We demonstrate that the phase transition from columnar-hexagonal liquid crystal to hexagonal-crystalline solid falls into an unusual universality class, which in three-dimensional allows for both discontinuous transitions as well as continuous transitions, characterized by a single set of exponents. We show by a renormalization group calculation (to first order in $ε= 4-d$) that the critical exponents of the continuous transition are precisely those of the XY model, which gives rise to a continuous evolution of elastic moduli. Although the fixed points of the present model are found to be identical to the XY model, the elastic compliance to deformations in the plane of hexagonal order, $μ$, is nonetheless shown to critically influence the crystallization transition, with the continuous transition being driven to first order by fluctuations as the in plane response grows weaker, $μ\to 0$.
Cell size heterogeneity controls crystallization of the developing fruit fly wing
Max-Planck Institute for Physics of Complex Systems（马克斯·普朗克复杂系统物理学研究所）；DataLoch；University of Edinburgh（爱丁堡大学）；Université Paris Cité（巴黎西岱大学）；Institut Pasteur（巴斯德研究所）；Inserm（法国国家健康与医学研究院）；Cluster of Excellence Physics of Life, TUD（德累斯顿工业大学生命物理卓越集群）；Mechanobiology Institute, National University of Singapore（新加坡国立大学生物力学研究所）
Charge and Salt Driven Reentrant Order-Disorder and Gas-Solid Transitions in Charged Colloids
蒙特卡罗模拟已被执行的含水带电胶体悬浮液作为一个功能的电荷密度的颗粒和盐浓度。我们在我们的模拟中在一定范围内改变电荷密度，其中Yamanaka等人已经报道了二氧化硅和聚合物胶乳颗粒悬浮液中的重入固-液转变[Phys. Rev. Lett. 80 5806（1998）]。我们表明，在低离子强度的均匀液体状有序悬浮液进行结晶时，增加电荷密度。电荷密度的进一步增加再次导致无序状态，这与实验观察一致。除了这种可重入的有序无序过渡，我们观察到一个不均匀的均匀过渡在我们的模拟时，盐被添加到无序的不均匀状态。这种从非均匀到均匀的无序转变类似于原子系统的固-气转变，但在带电胶体中尚未观察到。根据目前的模拟结果，带电胶体悬浮液的实验观察报告进行了讨论。
