Specific heat amplitude ratios for generic competing systems

3rd International Conference on Mathematical Modeling in Physical Sciences

物理学;数学

De Sena, Marcone I.^1 ; Leite, Marcelo M.^1

Laboratório de Física Teórica e Computacional, Departamento de Física, Universidade Federal de Pernambuco, PE, Recife

50670-901, Brazil^1

关键词: Amplitude ratios;    Competing interactions;    Competing systems;    Critical behavior;    Diblock copolymer blends;    Orthogonal approximation;    Physical mechanism;    Universality class;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/574/1/012170/pdf
DOI  :  10.1088/1742-6596/574/1/012170

来源: IOP

【 摘 要 】

The specific heat amplitude ratios for generic anisotropic as well as isotropic Lifshitz critical behaviors for the N-vector model are computed at one-loop level using the L- expansion. In the anisotropic case, we show that the universal result obtained reduces very easily to that from the simpler m-axial universality class result. In the isotropic case, if n is the number of neighbors coupled via competing interactions, we demonstrate that the ratio vanishes close to n 4 and, becomes negative for n > 4 when it is calculated exactly, which is rather odd. The evaluation using the orthogonal approximation is shown to yield positive results for arbitrary n. Explicit computations for the case n 2, d 3, N 1 yield an exact amplitude ratio equal to 0.06, with the approximate amplitude ratio being 1.17.We discuss two physical mechanisms to pick out one of the amplitude ratio values. We propose an experiment in homopolymer-diblock copolymer blends in order to determine the amplitude ratio.