International Journal of Physics

International Journal of Physics | Vol. 12, No. 12, December 2021 | pp. 89–96

DOI: 10.46882/2021/IJP/000140

Research Article

Title: Finite Element Modeling of Acoustic Cloaking and Spatial Wave Redirection in Porous Piezoceramic Lattices

Names of Authors: P. J. O’Connor¹, V. I. Morozov²

Authors’ Affiliations:
¹ Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland
² Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia

Abstract: Deflecting acoustic wave pathways inside fluid-saturated structural arrays is essential for developing underwater sonar hiding cloaks, advanced noise barriers, and targeted seismic protection matrices. This study implements a finite element modeling approach to simulate acoustic cloaking and spatial wave redirection patterns within a porous piezoceramic metamaterial lattice. The design utilizes coordinate-transformation mathematics applied directly to Biot's dynamic poroelastic equations to compute the necessary anisotropic distribution of density and elastic moduli tensors across the shell. We conducted numerical scattering simulations over an ultrasonic frequency spectrum from 20.0 kHz to 120.0 kHz. The computational models show that a cylindrical cloak constructed with 32 concentric sub-wavelength layers successfully guides an incident sound wave around a hidden cavity segment. This active system decreases the total acoustic scattering cross-section by 85.0% at a design marker of 60.0 kHz. We analyzed the impact of electrical boundary loads, demonstrating that adaptive capacitive shunting paths actively tune the effective bulk modulus tensor under changing fluid pressures. Experimental testing was performed using 3D-printed perforated barium titanate components in water, matching simulated data within a ±5.2% margin.

Keywords: Acoustic metamaterials; finite element modeling; acoustic cloaking; Biot's theory; piezoceramics; wave redirection

Manuscript Timeline: Received: August 18, 2021; Revised: October 10, 2021; Accepted: November 02, 2021; Published: December 16, 2021

Citation: O’Connor, P. J., & V. I. Morozov. (2021). Finite Element Modeling of Acoustic Cloaking and Spatial Wave Redirection in Porous Piezoceramic Lattices. International Journal of Physics, 12(12), 89–96.

International Journal of Physics | Vol. 12, No. 11, November 2021 | pp. 81–88

DOI: 10.46882/2021/IJP/000139

Research Article

Title: Fluid Velocity Mapping and Reconnection Flux Rates in Solar Flare Ribbons via Space Spectrometers

Names of Authors: G. R. Davies¹, A. M. El-Chemali²

Authors’ Affiliations:
¹ School of Physics and Astronomy, University of St Andrews, St Andrews, UK
² Department of Physics, Faculty of Science, Lebanese University, Beirut, Lebanon

Abstract: High-energy magnetic reconnection is the primary magnetohydrodynamic mechanism that drives rapid energy conversion paths in the solar corona, heating plasma to millions of Kelvin and propelling solar flare ribbons. This paper models fluid velocity fields and quantifies localized magnetic reconnection flux rates within an active region solar flare event. We utilized high-resolution spectroscopic data from space-based solar trackers measuring extreme ultraviolet emission lines from highly ionized iron states (Fe XII and Fe XXIV). Differential affine velocity estimator algorithms were deployed to compile two-dimensional transport fields of plasma inflows and outflows flanking the dissipation current sheet. The empirical measurements reveal systematic plasma inflows moving at 15.6 km/s, while directed shock outflows achieve velocities of 320.0 km/s along the magnetic loop headers. 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 limits predicted by the Petschek framework modified by local tearing instabilities. Spectroscopic line-broadening analysis indicates localized turbulent temperatures peaking at 11.2 MK within the current layer boundary, verifying strong viscous dissipation.

Keywords: Solar corona; magnetic reconnection; extreme ultraviolet; plasma velocity; solar flares; magnetohydrodynamics

Manuscript Timeline: Received: July 12, 2021; Revised: September 04, 2021; Accepted: September 22, 2021; Published: November 12, 2021

Citation: Davies, G. R., & El-Chemali, A. M. (2021). Fluid Velocity Mapping and Reconnection Flux Rates in Solar Flare Ribbons via Space Spectrometers. International Journal of Physics, 12(11), 81–88.

