Progress of quantum molecular dynamics model and its applications in heavy ion collisions

Abstract

In this review article, we first briefly introduce the transport theory and quantum molecular dynamics model applied in the study of the heavy ion collisions from low to intermediate energies.The developments of improved quantum molecular dynamics model (ImQMD) and ultra-relativistic quantum molecular dynamics model (UrQMD), are reviewed. The reaction mechanism and phenomena related to the fusion, multinucleon transfer, fragmentation, collective flow and particle production are reviewed and discussed within the framework of the two models. The constraints on the isospin asymmetric nuclear equation of state and in-medium nucleon-nucleon cross sections by comparing the heavy ion collision data with transport models calculations in last decades are also discussed, and the uncertainties of these constraints are analyzed as well. Finally, we discuss the future direction of the development of the transport models for improving the understanding of the reaction mechanism, the descriptions of various observables, the constraint on the nuclear equation of state, as well as for the constraint on in-medium nucleon-nucleon cross sections.

Influence of the treatment of initialization and mean-field potential on the neutron to proton yield ratios

“…The treatment of nucleon-nucleon collision, Pauli blocking and others are as same as in previous version of ImQMD. More details about them can be found in the review paper [46]. The improvements we made in this work are the initialization and nucleonic mean-field potential.…”

“…, and δ = (ρ n −ρ p )/(ρ n +ρ p ). Here, r i and p i are centroids of distribution, and also the variational parameters of Gaussian single-particle wave functions [46].…”

“…by omitting the higher order term [46,[49][50][51] or adjusting the value of σ r in three-body term [41,44]. The threebody force acting on particle i is calculated according to the followings expression,…”

Molecular dynamics for collisions of heavy ions

“…Foundations for the molecular dynamics were laid out in the community of German physicists [4,5], but benefits of the approach were quickly recognized elsewhere. Prof. Zhuxia Li pioneered the approach in China and she and the next generation of physicists she educated, including Ying-Xun Zhang, the main author of the review [6], made molecular dynamics models an everyday tool for describing heavy-ion collisions at low and intermediate en- * Received February 15, 2021. This article can also be found at http://journal.hep.com.cn/fop/EN/10.1007/ s11467-021-1058-9.…”

“…In Ref. [6], Ying-Xun Zhang, Ning Wang, and their collaborators systematically reviewed the molecular dynamics and its application to heavy ion collisions at low and intermediate energies.…”