2021/11/12 by I. Kovács, Kovács, István A. · 2 citations
Physics and Astronomy · #Theoretical and Computational Physics #Quantum many-body systems #Opinion Dynamics and Social Influence
paper · pdf · doi:10.48550/arxiv.2111.06828
Quantum multicritical points (QMCPs) emerge at the junction of two or more\nquantum phase transitions due to the interplay of disparate fluctuations,\nleading to novel universality classes. While quantum critical points have been\nwell characterized, our understanding of QMCPs is much more limited, even\nthough they might be less elusive to study experimentally than quantum critical\npoints. Here, we characterize the QMCP of an interacting heterogeneous quantum\nsystem in two and three dimensions, the ferromagnetic random transverse-field\nIsing model (RTIM). The QMCP of the RTIM emerges due to both geometric and\nquantum fluctuations, studied here numerically by the strong disorder\nrenormalization group method. The QMCP of the RTIM is found to exhibit\nultraslow, activated dynamic scaling, governed by an infinite disorder fixed\npoint. This ensures that the obtained multicritical exponents tend to the exact\nvalues at large scales, while also being universal -- i.e. independent of the\nform of disorder -- , providing a solid theoretical basis for future\nexperiments.\n