ﻻ يوجد ملخص باللغة العربية
Comparison of hydrodynamic calculations with experimental data inevitably requires a model for converting the fluid to particles. In this work, nonlinear $2to 2$ kinetic theory is used to assess the overall accuracy of various shear viscous fluid-to-particle conversion models, such as the quadratic Grad corrections, the Strickland-Romatschke (SR) ansatz, self-consistent shear corrections from linearized kinetic theory, and the correction from the relaxation time approach. We test how well the conversion models can reconstruct, using solely the hydrodynamic fields computed from the transport, the phase space density for a massless one-component gas undergoing a 0+1D longitudinal boost-invariant expansion with approximately constant specific shear viscosity in the range $sim 0.03 le eta/s le sim 0.2$. In general we find that at early times the SR form is the most accurate, whereas at late times or for small $eta/ssim 0.05$ the self-consistent corrections from kinetic theory perform the best. In addition, we show that the reconstruction accuracy of additive shear viscous $f = f_{rm eq} + delta f$ models dramatically improves if one ensures, through exponentiation, that $f$ is always positive. We also illustrate how even more accurate viscous $delta f$ models can be constructed if one includes information about the past evolution of the system via the first time derivative of hydrodynamic fields. Such time derivatives are readily available in hydrodynamic simulations, though usually not included in the output.
We show that the total kinetic energy (TKE) of nuclei after the spontaneous fission of $^{258}$Fm can be well reproduced using simple assumptions on the quantum collective phase-space explored by the nucleus after passing the fission barrier. Assumin
We extend our hybrid model HydHSD by taking into account shear viscosity within the Israel-Stewart hydrodynamics. The influence of different forms of $pi^{mu u}$ constraints on observables is analyzed. We show that the form of the corresponding condi
The specific shear viscosity $bareta$ of a classically rotating system of nucleons that interact via a monopole pairing interaction is calculated including the effects of thermal fluctuations and coupling to pair vibrations within the selfconsistent
The shear viscosity of hot nuclear matter is investigated by using the mean free path method within the framework of IQMD model. Finite size nuclear sources at different density and temperature are initialized based on the Fermi-Dirac distribution. T
In this work we present the first steps towards benchmarking isospin symmetry breaking in ab initio nuclear theory for calculations of superallowed Fermi $beta$-decay. Using the valence-space in-medium similarity renormalization group, we calculate b