International Journal of Physics | Vol. 15, No. 12, December 2024 | pp. 89–96
DOI: 10.46882/2024/IJP/000176
Research Article
Title: Relativistic Hydrodynamic Simulations of Directed Flow Instabilities in Asymmetric Germanium-Gold Collisions
Names of Authors: S. C. O’Brien¹, A. M. El-Chemali²
Authors’ Affiliations:
¹ School of Physics, University College Dublin, Dublin, Ireland
² Department of Physics, Faculty of Science, Lebanese University, Beirut, Lebanon
Abstract: High-energy asymmetric nuclear collisions provide an exceptional experimental platform to probe initial-state spatial geometry fluctuations and check the minimum boundary limits required to form a transient droplet of quark-gluon plasma. This study presents a relativistic hydrodynamic simulation framework to model particle production cascades and evaluate directed flow instabilities in germanium-gold (Ge-Au) collisions at a center-of-mass energy of 200.0 GeV per nucleon pair. We utilized a 3+1 dimensional viscous hydrodynamic code coupled with a statistical hadronization module to calculate final-state transverse momentum spectra. The initial energy density distributions were generated via a Monte Carlo Glauber model to track sub-nucleon scale configurations. The numerical simulations show that expanding fireballs develop a substantial radial flow profile, shifting the mean transverse momentum of protons up to 1.18 GeV/c in central events. The calculated directed flow coefficient (v1) displays a strong mass-ordering signature, which matches experimental tracking data from specialized heavy-ion detectors within a tight ±5.5% margin. This agreement implies that small-scale asymmetric nuclear interaction zones can briefly sustain fluid-like collective expansion profiles. These findings clarify the boundary constraints of fluid behavior in high-energy physics.
Keywords: Relativistic hydrodynamics; quark-gluon plasma; directed flow; asymmetric collisions; Glauber model; statistical hadronization
Manuscript Timeline: Received: September 15, 2024; Revised: October 30, 2024; Accepted: November 15, 2024; Published: December 16, 2024
Citation: O’Brien, S. C., & El-Chemali, A. M. (2024). Relativistic Hydrodynamic Simulations of Directed Flow Instabilities in Asymmetric Germanium-Gold Collisions. International Journal of Physics, 15(12), 89–96.
International Journal of Physics | Vol. 15, No. 11, November 2024 | pp. 81–88
DOI: 10.46882/2024/IJP/000175
Research Article
Title: Kinetic Modelling of Electron Swarm Fluxes and Dissociation Barriers in Propane-Oxygen Discharges
Names of Authors: D. L. Santos¹, T. H. Nguyen²
Authors’ Affiliations:
¹ Department of Physics, University of Coimbra, Coimbra, Portugal
² Department of Physics, Vietnam National University, Hanoi, Vietnam
Abstract: Propane-oxygen (C³H⁸-O2) gas discharges are widely deployed across the industrial materials processing and environmental chemical manufacturing sectors for synthetic carbon film growth, surface polymer activation, and volatile organic compound mitigation. This paper develops a self-consistent kinetic model to evaluate electron swarm fluxes and calculate molecular dissociation barriers in low-pressure propane-oxygen mixtures. We solved the electron Boltzmann equation using a multi-term spherical harmonic expansion framework across a wide reduced electric field range (E/N) from 10.0 Td to 500.0 Td. The cross-section dataset accounted for elastic momentum transfer, rotational transitions, vibrational excitation states, dissociative electron attachment, and direct impact ionization processes. Our modeling results show that adding small fractions of oxygen (from 5.0% to 20.0% by volume) significantly distorts the high-energy tail of the electron distribution function. At E/N = 85.0 Td, the total propyl radical (C³H⁷) production rate coefficient increases by over an order of magnitude due to efficient energy channeling into the primary vibrational thresholds of propane. The calculated electron drift velocities match independent swarm experimental measurements within a ±5.0% variance index. These kinetic parameters provide critical baseline inputs for optimizing commercial plasma reactors.
