Coral Biophysics

• Coral motion

Coral reefs harbor great biodiversity, support 25% of all marine life and hold immense ecological and economic value. Reef-building corals are inherently sessile organisms, however, motion is an important behavioral trait of coral. Motions of tissues, polyps and tentacles play essential roles in feeding, competition, defense, reproduction, and thus survival and fitness. Notwithstanding the importance of inherent temporal and spatial multi-scale features of polyps, its quantitative properties and modelling still remain challenging and unexplored. We use the long-period observation, numerical analysis and theoretical modelling to describe and understand the coral motion biologically and physically.

• Coral bleaching

Coral bleaching is a biological phenomenon threatening the existence of coral reefs and presenting a major global challenge for the scientific community. It describes the expulsion of symbiotic algae causing scleractinian corals to appear white as the skeleton can be seen through the transparent tissue. However, high frequency photographic observations and tissue color quantifications are limited. We use the long-period observation and mathematical tools to understand the coral bleaching quantitatively.

• Coral wound healing

Reef-building corals, as keystone organisms, supports coral-reef ecosystems and related biological activities. They are composed of coral organisms living in symbiosis with photosynthetic dinoflagellate algae and a complex bacterial community. Coral reefs have experienced continuous decline due to disease outbreaks including the wounds on the body boosted by high seawater temperatures and fragilized corals from heat stress and potential bleaching onset. Facilitating the wound healing and understanding the healing process physically are crucial for protecting corals in the future changing environment.

Soft Topological Metamaterials

• Topological interface states

Topological elastic metamaterials offer insight into classic motion law and open up opportunities in quantum and classic information processing. Topologically protected wave propagation possesses prominent applications in quantum computation and communication field due to its remarkable characteristic: the robust defect-immune transport. Recently, significant research efforts devoted in phononic topological insulators provide a new way to manipulate sound propagation, such as vibration isolation and particle manipulation. Soft materials are capable of deformation so that they prossess a large tunability. The combination of soft materials with high-frequency topological states offers unprecedented opportunities, which requires insight exploration. We design a soft metamaterial with honeycomb pattern with reversible topological phase and dynamically tunable topological states.

• Topological valley states

Recently, valley—the degenerate yet inequivalent energy extrema in momentum space— has emerged as a dimension in manipulating waves in electronics, photonics, and phononics. In graphene and transition metal dichalcogenides (TMD), the valley Hall effect has been studied for the promising applications in information carrier and storage. As the concept of valley is introduced into the classic system, the photonic and phononic valley crystals have also been proposed, showing valley-dependent energy transportation. Likewise, various designs of elastic valley metamaterials have been reported based largely on the two different types: TMD-inspired hexagonal lattices, and triangular lattices with triangle-like scatterers. We design a novel spiral elastic valley metamaterials by introducing the combination of soft matrix and hard spiral, which is able to have topological transition and propagation of topological valley states.