International Journal of Physics | Vol. 5, No. 12, December 2014 | pp. 89–96
DOI: 10.46882/2014/IJP/000056
Research Article
Title: Quantum Entanglement Dynamics and Decoherence Controls in Driven Three-Level Atomic Systems
Names of Authors: S. H. Zhang¹, R. M. Colombo²
Authors’ Affiliations: ¹Department of Physics, Tsinghua University, Beijing, China; ²Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome, Italy
Abstract: Preserving quantum correlations against environmental noise is a major bottleneck in developing scalable quantum information processing architectures. This paper investigates the time-dependent evolution of quantum entanglement and evaluates active decoherence control strategies within driven three-level atomic systems. The system models a lambda-type atom coupled to a lossy optical microcavity interacting with a localized thermal phonon bath. We utilized the density matrix master equation framework within the Lindblad dissipation model at an operating temperature of 4.2 K. Our numerical calculations show that configuring the driving laser fields under electromagnetically induced transparency conditions effectively decouples the atomic state from the cavity decay channel. This decoupling preserves bipartite entanglement for durations exceeding 15.0 ns, maintaining a concurrence value above 0.82. We simulated an active dynamical decoupling pulse sequence that suppresses phase relaxation caused by low-frequency phonon noise. The optimized sequence yielded a quantum gate operation fidelity of 99.1% ± 0.2%. These findings provide an effective theoretical framework for designing noise-resistant quantum memory registers and stabilizing non-classical states within complex quantum networks.
Keywords: Quantum entanglement; decoherence; three-level atom; Lindblad master equation; dynamical decoupling; electromagnetically induced transparency
Manuscript Timeline: Received: August 19, 2014; Revised: October 10, 2014; Accepted: November 02, 2014; Published: December 15, 2014
Citation: Zhang, S. H., & Colombo, R. M. (2014). Quantum Entanglement Dynamics and Decoherence Controls in Driven Three-Level Atomic Systems. International Journal of Physics, 5(12), 89–96.
International Journal of Physics | Vol. 5, No. 11, November 2014 | pp. 81–88
DOI: 10.46882/2014/IJP/000055
Research Article
Title: Superconducting Phase Transitions and Magnetic Flux Pinning Mechanisms in Niobium-Titanium Thin Films
Names of Authors: O. K. Semenov¹, A. L. Vance²
Authors’ Affiliations: ¹Institute for Solid State Physics, Russian Academy of Sciences, Moscow, Russia; ²Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
Abstract: Enhancing the current-carrying capability of superconductors under strong magnetic fields is a critical requirement for next-generation particle accelerators and magnetic resonance imaging systems. This study evaluates the superconducting phase transitions and maps magnetic flux pinning mechanisms in niobium-titanium (Nb-Ti) thin films. The thin films were prepared via magnetron sputtering on sapphire substrates with film thicknesses ranging from 50.0 nm to 300.0 nm. We conducted low-temperature electrical transport and magnetometry measurements across a temperature range of 2.0 K to 15.0 K under magnetic fields up to 8.0 T. The pristine 300.0 nm film displayed a sharp superconducting transition with a critical temperature (Tc) of 9.2 K at zero field. Magnetization loops revealed a high critical current density (Jc) exceeding 3.5 x 10^6 A/cm² at 4.2 K. Analysis of the pinning force density indicates that the dominant pinning mechanism shifts from core-surface pinning to point-defect pinning as the temperature approaches Tc. The upper critical field, Hc2(0), was estimated to be 11.4 T by applying the Werthamer-Helfand-Hohenberg theoretical model. These findings demonstrate that nanoscale grain boundary control significantly improves vortex lattice stability, offering structural strategies for high-field superconducting applications.
Keywords: Superconductivity; thin films; flux pinning; critical current density; upper critical field; magnetron sputtering
Manuscript Timeline: Received: July 14, 2014; Revised: September 02, 2014; Accepted: September 24, 2014; Published: November 12, 2014
Citation: Semenov, O. K., & Vance, A. L. (2014). Superconducting Phase Transitions and Magnetic Flux Pinning Mechanisms in Niobium-Titanium Thin Films. International Journal of Physics, 5(11), 81–88.
