Soft-Mode Turbulence in Electroconvection of Nematics

Hidaka, Yoshiki; Tamura, Koyo; Kai, Shoichi

doi:10.1143/ptps.161.1

Cited by 24 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That is, the memory effects cannot be negligible. According to the fluctuationdissipation relation, our result can also be interpreted as showing the emergence of non-thermal noise in SMT, as supported by the Lagrangian picture [21,41]. It is consequently noteworthy that the non-thermal fluctuation caused by the patch structure leads to non-exponential relaxation.…”

supporting

confidence: 75%

Glassy dynamics in relaxation of soft-mode turbulence

Nugroho¹,

Narumi²,

Hidaka³

et al. 2012

Phys. Rev. E

Self Cite

View full text Add to dashboard Cite

The autocorrelation function of pattern fluctuation is used to study soft-mode turbulence (SMT), a spatiotemporal chaos observed in homeotropic nematics. We show that relaxation near the electroconvection threshold deviates from the exponential. To describe this relaxation, we propose a compressed exponential appearing in dynamics of glass-forming liquids. Our findings suggest that coherent motion contributes to SMT dynamics. We also confirmed that characteristic time is inversely proportional to electroconvection's control parameter.

show abstract

supporting

confidence: 75%

Glassy dynamics in relaxation of soft-mode turbulence

Nugroho¹,

Narumi²,

Hidaka³

et al. 2012

Phys. Rev. E

Self Cite

View full text Add to dashboard Cite

show abstract

“…The interaction between the convective and Goldstone modes are different between oblique and normal rolls [45,46]; the convective wave vector in SMT tend to become parallel to the C-director in the normal roll and oblique in the oblique roll. The patch structure is observed only in the oblique rolls [13,14].…”

Section: Soft-mode Turbulencementioning

confidence: 95%

Compressed exponential relaxation as superposition of dual structure in pattern dynamics of nematic liquid crystals

Narumi

Nugroho

Yoshitani

et al. 2013

AIP Conference Proceedings

View full text Add to dashboard Cite

Soft-mode turbulence (SMT) is the spatiotemporal chaos observed in homeotropically aligned nematic liquid crystals, where non-thermal fluctuations are induced by nonlinear coupling between the NambuGoldstone and convective modes. The net and modal relaxations of the disorder pattern dynamics in SMT have been studied to construct the statistical physics of nonlinear nonequilibrium systems. The net relaxation dynamics is well-described by a compressed exponential function and the modal one satisfies a dual structure, dynamic crossover accompanied by a breaking of time-reversal invariance. Because the net relaxation is described by a weighted mean of the modal ones with respect to the wave number, the compressed-exponential behavior emerges as a superposition of the dual structure. Here, we present experimental results of the power spectra to discuss the compressed-exponential behavior and the dual structure from a viewpoint of the harmonic analysis. We also derive a relationship of the power spectra from the evolution equation of the modal autocorrelation function. The formula will be helpful to study non-thermal fluctuations in experiments such as the scattering methods.

show abstract

“…The region can be regarded as the origin of the long correlation length of spatiotemporal chaos. SMT contains such areas called a patch structure, in which the direction of the convective rolls is uniform [10]. The structure contributes strongly to the SMT dynamics enabling the dual structure to emerge that violates macroscopic time-reversal invariance [22].…”

Section: A Relaxation With Long-period Oscillationmentioning

confidence: 99%

“…With homeotropic alignment, the director is perpendicular to the electrodes and the continuous rotational symmetry on the electrode substrates exists. As the applied voltage increases, the continuous rotational symmetry is broken spontaneously by the Fréedericksz instability [9], and thus the director behaves as a Nambu-Goldstone mode induced by symmetry breaking [10]. Above the threshold of electroconvection, the Nambu-Goldstone mode leads to a type of spatiotemporal chaos, called soft-mode turbulence (SMT) [11,12].…”

Section: Introductionmentioning

confidence: 99%

Relaxation with long-period oscillation in defect turbulence of planar nematic liquid crystals

et al. 2016

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Soft-Mode Turbulence in Electroconvection of Nematics

Cited by 24 publications

References 0 publications

Glassy dynamics in relaxation of soft-mode turbulence

Glassy dynamics in relaxation of soft-mode turbulence

Compressed exponential relaxation as superposition of dual structure in pattern dynamics of nematic liquid crystals

Relaxation with long-period oscillation in defect turbulence of planar nematic liquid crystals

Contact Info

Product

Resources

About