Optical control over correlated topological quantum phases of matter

A central goal in modern condensed matter physics is to understand and manipulate collective phenomena at the intersection of topology and strong many-body interactions. Moire materials composed of layered van der Waals (vdW) crystals are a unique platform for exploring this frontier. These systems support flat topological electronic bands resembling Landau levels but without magnetic fields. This has recently enabled realization of long-sought fractional Chern insulators (FCIs): zero-field analogs of fractional quantum Hall (FQH) states. Unlike the latter, FCIs operate in an unexplored regime where electrons spontaneously break time-reversal symmetry and experience emergent magnetic fields far exceeding those in standard laboratories. This raises timely fundamental questions: What is the nature of collective fractionally charged excitations of FCIs? Can they couple to light? Can we engineer vdW devices that allow for in-situ programming of FCI properties with light, a feat impossible for FQH? Addressing these questions could have revolutionary implications, unlocking dynamical access to the phase diagrams of topologically-ordered phases, a key challenge in the field.The overarching goal of this project is to develop an optical interface that enables local, on-demand, ultra-fast access and control over strongly correlated topological phases in moire materials. Using this platform, we will answer key questions of topological many-body physics, with potential groundbreaking technological applications in topotronics and quantum computing.