International Journal of Physics | Vol. 12, No. 10, October 2021 | pp. 73–80

DOI: 10.46882/2021/IJP/000138

Research Article

Title: Optical Properties and Exciton Dynamics of Monolayer Tungsten Diselenide on Silicon Oxide Slot Waveguides

Names of Authors: Y. S. Kim¹, T. H. Nguyen²

Authors’ Affiliations:
¹ Department of Physics and Astronomy, Seoul National University, Seoul, South Korea
² Department of Physics, Vietnam National University, Hanoi, Vietnam

Abstract: Layered transition metal dichalcogenides have attracted significant industrial interest due to their strong light-matter couplings and potential for building chip-scale integrated optoelectronic platforms. This study characterises the optical properties and exciton dynamics of monolayer tungsten diselenide (WSe²) integrated onto silicon oxide slot waveguides. The monolayer flakes were synthesized via chemical vapor deposition and transferred onto the wave-guiding cores using an optimized dry-transfer technique. We performed micro-photoluminescence and angle-resolved reflectivity measurements under mechanical tensile strains from 0.0% to 1.6% at a room temperature of 300 K. The unstrained monolayer coupled to the slot waveguide area exhibits strong absorption lines, confirming efficient evanescent field capture. Applying a 1.0% tensile strain shifts the exciton resonance energy from 1.65 eV to 1.59 eV, yielding a strain tuning factor of 60.0 meV/% strain. Time-resolved photoluminescence spectroscopy revealed a shortened polariton decay lifetime, dropping from 16.5 ps down to 5.2 ps due to the dielectric slot Purcell effect. Our numerical models confirm that the tight localized electromagnetic field confinement within the slot increases the exciton-photon coupling rate by 35.0%. These findings demonstrate that slot-integrated strain architectures provide an effective path for tuning light-emitting states.

Keywords: Tungsten diselenide; slot waveguides; photoluminescence; exciton dynamics; tensile strain; integrated optics

Manuscript Timeline: Received: June 02, 2021; Revised: July 29, 2021; Accepted: August 25, 2021; Published: October 08, 2021

Citation: Kim, Y. S., & Nguyen, T. H. (2021). Optical Properties and Exciton Dynamics of Monolayer Tungsten Diselenide on Silicon Oxide Slot Waveguides. International Journal of Physics, 12(10), 73–80.

International Journal of Physics | Vol. 12, No. 9, September 2021 | pp. 65–72

DOI: 10.46882/2021/IJP/000137

Research Article

Title: Optical Soliton Perturbations and Rogue Wave Mitigation in Non-Local Graphene-Oxide Metamaterials

Names of Authors: S. H. Zhang¹, P. L. Becker²

Authors’ Affiliations:
¹ Department of Physics, Tsinghua University, Beijing, China
² Institute for Plasma Research, University of Stuttgart, Stuttgart, Germany

Abstract: Constructing nanoscale wave-guiding systems that can protect ultra-short laser signals or actively mitigate high-power optical rogue waves is a vital asset for advanced quantum telecommunication links. This paper solves the generalized non-linear Schrödinger equation governing optical soliton perturbations and tracks rogue wave formation profiles within non-local graphene-oxide metamaterials exhibiting power-law saturable non-linearities. The mathematical model integrates higher-order perturbation terms, including third-order dispersion, self-steepening, and inter-file Raman scattering delays. We apply the inverse scattering transform method paired with a multiple-scale perturbation algorithm to derive analytical solutions for single-soliton structures and breathers. The results prove that a high degree of spatial non-locality effectively arrests catastrophic self-focusing collapse, stabilizing two-dimensional structures that are unstable in local Kerr systems. 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 beam intensity of 1.8 kW/cm². Increasing the non-locality parameter from 0.8 mm to 4.2 mm reduces the maximum instability gain by 66.0% and shifts the peak gain toward longer perturbation wavelengths, avoiding pulse fragmentation.

Keywords: Nonlinear optics; spatial solitons; nonlinear Schrödinger equation; modulational instability; non-local media; rogue waves

Manuscript Timeline: Received: May 14, 2021; Revised: July 08, 2021; Accepted: August 03, 2021; Published: September 10, 2021

Citation: Zhang, S. H., & Becker, P. L. (2021). Optical Soliton Perturbations and Rogue Wave Mitigation in Non-Local Graphene-Oxide Metamaterials. International Journal of Physics, 12(9), 65–72.

