Spontaneous ordering against an external field in non-equilibrium systems
Spontaneous ordering against an external field in non-equilibrium systems
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DOI：
10.1088/1367-2630/12/1/013010
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发表时间：
2010-01-19
影响因子：
3.3
通讯作者：
San Miguel, M.
中科院分区：
文献类型：
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作者：
Gonzalez-Avella, J. C.;Cosenza, M. G.;San Miguel, M.
我们研究非平衡系统在外场作用下的集体行为，其动力学特征是非相互作用态的存在。为了探索结果的普遍性，我们根据状态变量的性质考虑了两种类型的模型：(I)矢量模型，其中相互作用与状态之间的重叠成比例；(Ii)标量模型，其中相互作用取决于状态之间的距离。对于完全连通网络和随机无标度网络中的每个模型，对其相空间进行了数值表征。对于这两种模型，系统显示三个相：两个有序相，一个与场平行，另一个与场垂直，以及一个无序相。通过将粒子放置在一个小世界网络上，我们证明了在完全连通的、随机的和无标度的网络中，由于存在长程相互作用，处于不同于场施加的状态的有序相是可能的。这一阶段不存在于规则晶格中，当小世界网络中包含长程相互作用时才会出现。
We study the collective behavior of non-equilibrium systems subjected to an external field with a dynamics characterized by the existence of non-interacting states. Aiming at exploring the generality of the results, we consider two types of model according to the nature of their state variables: (i) a vector model, where interactions are proportional to the overlap between the states, and (ii) a scalar model, where interactions depend on the distance between states. The phase space is numerically characterized for each model in a fully connected network and in random and scale-free networks. For both models, the system displays three phases: two ordered phases, one parallel to the field and another orthogonal to the field, and one disordered phase. By placing the particles on a small-world network, we show that an ordered phase in a state different from the one imposed by the field is possible because of the long-range interactions that exist in fully connected, random and scale-free networks. This phase does not exist in a regular lattice and emerges when long-range interactions are included in a small-world network.