abstract

We utilized the AMPT model to simulate the shear viscous transport dynamics of parton matter with varying specific shear viscosity and phase-transition temperatures and investigate the effect on the HBT radii of charged pions at the \(\sqrt {s_{NN}}=200\) GeV Au\(+\)Au collisions. The emission-source size is sensitive to the shear viscosity of parton matter, thus, increasing the shear viscosity to entropy density ratio will reduce the HBT radii. The phase-transition temperature can regulate the evolution duration of the parton and hadron phases. Raising the phase-transition temperature shortens the evolution time of the partonic phase and extends the evolution time of the hadronic phase, resulting in an increase in the total system evolution time. A prolonged hadronic-phase evolution weakens the dependence of the transverse HBT radii on transverse mass and increases the evolution time scale.

abstract

The time evolution of the distribution function for a particle–hole excitation in a Fermi system was calculated using the direct numerical solution of a nonlinear diffusion equation in momentum space. A phenomenological expression for calculating the relaxation time of such an excitation to its equilibrium value has been proposed. It is shown that the relaxation time is dependent on both the excitation energy and the mass number.

abstract

Advanced facilities like GSI-FAIR in Germany or RIKEN in Japan are dedicated to the research of nuclei far from the stability line. In this paper, we study the fragmentation of relativistic projectiles as a production method for these nuclei, with particular emphasis on the role of secondary reactions.

abstract

This note provides a comprehensive examination of the various approaches to formulating relativistic hydrodynamics, with a particular emphasis on the canonical approach. Relativistic hydrodynamics plays a crucial role in understanding the behavior of fluids in high-energy astrophysical phenomena and heavy-ion collisions. The canonical approach is explored in detail, highlighting its foundational principles, mathematical formulations, and practical implications in modeling relativistic fluid dynamics. Following this, we delve into the linear response theory, elucidating its relevance in the context of hydrodynamics. We analyze the response of relativistic fluids to external perturbations, discussing the theoretical framework and key results. This dual focus aims to bridge the gap between theoretical foundations and practical applications, offering a robust perspective on the dynamic interplay between relativistic hydrodynamics and linear response theory.