International Journal of Physics | Vol. 12, No. 8, August 2021 | pp. 57–64

DOI: 10.46882/2021/IJP/000136

Research Article

Title: Superconducting Gap Structures and Interband Fluctuations in Electron-Doped Pnictide Ca0.85La0.15Fe2As2 Single Crystals

Names of Authors: I. R. Sokolov¹, A. A. Menshikov²

Authors’ Affiliations:
¹ Kapitza Institute for Physical Problems, Russian Academy of Sciences, Moscow, Russia
² Institute for Solid State Physics, Russian Academy of Sciences, Chernogolovka, Russia

Abstract: Identifying the exact pairing symmetries of iron-based pnictide materials is a principal research objective for expanding high-temperature superconducting models and electronic layouts. We synthesized high-quality single crystals of electron-doped Ca0.85La0.15Fe2As2 utilizing a high-pressure flux growth methodology executed at 4.8 GPa. The internal superconducting gap structures and localized 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 = 32.5 K with an narrow magnetic susceptibility transition width of ΔT = 0.3 K. The temperature dependence of the London penetration depth shows a distinct exponential behavior at low thresholds (T less than 0.3 Tc), which rules out the presence of line nodes in the order parameter. The photoemission spectra mapped out two separate, fully gapped isotropic superconducting bands across the Fermi surface. The larger gap value was measured at Δ1 = 8.4 meV on the inner hole-like sheet, while the smaller gap was found at Δ2 = 4.2 meV on the outer electron-like sheets. This gap configuration yields a strong-coupling ratio of 2Δ1/kBTc = 6.0, confirming an s± pairing symmetry model driven by interband spin fluctuations.

Keywords: Iron-based superconductors; gap structures; photoemission spectroscopy; London penetration depth; pairing symmetry; spin fluctuations

Manuscript Timeline: Received: April 05, 2021; Revised: June 01, 2021; Accepted: June 28, 2021; Published: August 16, 2021

Citation: Sokolov, I. R., & Menshikov, A. A. (2021). Superconducting Gap Structures and Interband Fluctuations in Electron-Doped Pnictide Ca0.85La0.15Fe2As2 Single Crystals. International Journal of Physics, 12(8), 57–64.

International Journal of Physics | Vol. 12, No. 7, July 2021 | pp. 49–56

DOI: 10.46882/2021/IJP/000135

Research Article

Title: Squeezed Vacuum State Propagation and Optomechanical Quantum Transduction in Photonic Crystal Cavities

Names of Authors: A. M. Ross¹, M. G. Richter²

Authors’ Affiliations:
¹ Department of Physics, University of Queensland, Brisbane, QLD 4072, Australia
² Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany

Abstract: High-fidelity optical-to-microwave conversion of non-classical light states is a primary requirement for building distributed quantum networks and linking distant superconducting quantum computers. This paper models continuous-wave squeezed vacuum state propagation and characterises optomechanical transduction dynamics within a silicon photonic crystal defect cavity. We solved the quantum stochastic Heisenberg-Langevin equations using an algebraic operator framework that accounts for localized optomechanical coupling paths, cavity mirror leaks, and thermal phonon dephasing at 4.2 K. Squeezed vacuum states at 1550.0 nm were injected into the boundary waveguide channel of a co-localized acoustic resonator network. The calculations demonstrate that introducing a minor 3.0% fabrication asymmetry across the mirror hole segments shifts the local cavity resonance, dropping the input squeezing level from 8.5 dB down to 2.2 dB due to destructive interference. To shelter the non-classical light from decay channels, we simulated an active phase-modulation feedback sequence that creates a synthetic gauge field to lock the relative phase parameters of the local oscillator. The optimized cavity layout successfully restored the squeezing level to 6.8 dB at the output port, yielding a target state fidelity calculation of 94.8% ± 0.3%.

Keywords: Quantum optics; squeezed states; photonic crystals; optomechanics; quantum transduction; integrated photonics

Manuscript Timeline: Received: March 11, 2021; Revised: May 19, 2021; Accepted: June 11, 2021; Published: July 12, 2021

Citation: Ross, A. M., & Richter, M. G. (2021). Squeezed Vacuum State Propagation and Optomechanical Quantum Transduction in Photonic Crystal Cavities. International Journal of Physics, 12(7), 49–56