Quantum Matter Seminar

A plethora of correlated many-body ground states have been reported in flatband graphene systems. However, the dynamics and excitations associated with these correlated states, crucial for understanding the underlying physics, remain unexplored. In this talk, I will discuss our recent efforts in investigating dynamics of isospin orders in flatband graphene systems by combining exciton sensing and optical pump-probe spectroscopies. With the capabilities of tracking melting and recovery of isospin orders at sub-picosecond resolution, we unveil the presence of abnormally long-lived isospin modes in magic-angle twisted bilayer graphene (MATBG) that decouple from the much faster cooling of electronic temperature, implying strong isospin fluctuations. We further demonstrate ultrafast control of the isospin orders, paving the way for actively controlling non-equilibrium phenomena in moiré systems.\