We analyze the statistics of resonance widths in a many-body Fermi system with open decay channels. Depending on the strength of continuum coupling, such a system reveals growing deviations from the standard chi-square (Porter-Thomas) width distribution. The deviations emerge from the process of increasing interaction of intrinsic states through common decay channels; in the limit of perfect coupling this process leads to the superradiance phase transition. The width distribution depends also on the intrinsic dynamics (chaotic versus regular). The results presented here are important for understanding the recent experimental data concerning the width distribution for neutron resonances in nuclei.
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http://dx.doi.org/10.1103/PhysRevLett.106.042501 | DOI Listing |
Electromagn Biol Med
January 2025
Department of Mathematics, University of Gour Banga, Malda, India.
In cardiovascular research, electromagnetic fields generated by Riga plates are utilized to study or manipulate blood flow dynamics, which is particularly crucial in developing treatments for conditions such as arterial plaque deposition and understanding blood behavior under varied flow conditions. This research predicts the flow patterns of blood enhanced with gold and maghemite nanoparticles (gold-maghemite/blood) in an electromagnetic microchannel influenced by Riga plates with a temperature gradient that decays exponentially, under sudden changes in pressure gradient. The flow modeling includes key physical influences like radiation heat emission and Darcy drag forces in porous media, with the flow mathematically represented through unsteady partial differential equations solved using the Laplace transform (LT) method.
View Article and Find Full Text PDFPest Manag Sci
January 2025
Silsoe Spray Applications Unit Ltd, Bedford, UK.
Background: To use unmanned aerial vehicles (UAVs) to deliver pesticides, new data are needed to allow regulators to conduct risk assessments. A field trial was conducted to obtain spray drift data relating to ground deposits and airborne spray resulting from a spray application delivered by a small UAV.
Results: A 12 m width area was sprayed with four passes of the UAV and spray deposits were collected within the sprayed area and up to 50 m downwind.
Optical autocorrelators are typically employed to retrieve the temporal information of bound-state lasers; however, they suffer from limitations when multiple sub-pulses coexist with varying intensities and pulse widths. To this end, this study investigates the impact of differences in pulse temporal intensity and width between two unequal pulses in a bound-state laser on the corresponding autocorrelation trace. Maps of autocorrelation trace in terms of the temporal profile of unequal pulse bound state are created to evaluate their internal relationship.
View Article and Find Full Text PDFThe dissolution/diffusion process of solid in a liquid is a kind of widespread physical phenomenon. Parameters involved in this process include the dissolution rate (), dissolution rate constant (), and diffusion coefficient (), whose accurate measurement is particularly important in fields such as biopharmaceuticals, materials science, agriculture, etc. However, the commonly used measurement methods at present cannot obtain these parameters simultaneously.
View Article and Find Full Text PDFIn this paper, we study the propagation and time-evolution behavior of superfluorescence in an overdamped semiconductor ring microcavity. By introducing a re-coupling mechanism between the unidirectionally propagating superfluorescence and the cooperative exciton state with a specified Gaussian spatial distribution, we can compress the width of the photoluminescence (PL) pulse in both temporal and spatial scales. Using realistic parameters from perovskite superlattice materials, we observe that the maximum intensity increases twofold compared to the ordinary radiation behavior observed in planar microcavity systems.
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