Thomsen H, Bonitz M
Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Apr;91(4):043104. doi: 10.1103/PhysRevE.91.043104. Epub 2015 Apr 21.
Finite systems in confining potentials are known to undergo structural transitions similar to phase transitions. However, these systems are inhomogeneous, and their "melting" point may depend on the position in the trap and vary with the particle number. Focusing on three-dimensional Coulomb systems in a harmonic trap a rich physics is revealed: in addition to radial melting we demonstrate the existence of intrashell disordering and intershell angular melting. Our analysis takes advantage of a novel melting criterion that is based on the spatial two- and three-particle distribution functions and the associated reduced entropy which can be directly measured in complex plasma experiments.
已知处于限制势中的有限系统会经历类似于相变的结构转变。然而，这些系统是不均匀的，它们的“熔点”可能取决于陷阱中的位置，并随粒子数而变化。聚焦于谐波陷阱中的三维库仑系统，揭示了丰富的物理现象：除了径向熔化，我们还证明了壳内无序和壳间角向熔化的存在。我们的分析利用了一种基于空间两粒子和三粒子分布函数以及相关约化熵的新型熔化判据，这些在复杂等离子体实验中可以直接测量。