International Journal of Physics | Vol. 5, No. 10, October 2014 | pp. 73–80
DOI: 10.46882/2014/IJP/000054
Research Article
Title: Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Germanium Interfacial Defects
Names of Authors: M. G. Richter¹, C. H. Jenkins²
Authors’ Affiliations: ¹Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany; ²Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
Abstract: Minimizing thermal transport across semiconductor boundary layers is crucial for designing high-efficiency solid-state thermoelectric cooling devices. This paper uses molecular dynamics simulations to quantify thermal dispersion metrics and track phonon wavepacket scattering at defective silicon-germanium (Si-Ge) interfaces. We constructed atomistic models using the optimized Stillinger-Weber potential, incorporating varying concentrations of interfacial point defects and atomic roughness steps. Longitudinal and transverse acoustic phonon wavepackets were generated with narrow frequency spreads centered between 2.0 THz and 8.0 THz. The computational data demonstrate that high-frequency acoustic phonons (f greater than 5.0 THz) undergo strong diffuse scattering at the rough interface, dropping the transmission coefficient from 0.82 down to 0.24. This diffuse scattering is driven by localized strain fields and localized interface vibrational modes. The overall interfacial thermal conductance was calculated to decrease by 45.0% when the interfacial roughness parameter scaled from 0.1 nm to 0.6 nm at 300.0 K. These molecular dynamics calculations clarify the atomic-scale mechanisms restricting heat carrier propagation, helping engineers design targeted thermal barriers for nanoscale electronics.
Keywords: Thermal dispersion; phonon wavepacket; molecular dynamics; interface roughness; thermoelectric cooling; silicon-germanium
Manuscript Timeline: Received: June 11, 2014; Revised: August 04, 2014; Accepted: August 28, 2014; Published: October 17, 2014
Citation: Richter, M. G., & Jenkins, C. H. (2014). Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Germanium Interfacial Defects. International Journal of Physics, 5(10), 73–80.
International Journal of Physics | Vol. 5, No. 9, September 2014 | pp. 65–72
DOI: 10.46882/2014/IJP/000053
Research Article
Title: Relativistic Hydrodynamic Modeling of Particle Production Cascades in Asymmetric Proton-Lead Collisions
Names of Authors: H. L. Mueller¹, A. O. Awosika²
Authors’ Affiliations: ¹Institut für Kernphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany; ²Department of Physics, University of Ibadan, Ibadan 200005, Nigeria
Abstract: Asymmetric proton-lead (p-Pb) collisions provide a crucial baseline for isolating cold nuclear matter effects from the collective signature of the quark-gluon plasma. This study presents a relativistic hydrodynamic modeling framework to simulate particle production cascades in p-Pb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. We utilized a 3+1 dimensional viscous hydrodynamic code coupled with a statistical hadronization module to compute transverse momentum spectra and azimuthal anisotropy coefficients. The initial energy density profiles were generated using a Glauber-Gribov color-fluctuation model to capture sub-nucleon scale configurations. The numerical simulations show that expanding systems build a substantial radial flow profile, which shifts the mean transverse momentum of protons up to 1.45 GeV/c in high-multiplicity events. The calculated elliptic flow coefficient (v²) displays a strong mass-ordering effect, which matches experimental measurements gathered by the ALICE detector within a tight ±6.0% margin. This close agreement suggests that small-scale systems generated in p-Pb collisions can achieve brief hydrodynamic collective expansion. These findings help clarify the boundaries of fluid-like behavior in high-energy subatomic particle interactions.
Keywords: Relativistic hydrodynamics; particle production; proton-lead collisions; elliptic flow; color-fluctuation model; statistical hadronization
Manuscript Timeline: Received: May 20, 2014; Revised: July 11, 2014; Accepted: August 02, 2014; Published: September 15, 2014
Citation: Mueller, H. L., & Awosika, A. O. (2014). Relativistic Hydrodynamic Modeling of Particle Production Cascades in Asymmetric Proton-Lead Collisions. International Journal of Physics, 5(9), 65–72.
