Salmon Octavio D Rodriguez, Nobre Fernando D
Departamento de Física, Universidade Federal do Amazonas, 3000, Japiim 69077-000, Manaus-AM, Brazil.
Centro Brasileiro de Pesquisas Físicas and National Institute of Science and Technology for Complex Systems, Rua Xavier Sigaud 150 22290-180, Rio de Janeiro-RJ, Brazil.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jun;89(6):062104. doi: 10.1103/PhysRevE.89.062104. Epub 2014 Jun 4.
A system defined by two coupled Ising models, with a bimodal random field acting in one of them, is investigated. The interactions among variables of each Ising system are infinite ranged, a limit where mean field becomes exact. This model is studied at zero temperature, as well as for finite temperatures, representing physical situations which are appropriate for describing real systems, such as plastic crystals. A very rich critical behavior is found, depending directly on the particular choices of the temperature, couplings, and random-field strengths. Phase diagrams exhibiting ordered, partially ordered, and disordered phases are analyzed, showing the sequence of transitions through all these phases, similarly to what occurs in plastic crystals. Due to the wide variety of critical phenomena presented by the model, its usefulness for describing critical behavior in other substances is also expected.
研究了一个由两个耦合伊辛模型定义的系统，其中一个模型中有一个双峰随机场作用。每个伊辛系统变量之间的相互作用是长程的，在这个极限下平均场理论变得精确。该模型在零温度以及有限温度下进行研究，代表了适合描述真实系统（如塑性晶体）的物理情形。发现了非常丰富的临界行为，它直接取决于温度、耦合以及随机场强度的特定选择。分析了展示有序、部分有序和无序相的相图，显示了通过所有这些相的转变序列，这与塑性晶体中的情况类似。由于该模型呈现出各种各样的临界现象，预计它对描述其他物质的临界行为也有用。
