Formations in Non-Local Metamaterials with Power-Law Non-Linearities. International Journal of Physics, 6(12), 89–96.
International Journal of Physics | Vol. 6, No. 11, November 2015 | pp. 81–88
DOI: 10.46882/2015/IJP/000067
Research Article
Title: Superconducting Gap Structure and Spin Fluctuations in Electron-Doped Pnictide LaFeAsO0.85F0.15 Single Crystals
Names of Authors: I. R. Sokolov¹, B. J. Holford²
Authors’ Affiliations: ¹Kapitza Institute for Physical Problems, Russian Academy of Sciences, Moscow, Russia; ²Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
Abstract: Uncovering the exact pairing symmetry of iron-based pnictide superconductors remains a primary challenge in modern condensed matter physics. We synthesized high-quality single crystals of electron-doped LaFeAsO0.85F0.15 utilizing a high-pressure flux growth methodology at 4.5 GPa. The superconducting gap structure and spin fluctuations were evaluated through high-resolution angle-resolved photoemission spectroscopy and low-temperature London penetration depth measurements. The single crystals exhibited a sharp superconducting transition at Tc = 26.5 K with a magnetic susceptibility transition width of ΔT = 0.3 K. The temperature dependence of the London penetration depth shows an exponential behavior at low temperatures (T less than 0.3 Tc), which rules out the presence of line nodes in the order parameter. The photoemission spectra revealed two distinct, fully gapped isotropic superconducting bands. The larger gap value was measured at Δ1 = 7.2 meV on the inner hole-like Fermi surface sheet, while the smaller gap was found at Δ2 = 3.6 meV on the electron-like sheets. This gap configuration yields a strong-coupling ratio of 2Δ1/kBTc = 6.3, indicating strong-coupling superconductivity. These experimental results align with the s± pairing symmetry model driven by interband spin fluctuations.
Keywords: Iron-based superconductors; gap structure; angle-resolved photoemission spectroscopy; London penetration depth; pairing symmetry; spin fluctuations
Manuscript Timeline: Received: July 12, 2015; Revised: September 04, 2015; Accepted: September 22, 2015; Published: November 12, 2015
Citation: Sokolov, I. R., & Holford, B. J. (2015). Superconducting Gap Structure and Spin Fluctuations in Electron-Doped Pnictide LaFeAsO0.85F0.15 Single Crystals. International Journal of Physics, 6(11), 81–88.
International Journal of Physics | Vol. 6, No. 10, October 2015 | pp. 73–80
DOI: 10.46882/2015/IJP/000066
Research Article
Title: Squeezed Vacuum State Transport and Photonic Entanglement Dynamics in Disordered Optical Cavity Arrays
Names of Authors: A. M. Ross¹, F. Z. Al-Rawi²
Authors’ Affiliations: ¹Department of Physics, University of Queensland, Brisbane, QLD 4072, Australia; ²Department of Physics, Faculty of Science, University of Baghdad, Baghdad, Iraq
Abstract: Maintaining quantum state correlations across integrated optical networks is crucial for building fault-tolerant quantum computing architectures and secure communication lines. This paper models continuous-wave squeezed vacuum state transport and characterizes photonic entanglement dynamics within a linear array of coupled semiconductor microcavities subjected to spatial Anderson disorder. We solved the quantum stochastic Schrödinger equations using an algebraic operator framework that accounts for localized evanescent coupling variations, cavity mirror losses, and thermal phonon dephasing at 4.2 K. Squeezed vacuum states at 1064.0 nm were injected into the boundary cavity of a 20-channel system. The calculations demonstrate that introducing a 5.0% structural disorder in cavity resonance frequencies induces strong spatial localization of light. This localization reduces the squeezing level in the primary channel from 7.5 dB down to 2.1 dB over a brief 10.0 ps interaction window. To protect the quantum states, we simulated an active phase-modulation feedback sequence. This sequence establishes a synthetic gauge field that suppresses backscattering and locks the relative phase of the local oscillator. The optimized array configuration successfully restored the squeezing level to 6.4 dB at the output port, yielding a state fidelity calculation of 95.1% ± 0.3%.
Keywords: Quantum optics; squeezed states; optical cavities; Anderson localization; entanglement dynamics; integrated photonics
Manuscript Timeline: Received: June 04, 2015; Revised: July 28, 2015; Accepted: August 18, 2015; Published: October 14, 2015
Citation: Ross, A. M., & Al-Rawi, F. Z. (2015). Squeezed Vacuum State Transport and Photonic Entanglement Dynamics in Disordered Optical Cavity Arrays. International Journal of Physics, 6(10), 73–80.
International Journal of Physics | Vol. 6, No. 9, September 2015 | pp. 65–72
DOI: 10.46882/2015/IJP/000065
Research Article
Title: Finite Element Modeling of Acoustic Cloaking and Wave Redirection in Poroelastic Metamaterials
Names of Authors: P. J. O’Connor¹, H. J. Mueller²
Authors’ Affiliations: ¹Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland; ²Institute of Physics, Karlsruher Institut für Technologie, Karlsruhe, Germany
Abstract: Controlling acoustic paths in underwater and structural environments is essential for stealth technologies and specialized noise insulation. This study implements a finite element modeling approach to simulate acoustic cloaking and wave redirection within poroelastic acoustic metamaterials. The design leverages a coordinate-transformation method applied to Biot's dynamic poroelastic equations to determine the required anisotropic distribution of density and elastic moduli tensors. We performed numerical scattering simulations across an ultrasonic frequency band from 20.0 kHz to 100.0 kHz. The computational models show that a cylindrical cloak constructed with 24 concentric sub-wavelength layers successfully routes an incident acoustic wave around a rigid obstacle. This configuration reduces the total scattering cross-section by 84.0% at a design frequency of 50.0 kHz. We analyzed the impact of fluid viscosity on cloaking performance, finding that viscous dissipation in the porous channels dampens higher-order harmonic fields. This damping restricts forward transmission to a minor 4.2% energy loss. Experimental validation was carried out using 3D-printed perforated polyurethane matrices immersed in water. The measured pressure fields matched the simulated profiles within a ±5.0% margin. These results provide practical strategies for building underwater acoustic shields and high-performance sound absorbers.
