Time: 2:00 pm

Venue: LeConte 402

Title: Criticality and universality of Floquet topological phase transitions

Abstract: Periodic driving has recently emerged as an extremely versatile tool to engineer and tune exotic topological states of matter in a controlled

way. For example, periodic driving generates a cascade of Majorana edge

modes beyond the static limitation of one per edge in the Kitaev chain,

resulting in a hierarchy of associated topological phase transitions

(TPT’s). Understanding the critical behavior of such out-of-equilibrium

TPT’s is therefore an important step in the quest to harness the unique

properties of Floquet systems.

In this talk, I will compare the nature of the topological phase

transitions in various static and periodically driven systems by means

of a renormalization group procedure on the curvature functions used to

construct topological invariants. I will demonstrate how this very

transparent and powerful method can identify the topological phase

boundaries and assess the nature of their criticality in terms of

universality classes. This procedure works even for topological phases

hosting anomalous edge modes, i.e. phases where the Floquet band Chern

number does not correspond to the number of edge states. Finally, I will

also show how the method can be effectively extended to explicitly

time-dependent curvature functions to capture the critical behavior as a

function of time.