Kibble-Zurek mechanism for nonequilibrium phase transitions in driven systems with quenched disorder

量子物理学・ナノサイエンス第94回特別セミナー

概要

The Kibble-Zurek (KZ) mechanism describes the density of defects as a system is quenched through an equilibrium phase transition. The KZ scenario predicts a universal power law scaling and has implications for continuum phase transitions in the early universe, materials science, and condensed matter systems [1,2]. An open question is whether the KZ scenario also holds for nonequilibrium phase transitions. We show that the Kibble-Zurek mechanism applies to nonequilibrium phase transitions found in driven assemblies of superconducting vortices and colloidal particles moving over quenched disorder where a transition occurs from a plastic disordered flowing state to a moving anisotropic crystal. We measure the density of topological defects as a function of quench rate through the nonequilibrium phase transition, and find that on the ordered side of the transition, the topological defect density ρd scales as a power law with tq, the quench time duration, consistent with the Kibble-Zurek mechanism. We show that scaling with the same exponent holds for varied strengths of quenched disorder and that the exponents fall in the directed percolation (DP) universality class [3]. Our results suggest that the Kibble-Zurek mechanism can be applied to the broader class of systems that exhibit absorbing phase transitions. We also examine a system of skyrmions with a strong Magnus force component that are driven over random disorder and exhibit a dynamic transition from a fluid to a two-dimensional crystal. In this case we find a different set of exponents and we argue that the critical behavior is associated with coarsening since the defects can both climb and glide [4]. We discuss how systems with non-equilibrium phase transitions such as glasses, turbulence, time crystals, or systems exhibiting a reversible-irreversible transition could also be interesting places to look for Kibble-Zurek type dynamics.

(*Collaboration with Cynthia Reichhardt and Adolfo del Campo)

　　　　
• [1]　T.W.B. Kibble, "Topology of cosmic domains and strings." J. Phys. A: Math. Gen. 9, 1387 (1976).
• [2]　W.H. Zurek, "Cosmological experiments in superfluid helium." Nature (London) 317, 505 (1985).
• [3]　C.J.O. Reichhardt, A. del Campo, and C. Reichhardt, "Kibble-Zurek mechanism for nonequilibrium phase transitions in driven systems with quenched disorder." Commun. Phys. 5, 173 (2022).
• [4]　S. Maegochi, K. Ienaga, and S. Okuma, "Kibble-Zurek mechanism for dynamical ordering in a driven vortex system." Phys. Rev. Lett. 129, 227001 (2022).
• [5]　C. Reichhardt, I. Regev, K. Dahmen, S. Okuma, and C.J.O. Reichhardt, Phys. Rev. Research 5, 021001 (2023).

• 量子物理学・ナノサイエンス第94回特別セミナー

• 東京工業大学理学院・物理学系 ナノサイエンスを拓く量子物理学拠点 共催