Hobrecht Hendrik, Hucht Alfred
Fakultät für Physik and CENIDE, Universität Duisburg-Essen, D-47048 Duisburg, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Oct;92(4):042315. doi: 10.1103/PhysRevE.92.042315. Epub 2015 Oct 27.
We study the fluctuation-induced Casimir interactions in colloidal suspensions, especially between colloids immersed in a binary liquid close to its critical demixing point. To simulate these systems, we present a highly efficient cluster Monte Carlo algorithm based on geometric symmetries of the Hamiltonian. Utilizing the principle of universality, the medium is represented by an Ising system while the colloids are areas of spins with fixed orientation. Our results for the Casimir interaction potential between two particles at the critical point in two dimensions perfectly agree with the exact predictions. However, we find that in finite systems the behavior strongly depends on whether the Z(2) symmetry of the system is broken by the particles. We present Monte Carlo results for the three-body Casimir interaction potential and take a close look onto the case of one particle in the vicinity of two adjacent particles, which can be calculated from the two-particle interaction by a conformal mapping. These results emphasize the failure of the common decomposition approach for many-particle critical Casimir interactions.
我们研究了胶体悬浮液中波动诱导的卡西米尔相互作用，特别是浸没在接近其临界混合点的二元液体中的胶体之间的相互作用。为了模拟这些系统，我们基于哈密顿量的几何对称性提出了一种高效的团簇蒙特卡罗算法。利用普适性原理，介质由伊辛系统表示，而胶体是具有固定取向的自旋区域。我们关于二维临界点处两个粒子之间卡西米尔相互作用势的结果与精确预测完全一致。然而，我们发现，在有限系统中，行为强烈取决于系统的(Z(2))对称性是否被粒子打破。我们给出了三体卡西米尔相互作用势的蒙特卡罗结果，并仔细研究了一个粒子在两个相邻粒子附近的情况，这可以通过共形映射从两体相互作用计算得出。这些结果强调了多粒子临界卡西米尔相互作用的常见分解方法的失效。
