arXiv subjects

Mikheil Kharbedia

Publications and source records attributed to Mikheil Kharbedia.

4 recordsLinked to original sources

arXiv2026

Wilson-Fisher renormalization of discrete gravity-capillary wave turbulence in viscous fluids

We report an experimental realization of Wilson-Fisher renormalization in driven surface-wave turbulence across Newtonian fluids spanning nearly six decades in Raynolds number. Discrete capillary and gravity turbulence define two universality classes selected by interaction topology: triadic resonances for capillary waves and effectively tetradic scattering for gravity waves. Navier-Stokes viscosity is the relevant perturbation that renormalizes spectral transfer and terminates the cascade. The resulting framework predicts the Kolmogorov cutoff from the balance of nonlinear transfer and viscous damping, and Reynolds scaling of the integrated inertial spectral weight. Laser Doppler Vibrometry quantitatively confirms these renormalized scaling laws, establishing discrete gravity-capillary turbulence as a tunable laboratory for nonequilibrium crossoever criticality.

physics.flu-dyn↗

arXiv2025

Active Extensile Hydrogels Actuated by Living Polymers of the Bacterial Cytokinetic Protein FtsZ

Active materials capable of autonomously modulating their mechanical properties are foundational to the development of next-generation soft technologies. Here, we introduce a novel class of extensible biohybrid hydrogels powered by living polymers of the bacterial cytokinetic protein FtsZ. When embedded within a polyacrylamide (PA) matrix, GTP-fueled FtsZ filaments self-organize into treadmilling structures that generate internal extensible stresses, driving reversible softening, swelling, and fluidization of the composite FtsZ-PA hydrogel network. Unlike conventional contractile biopolymer systems, these hybrid gels exhibit stress-induced softening, yield under minimal deformation, and suppress thermal flow barriers-hallmarks of dissipative, extensile metamaterials. Microscopic particle tracking reveals active non-Gaussian fluctuations, while bulk rheology confirms programmable, concentration-dependent reductions in both stiffness and viscosity. Theoretical modeling shows that internal filament activity gives rise to a negative mechanical permittivity, establishing a new paradigm in materials science in which embedded FtsZ living polymers dynamically program active matter mechanics from within. These findings open new avenues for the design of modular, reconfigurable systems in adaptive biomaterials, soft robotics, and synthetic active matter.

cond-mat.soft↗

arXiv2024

Collective lattice excitations in the dynamic route for melting hydrodynamic 2D-crystals

Surface stiffnesses engender steady patterns of Faraday waves (FWs), so called hydrodynamic crystals as correspond to ordered wave lattices made of discrete subharmonics under monochromatic driving. Mastering rules are both inertia-imposed parametric resonance for frequency-halving together with rigidity-driven nonlinearity for wavefield self-focusing. They harness the discretization needed for coherent FW-packets to localize in space and time. Collective lattice excitations are observed as dispersionless propagating dislocations that lead periodic modulations arising from explicit symmetry breaking. In a field theory perspective, a halving genesis for the collective distorting modes is revealed as the natural pathway for hydrodynamic crystal melting.

nlin.PS↗

arXiv2020

Moulding hydrodynamic 2D-crystals upon parametric Faraday waves in shear-functionalized water surfaces

Faraday waves (FWs), or surface waves oscillating at half of the natural frequency when a liquid is vertically vibrated, are archetypes of ordering transitions on liquid surfaces. The existence of unbounded FW-patterns sustained upon bulk frictional stresses has been evidenced in highly viscous fluids. However, the role of surface rigidity has not been investigated so far. Here, we demonstrate that dynamically frozen FWs that we call 2D-hydrodynamic crystals do appear as ordered patterns of nonlinear surface modes in water surfaces functionalized with soluble (bio)surfactants endowing in-plane shear stiffness. The strong phase coherence in conjunction with the increased surface rigidity bear the FW-ordering transition, upon which the hydrodynamic crystals were reversibly molded by parametric control of their degree of order. Crystal symmetry and unit cell size were tuned depending on the FW-dispersion regime. The hydrodynamic crystals here discovered could be exploited in touchless strategies of soft matter scaffolding. Particularly, the surface-directed synthesis of structured materials based on colloids or polymers and cell culture patterns for tissue engineering could be ameliorated under external control of FW-coherence

cond-mat.soft↗