title: Relaxation with long-period oscillation in defect turbulence of planar nematic liquid crystals.
abstract: Through experiments, we studied defect turbulence, a type of spatiotemporal chaos in planar systems of nematic liquid crystals, to clarify the chaotic advection of weak turbulence. In planar systems of large aspect ratio, structural relaxation, which is characterized by the dynamic structure factor, exhibits a long-period oscillation that is described well by a combination of a simple exponential relaxation and underdamped oscillation. The simple relaxation arises as a result of the roll modulation while the damped oscillation is manifest in the repetitive gliding of defect pairs in a local area. Each relaxation is derived analytically by the projection operator method that separates turbulent transport into a macroscopic contribution and fluctuations. The analysis proposes that the two relaxations are not correlated. The nonthermal fluctuations of defect turbulence are consequently separated into two independent Markov processes. Our approach sheds light on diversity and universality from a unified viewpoint for weak turbulence.
authors.affiliation: Faculty of Engineering, Kyushu Sangyo University, Fukuoka 813-8503, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Narumi
authors.affiliation: Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Mikami
authors.affiliation: Department of Electrical and Electronic Engineering, Oita University, Oita 870-1192, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nagaya
authors.affiliation: Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Okabe
authors.affiliation: Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hara
authors.affiliation: Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Hidaka