Keywords: Acoustic metamaterials; finite element modeling; acoustic cloaking; Biot's theory; wave redirection; porous media
Manuscript Timeline: Received: May 12, 2015; Revised: July 03, 2015; Accepted: July 25, 2015; Published: September 11, 2015
Citation: O’Connor, P. J., & Mueller, H. J. (2015). Finite Element Modeling of Acoustic Cloaking and Wave Redirection in Poroelastic Metamaterials. International Journal of Physics, 6(9), 65–72.
International Journal of Physics | Vol. 6, No. 8, August 2015 | pp. 57–64
DOI: 10.46882/2015/IJP/000064
Research Article
Title: Fluid Inflow Velocity Mapping and Flare Dynamics in the Solar Atmosphere via High-Resolution Ultraviolet Spectroscopy
Names of Authors: G. R. Davies¹, A. L. Mendoza²
Authors’ Affiliations: ¹School of Physics and Astronomy, University of St Andrews, St Andrews, UK; ²Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
Abstract: Magnetic reconnection is the fundamental plasma driver behind explosive energy release events in the solar atmosphere, accelerating solar winds and triggering coronal mass ejections. This paper maps fluid inflow velocities and analyzes flare dynamics within a solar active region using high-resolution data from satellite ultraviolet spectrometers. We tracked the Doppler shifts and intensity profiles of the Si IV and Fe XXI spectral emission lines to isolate reconnection pathways. The empirical measurements reveal localized plasma inflows moving at 22.4 km/s, while directed outflows reach velocities of 310.0 km/s into the coronal loops. Based on these transport metrics, the local dimensionless reconnection rate was calculated to range between 0.06 and 0.09. These values closely align with fast reconnection regimes predicted by the Sweet-Parker theoretical framework modified by plasmoid instabilities. Spectroscopic line-broadening analysis indicates localized turbulent temperatures peaking at 12.5 MK within the current sheet boundary. This high temperature confirms intense localized viscous dissipation. These spectroscopic diagnostics provide direct observational constraints for refining magnetohydrodynamic models of solar coronal heating mechanisms.
Keywords: Solar atmosphere; magnetic reconnection; solar flares; ultraviolet spectroscopy; plasma velocity; magnetohydrodynamics
Manuscript Timeline: Received: April 15, 2015; Revised: June 02, 2015; Accepted: June 22, 2015; Published: August 19, 2015
Citation: Davies, G. R., & Mendoza, A. L. (2015). Fluid Inflow Velocity Mapping and Flare Dynamics in the Solar Atmosphere via High-Resolution Ultraviolet Spectroscopy. International Journal of Physics, 6(8), 57–64.
International Journal of Physics | Vol. 6, No. 7, July 2015 | pp. 49–56
DOI: 10.46882/2015/IJP/000063
Research Article
Title: Quantum Efficiency Optimization of Perovskite Solar Cells via Graded Bandgap Architecture
Names of Authors: H. K. Tanaka¹, C. M. Brauer²
Authors’ Affiliations: ¹Department of Quantum Engineering, Nagoya University, Nagoya, Japan; ²Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany
Abstract: Perovskite solar cells (PSCs) have emerged as highly promising candidates for low-cost, high-efficiency photovoltaics. This paper presents a detailed numerical model to optimize the internal quantum efficiency of methylammonium lead iodide (MAPbI3) perovskite solar cells using a graded bandgap architecture. We systematically evaluated the impacts of carrier recombination lifetimes and interface defect densities on device performance parameters under standard one-sun illumination (AM 1.5G, 100.0 mW/cm²). Our numerical calculations reveal that grading the iodine-to-bromine ratio creates a linear bandgap profile (varying from 1.55 eV to 1.80 eV), which generates a built-in electric field. This built-in field accelerates charge separation and reduces radiative recombination rates. When standard recombination lifetimes of 20.0 ns are introduced, the optimized graded device yields a short-circuit current density of 24.8 mA/cm² and an open-circuit voltage of 1.18 V. This results in a maximum power conversion efficiency of 23.4%, representing a significant improvement over the 18.2% efficiency calculated for the uniform bandgap control cell. We also analyzed the thermal stability of the device between 280.0 K and 360.0 K, demonstrating that the graded structure reduces thermal efficiency degradation by 30.0%. These insights provide practical guidelines for engineering high-performance perovskite photovoltaics.
Keywords: Perovskite solar cells; graded bandgap; quantum efficiency; charge transport; numerical modeling; photovoltaics
Manuscript Timeline: Received: March 20, 2015; Revised: May 05, 2015; Accepted: May 28, 2015; Published: July 15, 2015
Citation: Tanaka, H. K., & Brauer, C. M. (2015). Quantum Efficiency Optimization of Perovskite Solar Cells via Graded Bandgap Architecture. International Journal of Physics, 6(7), 49–56.