Yizhi You: Subsystem symmetry enabled HOTI and its topological phase transitions

Yizhi You from Princeton University speaks about "Subsystem symmetry enabled HOTI and its topological phase transitions"

Abstract: In this talk,  I will demonstrate the existence of a 2D topological phase transition between a higher-order topological insulator(HOTI) and a trivial Mott insulator with the same symmetry which invalidate GLW phase transition paradigm. I will present a theory of this quantum critical point driven by the fluctuation and percolation of the domain walls between HOTI and trivial Mott region. Due to the spinon zero modes decorating at the rough corners of the domain wall, its fluctuation triggers a spinon-dipole hopping term with fracton dynamics and the QCP is characterized by a critical dipole liquid theory with subsystem $U(1)$ symmetry and the breakdown of the area law entanglement entropy with $L \ln(L)$ logarithmic correction.