International Journal of Physics | Vol. 5, No. 8, August 2014 | pp. 57–64
DOI: 10.46882/2014/IJP/000052
Research Article
Title:
Names of Authors: A. M. El-Chemali¹, K. K. Tanaka²
Authors’ Affiliations: ¹Department of Physics, Faculty of Science, Lebanese University, Beirut, Lebanon; ²Department of Quantum Engineering, Nagoya University, Nagoya 464-8603, Japan
Abstract: Noble gas mixtures are widely used in radiation detectors, plasma display panels, and gas discharge lasers. This study developed a self-consistent kinetic simulation model to analyze electron transport properties and compute ionization yields in low-pressure neon-xenon (Ne-Xe) gas mixtures. We solved the electron Boltzmann equation using a multi-term spherical harmonic expansion scheme across a reduced electric field range (E/N) from 2.0 Td to 400.0 Td. The model incorporates comprehensive cross-section sets, including elastic scattering, electronic excitation, and direct impact ionization, while accounting for Penning ionization processes. Our modeling results show that adding small fractions of xenon (from 1.0% to 5.0% by volume) drastically modifies the electron energy distribution function. At a low field strength of E/N = 20.0 Td, the first ionization coefficient increases by over two orders of magnitude in the 99% Ne - 1% Xe mixture compared to pure neon. This enhancement is driven by Penning collisions between metastable neon atoms and ground-state xenon atoms. The calculated electron drift velocities and characteristic energies agree with experimental swarm measurements within a ±4.5% variance. These kinetic parameters help optimize the operating voltages and tracking resolution of gaseous radiation detectors.
Keywords: Neon-xenon mixtures; Boltzmann equation; electron transport; Penning ionization; cross-section; gas detectors
Manuscript Timeline: Received: April 18, 2014; Revised: June 03, 2014; Accepted: June 25, 2014; Published: August 18, 2014
Citation: El-Chemali, A. M., & Tanaka, K. K. (2014). Kinetic Simulation of Electron Transport and lonization Yields in Low-Pressure Neon-Xenon Gas Mixtures. International Journal of Physics, 5(8), 57–64.
International Journal of Physics | Vol. 5, No. 7, July 2014 | pp. 49–56
DOI: 10.46882/2014/IJP/000051
Research Article
Title: High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Osmium Diboride
Names of Authors: V. I. Morozov¹, J. K. Thornton²
Authors’ Affiliations: ¹Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow 142190, Russia; ²Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
Abstract: Designing ultra-incompressible materials capable of withstanding extreme mechanical stress is vital for industrial tooling and high-pressure research components. This paper examines the high-pressure elastic moduli and structural stability of orthorhombic osmium diboride (OsB²) up to hydrostatic pressures of 120.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework. At zero pressure, the calculated bulk modulus is B0 = 365.0 GPa, with an elastic derivative value of B0' = 4.12. These results match experimental diamond anvil cell measurements within a 1.5% margin. The single-crystal elastic constants (C11, C22, C33, C44, C55, and C66) increase monotonically under compression, satisfying all Born mechanical stability conditions across the tested pressure range. The directional compressibility curves reveal that the crystal c-axis is significantly stiffer than the a-axis and b-axis, which is due to short, covalent osmium-boron bonds aligned along the [001] plane. The electronic structure calculations show a high density of states at the Fermi level, indicating that OsB² retains its metallic character under high pressure. These precise elastic profiles confirm the potential of transition metal borides as viable alternatives to diamond-based superhard materials.
Keywords: Osmium diboride; density functional theory; elastic constants; high pressure; mechanical stability; directional compressibility
Manuscript Timeline: Received: March 15, 2014; Revised: May 02, 2014; Accepted: May 28, 2014; Published: July 11, 2014
Citation: Morozov, V. I., & Thornton, J. K. (2014). High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Osmium Diboride. International Journal of Physics, 5(7), 49–56.