Resilience and fragility of two-dimensional active crystals
Resilience and fragility of two-dimensional active crystals
- Event time: 3:00pm until 4:00pm
- Event date: 9th January 2024
- Speaker: Hugues Chate (CEA-Saclay, Paris)
- Location: Online - see email.
Event details
The Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) theory of melting is a much-admired result that revealed that equilibrium 2D crystals can melt into in two successive KT-like transitions leading to liquid state. A well-known result of KTHNY is to predict an upper bound $\frac{1}{3}$ to the spin wave exponent $\eta$ governing the algebraic decay of the two-point correlation function of positional order in the crystal phase. Whereas this result is often used in equilibrium to decide to decide whether a crystal has melted, it has been claimed (or assumed) to apply also for crystals made of active units, which are intrinsically out of equilibrium.
I will show that such active crystals are not subjected to the KTHNY bound $\eta< \frac{1}{3}$. They can be either more resilient to fluctuations without melting ($\eta> \frac{1}{3}$), or more fragile and break for $\eta< \frac{1}{3}$. These results are rationalized within linear elastic theory in terms of two well-defined effective temperatures governing respectively large scale positional deformations and short scale bond-order fluctuations.
About Statistical Physics and Complexity Group meetings
This is a weekly series of webinars on theoretical aspects of Condensed Matter, Biological, and Statistical Physics. It is open to anyone interested in research in these areas..
Find out more about Statistical Physics and Complexity Group meetings.