Alfred Zong

Phase transitions instigated by an intense, ultrashort laser pulse usher in a new era for engineering quantum materials at the femto 10^-15 to picosecond 10^-12s timescales. In this talk, I will discuss two important pathways for manipulating non-equilibrium phases of matter that feature competing orders and strong electronic interactions. More specifically, an ultrashort light pulse can unleash a hidden order that is suppressed in equilibrium due to phase competition and change the dimensionality of an ordered state by modifying excitonic correlations. I will explain the microscopic mechanisms behind these unconventional light induced states highlighting the roles of photoinduced topological defects, order parameter fluctuation, and carrier screening. These points will be discussed using examples from materials that exhibit a charge density wave and a spontaneous formation of electron density modulation accompanied by a periodic lattice distortion which serves as a versatile model system to illustrate general principles underlying ultrafast light-matter interaction in strongly correlated materials.