Keywords: Propane plasmas; Boltzmann equation; electron transport; dissociation barriers; chemical vapor deposition; cross-section
Manuscript Timeline: Received: August 18, 2024; Revised: October 10, 2024; Accepted: October 28, 2024; Published: November 12, 2024
Citation: Santos, D. L., & Nguyen, T. H. (2024). Kinetic Modelling of Electron Swarm Fluxes and Dissociation Barriers in Propane-Oxygen Discharges. International Journal of Physics, 15(11), 81–88.
International Journal of Physics | Vol. 15, No. 10, October 2024 | pp. 73–80
DOI: 10.46882/2024/IJP/000174
Research Article
Title: Topological Valley States and Spin-Polarized Edge Transport in lodinated Stanene Honeycomb Lattices
Names of Authors: J. W. Park¹, A. L. Silva²
Authors’ Affiliations:
¹ Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
² Institute of Physics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
Abstract: Valleytronics provides an alternative pathway for low-power electronic hardware architectures by leveraging the valley degree of freedom to lock charge transport channels. This study models topological valley states and characterises spin-polarized edge transport in two-dimensional honeycombed lattices of iodinated tin (stanene) films. We executed electronic band calculations using the relativistic tight-binding method across the hexagonal Brillouin zone. The combination of structural inversion asymmetry and strong intrinsic spin-orbit coupling breaks the valley degeneracy, opening a wide topological bulk bandgap of 0.22 eV. The system exhibits a non-zero valley Chern number of Cv = +1, which confirms non-trivial topological valley properties. To evaluate transport robustness, we simulated electron wavepacket propagation past point vacancies and sharp 60-degree boundary folds. The valley-polarized edge mode bypassed these structural obstacles with a high transmission efficiency of 99.4% ± 0.2%, demonstrating an absence of backscattering due to valley-contrast conservation rules. These findings provide solid engineering guidelines for building backscattering-immune valley-filter switches, quantum pathways, and integrated low-dissipation logic networks.
Keywords: Valleytronics; topological insulators; spin-orbit coupling; tight-binding method; edge states; stanene films
Manuscript Timeline: Received: July 12, 2024; Revised: September 04, 2024; Accepted: September 22, 2024; Published: October 14, 2024
Citation: Park, J. W., & Silva, A. L. (2024). Topological Valley States and Spin-Polarized Edge Transport in lodinated Stanene Honeycomb Lattices. International Journal of Physics, 15(10), 73–80.
International Journal of Physics | Vol. 15, No. 2, September 2024 | pp. 65–72
DOI: 10.46882/2024/IJP/000173
Research Article
Title: Elasticity Profiles and High-Pressure Structural Transformations in Ultra-Incompressible Molybdenum Disilicide Polytypes
Names of Authors: V. I. Morozov¹, P. J. O’Connor²
Authors’ Affiliations:
¹ Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia
² Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland
Abstract: Evaluating ultra-incompressible structural alloys capable of maintaining structural stability under immense mechanical loading parameters is vital for industrial abrasive design and high-pressure geoscience anvil instrumentation. This paper investigates high-pressure elasticity profiles and monitors structural phase transformations in hexagonal and tetragonal molybdenum disilicide (MoSi2) polytypes up to hydrostatic pressures of 160.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework across compressed atomic configurations. At zero pressure, the calculated bulk modulus is B0 = 218.0 GPa, with an elastic pressure derivative value of B0' = 4.05, matching experimental diamond anvil cell measurements within a 1.2% margin. The single-crystal elastic constants (C11, C33, C44, C12, and C13) increase monotonically under uniform compression paths, satisfying all Born mechanical stability metrics across the entire tested pressure range. The directional compressibility paths reveal that the crystal c-axis displays exceptional stiffness due to short, covalent molybdenum-silicon bonds interlocking the rows. Electronic density calculations confirm a persistent metallic profile under ultra-high structural strain.
Keywords: Molybdenum disilicide; density functional theory; elastic constants; high pressure; structural stability; polytypes
Manuscript Timeline: Received: June 04, 2024; Revised: July 28, 2024; Accepted: August 18, 2024; Published: September 10, 2024
Citation: Morozov, V. I., & O’Connor, P. J. (2024). Elasticity Profiles and High-Pressure Structural Transformations in Ultra-Incompressible Molybdenum Disilicide Polytypes. International Journal of Physics, 15(9), 65–72.
