Quantum Zeno Effect (QZE), a phenomenon where frequent measurements can inhibit the evolution of a quantum system, has garnered significant attention since its discovery by Misra and Sudarshan in 1977. This effect could advance quantum technologies, including suppressing Hawking radiation, enhancing noise sensors, and improving quantum communication and computing. In this work, we investigate the QZE in an asymmetric nonlinear coupler consisting of two distinct channel waveguides: a linear waveguide and a waveguide with second-order nonlinearity. Each waveguide supports a single light mode from a coherent laser source. The nonlinear interaction in the nonlinear waveguide produces second harmonic generation (SHG), doubling the frequency of the input mode to enhance quantum effects. In this setup, the linear waveguide serves as a probe, while the nonlinear waveguide with SHG acts as the primary system. The nonlinear coupler, with its simple structure and versatile configuration, offers an ideal platform for studying the QZE. Unlike the short-length approximation method or the analytical perturbative (AP) method, which approximate quantum system dynamics using a truncated Baker-Campbell-Hausdorff (BCH) formula for computational feasibility-thereby restricting their accuracy, especially in systems with strong interactions-the positive-P representation offers a more precise approach. This phase-space method transforms the system's Hamiltonian into a master equation for the density matrix without requiring truncation, enabling significantly more accurate analysis of the quantum dynamics, even over extended evolution distances. Our findings reveal that the QZE is strongly influenced by the nonlinear coupling magnitude, evanescent coupling strength, and frequency mismatch. These results offer a precise theoretical framework to guide practical applications of the QZE and lay the groundwork for exploring the effect in more complex quantum systems.
The present work investigates the variability of the meridional component of thermospheric winds during 189 days of moderate and high solar activity across the period of 2011-2013. In this study, the characteristics of wind velocity based on local time, season, and solar activity were examined to understand neutral dynamics of the thermosphere over Southeast Asia. The winds velocity was determined from 630nm airglow measured with Fabry-Perot interferometers located at low-latitude stations in Chiang Mai, Thailand (MLAT: 9.4 degrees N, MLON: 172.0 degrees E) and Kototabang, Indonesia (MLAT: 9.5 degrees S, MLON: 172.9 degrees E). Our comparison of the meridional (Vn) and zonal (Ve) component of winds during this time showed distinct differences between the two, with stronger Ve (60-110 m/s) primarily flowing eastward, whereas Ve was weaker (5-60 m/s) with reversals in both poleward and equatorward flow throughout the nighttime. Additionally, our further analysis of Vn reported that winds were stronger and more poleward during winter and summer seasons (75-115 m/s) compared to near equinox months (similar to 50-70 m/s), with velocities reaching peak amplitude earlier in the evening sector (1100-1300 UT) rather than at midnight hours (1600-2200 UT). In this study, there was a slight dependency on solar activity observed, resulting in more variability and reduced wind velocities of up to +/- 5-20 m/s. Fully understanding the relationship between meridional winds and solar activity in this region requires future studies that encompass a wider range of solar activity levels, including low, moderate, and high conditions. These observational results provide important constraints for improving empirical models such as the Horizontal Wind Model (HWM), particularly for low-latitude regions. Enhanced model accuracy can support better space weather forecasting and ionospheric prediction across Southeast Asia.
Gel polymer electrolytes (GPEs) have become a critical component in electrochemical devices such as batteries, supercapacitors, etc. due to their high ionic conductivity, mechanical flexibility, and enhanced safety. In this work, fish skin gelatine (FG) incorporated with varying concentrations of ammonium nitrate (NH4NO3 ) was successfully fabricated using the solution casting technique. Fourier transform infrared (FTIR) spectroscopy confirmed the interaction between FG and NH4NO3 salt. The optimum conductivity, (6.22 +/- 0.16 x 10(-3)) S cm(-1), was achieved for the GPE incorporating 15 wt.% NH4NO3 (GFG15), exhibiting the lowest crystallite size of 1.195 nm. The ion transference number (t(ion)) of GFG15 was determined to be 0.98, signifying its role as a predominantly ionic conductor. Linear sweep voltammetry (LSV) demonstrated the GFG15's suitability for application in a carbon-based symmetric electric double layer capacitor (EDLC). The highest specific capacitance (C-sp) of the electrode was recorded as 98.23 F g(-1) and 74.24 F g(-1) from cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) studies, respectively.
The present work reports the performance of FeSe(2)and Co(3)Se(4 )electrode for supercapacitor. The samples were synthesized via a two-step hydrothermal technique. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and N2 adsorption-desorption technique were implemented as the analytical approaches for material characterizations. To measure the electrochemical performance of FeSe(2 )and Co(3)Se(4 )electrode, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) have been introduced. Co(3)Se(4)electrode depicts a better electrochemical performance in terms of specific capacitance (C-sp) value and charge transfer resistance (R-ct), as compared to FeSe(2 )electrode. Co(3)Se(4 )electrode achieves a maximum C(sp )value of 274.65 F g(-1) at 1 A g(-1), investigated in a 6 M KOH electrolyte solution. The performance superiority can be attributed to the larger surface area, higher porosity and lower R-ct.
Understanding heat, water, and vapor transport in unsaturated soils is crucial for various applications, including agriculture, engineering, and environmental sciences. While existing models, such as those derived from de Vries [1] and Philip and de Vries [2], effectively describe these processes, they struggle with accurately predicting water movement in dry soil regions. Discrepancies in the vapor enhancement factor between heat and mass balance equations and experimental observation (e.g., Heitman et al. [19]; Goh [18]) suggest fundamental misalignments, leading to overestimated heat flux and underestimated water flux. This study re-derives the heat balance equation to identify and address these limitations. Key findings indicate that temperature-dependent latent heat of vaporization should be reconsidered, and the unsaturated hydraulic conductivity model by Fayer and Simmons [23] improves dry-region predictions. Additionally, the vapor volume expansion advection model by Goh and Noborio [31] offers an alternative to the vapor enhancement factor. These refinements could enhance the consistency between heat and mass transport models, improving the accuracy of soil moisture and temperature simulations. The equation improvement provides a stronger theoretical foundation for coupled heat-water transport modeling, with implications for soil management, climate modeling, and subsurface engineering.
