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S. Hutzler

Publications and source records attributed to S. Hutzler.

7 recordsLinked to original sources
arXiv2025

Self-assembled clusters of mutually repelling particles in confinement

Mutually repelling particles form spontaneously ordered clusters when forced into confinement. The clusters may adopt similar spatial arrangements even if the underlying particle interactions are contrastingly different. Here we demonstrate with both simulations and experiments that it is possible to induce particles of very different types to self-assemble into the same ordered geometric structure by simply regulating the ratio between the repulsion and confining forces. This is the case for both long- and short-ranged potentials. This property is initially explored in systems with two-dimensional (2D) circular symmetry and subsequently demonstrated to be valid throughout the transition to one-dimensional (1D) structures through continuous elliptical deformations of the confining field. We argue that this feature can be utilized to manipulate the spatial structure of confined particles, thereby paving the way for the design of clusters with specific functionalities.

cond-mat.soft↗
arXiv2024

Self-assembled clusters of magnetically tilted dipoles

Motivated by the idea of using simple macroscopic examples to illustrate the physics of complex systems, we modify a historic experimental setup in which interacting floating magnets spontaneously self-assemble into ordered clusters. By making the cluster components mechanically stable against their natural tendency to flip and coalesce, we can monitor the torque experienced by individual magnets through the macroscopic tilt angles they acquire when exposed to non-collinear external fields. A mathematical model that reproduces the empirical observations is introduced, enabling us to go beyond the experimental cases considered. The model confirms the existence of alternative orderings as the number of objects increases. Furthermore, a simpler and more mathematically transparent version of our model enables us to establish the conditions under which the cluster structure is stable and when it will collapse. We argue that our simple experimental setup combined with the accompanying models may be useful to describe general features seen in systems composed of mutually repulsive particles in the presence of modulating confining fields.

cond-mat.soft↗
arXiv2018

Ideal wet two-dimensional foams and emulsions with finite contact angle

We present simulations that show that an ideal two-dimensional foam with a finite contact angle develops an inhomogeneity for high liquid fraction $ϕ$. In liquid-liquid emulsions this inhomogeneity is known as flocculation. In the case of an ordered foam this requires a perturbation, but in a disordered foam inhomogeneity grows steadily and spontaneously with $ϕ$, as demonstrated in our simulations performed with the Surface Evolver.

cond-mat.soft↗
arXiv2012

Dense packings of spheres in cylinders I. Simulations

We study the optimal packing of hard spheres in an infinitely long cylinder, using simulated annealing, and compare our results with the analogous problem of packing disks on the unrolled surface of a cylinder. The densest structures are described and tabulated in detail up to D/d=2.873 (ratio of cylinder and sphere diameters). This extends previous computations into the range of structures which include internal spheres that are not in contact with the cylinder.

cond-mat.soft↗
arXiv2006

Two dimensional foam rheology with viscous drag

We formulate and apply a continuum model that incorporates elasticity, yield stress, plasticity and viscous drag. It is motivated by the two-dimensional foam rheology experiments of Debregeas et al. [G. Debregeas, H. Tabuteau, and J.-M. di Meglio, Phys. Rev. Lett. 87, 178305 (2001)] and Wang et al [Y. Wang, K. Krishan, and M. Dennin, Phys. Rev. E 73, 031401 (2006)], and is successful in exhibiting their principal features an exponentially decaying velocity profile and strain localisation. Transient effects are also identified.

cond-mat.soft↗
arXiv2006

Sector analysis for a FTSE portfolio of stocks

Using a portfolio of stocks from the London Stock Exchange FTSE100 index (FTSE), we study both the time dependence of their correlations and the normalized tree length of the associated minimal spanning tree (MST). The first four moments of the distribution of correlations and lengths of the tree are examined in detail and differences in behaviour noted. For different economic groups and industries, clustering is evident. However comparing the classification used prior to 2006 with that introduced in January 2006 it is clear that the new classification, apart from one or two notable exceptions, is much more compatible with the clustering obtained by the MST analysis. We finally compare the MST for real data with that obtained for a synthetic {\it random market}. The latter tree would seem more like the structure found by Coronnello {\it et al.} for trees based on high frequency data.

physics.soc-ph↗