International Journal of Physics | Vol. 15, No. 8, August 2024 | pp. 57–64
DOI: 10.46882/2024/IJP/000172
Research Article
Title: Optical Soliton Dynamics and Instabilities in Non-Local Plasma Metamaterials with Saturable Non-Linearities
Names of Authors: L. K. Rousseau¹, G. R. Davies²
Authors’ Affiliations:
¹ Laboratoire de Physique des Plasmas, École Polytechnique, Palaiseau, France
² School of Physics and Astronomy, University of St Andrews, St Andrews, UK
Abstract: Controlling ultra-short laser pulse propagation tracks and eliminating high-power beam filamentation are critical operational tasks when developing plasma diagnostic torches, laser-induced fusion trackers, and specialized fast-switching grids. This study models optical soliton dynamics and characterises modulation instability profiles inside non-local plasma metamaterials exhibiting saturable electronic non-linearities. We solved the generalized non-linear Schrödinger equations including higher-order perturbation corrections, specifically third-order dispersion, self-steepening, and delayed Raman response steps. The numerical simulations used a variational approach paired with split-step Fourier schemes to extract exact single-soliton and breather solutions. The results demonstrate that high spatial non-locality parameters effectively suppress catastrophic self-focusing collapse nodes by smoothing localized wavefront phase errors. The modulation instability growth rate was tracked against changing spatial perturbation frequencies, highlighting a maximum gain coefficient of g = 2.92 cm⁻¹ under an input beam intensity of 2.0 kW/cm². Expanding the non-locality parameter scales down the maximum instability gain by 68.0%, preventing pulse fragmentation across waveguides.
Keywords: Nonlinear optics; spatial solitons; nonlinear Schrödinger equation; modulational instability; non-local media; plasma metamaterials
Manuscript Timeline: Received: May 12, 2024; Revised: July 03, 2024; Accepted: July 25, 2024; Published: August 14, 2024
Citation: Rousseau, L. K., & Davies, G. R. (2024). Optical Soliton Dynamics and Instabilities in Non-Local Plasma Metamaterials with Saturable Non-Linearities. International Journal of Physics, 15(8), 57–64.
International Journal of Physics | Vol. 15, No. 7, July 2024 | pp. 49–56
DOI: 10.46882/2024/IJP/000171
Research Article
Title: Quantum Entanglement Kinetics and Decoherence Suppressions in Coupled Five-Level Quantum Dot Lattices
Names of Authors: S. H. Zhang¹, J. W. Park²
Authors’ Affiliations:
¹ Department of Physics, Tsinghua University, Beijing, China
² Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
Abstract: Defending non-classical quantum state correlations from environmental phase relaxation pathways is a vital hurdle for constructing reliable solid-state quantum memory registers and scalable quantum computing networks. This paper investigates the time-dependent kinetic evolution of quantum entanglement and presents active decoherence suppression strategies within coupled five-level semiconductor quantum dot lattices. The architecture models an array coupled to a customized optical microcavity and interacting with a discrete thermal acoustic phonon bath. We solved the density matrix master equations using an algebraic operator framework matching the Lindblad dissipation rules at a cryogenic operating temperature of 4.2 K. The calculations demonstrate that configuring the laser fields under multi-channel quantum interference conditions effectively decouples the electronic states from radiative cavity mirror paths. This isolation sustains stable bipartite entanglement across continuous runtime blocks exceeding 22.0 ns, preserving a concurrence index above 0.86. We simulated a periodic dynamical pulse sequence that dampens low-frequency charge noise channels. This optimization yields a target quantum gate fidelity calculation of 99.4% ± 0.2%, assisting solid-state design.
Keywords: Quantum entanglement; quantum dots; Lindblad master equation; dynamical decoupling; quantum optics; quantum computing
Manuscript Timeline: Received: April 15, 2024; Revised: June 02, 2024; Accepted: June 22, 2024; Published: July 15, 2024
Citation: Zhang, S. H., & Park, J. W. (2024). Quantum Entanglement Kinetics and Decoherence Suppressions in Coupled Five-Level Quantum Dot Lattices. International Journal of Physics, 15(7), 49–56.