Speaker
Description
Our research aims to examine critical behavior of a magnetic system under the influence of two competing factors: long-range interaction and weak structural disorder (e.g., weak quenched dilution). We analyze ferromagnetic ordering in a structurally-disordered magnet within an $n$-vector model in $d$-dimensional space, where the long-range interaction decays with distance $x$ as $J(x) \sim x^{-d -\sigma}$, where with $\sigma$ as is the control parameter. Field-theoretical renormalization group methods (RG) are used to identify the system’s universality classes, and the universal characteristics of critical behavior depending on the global parameters $d, n, \sigma$. We demonstrate that there exists a parameter region $(d, n, \sigma)$, where the interplay of long-range interaction and structural disorder leads to emergence of a new structural-disorder-induced long-range universality class. Using fixed spatial dimension approach we extract values of correlation length critical exponent $\nu$ characterizing this class from perturbative RG functions at $d = 3$ applying asymptotic series resummation methods.
This work was supported by the National Research Foundation of Ukraine, Project 246/0099 "Criticality of complex systems: fundamental aspects and applications" .
