ELFT HÍRADÓ

[Janos Asboth <asboth AT phy.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

február 19. péntek 10h15,
online a Microsoft Teams-ben
<https://teams.microsoft.com/l/meetup-join/19%3a35c712c192104aa998ed6bab3f0cbc07%40thread.tacv2/1613588209922?context=%7b%22Tid%22%3a%226a3548ab-7570-4271-91a8-58da00697029%22%2c%22Oid%22%3a%22c7eaf7d2-684b-4597-b217-6a9121400219%22%7d>
Asbóth János (BME Elméleti Fizika Tanszék, Wigner FK):
Anomalous Levitation and Annihilation in Floquet Topological Insulators

Recently, the anomalous Floquet Anderson insulator (AFAI) has attracted
significant attention due to the coexistence of chiral edge modes and fully
localized bulk. We show[1] that an AFAI can be obtained by
time-periodically applying disordered phase "kicks" (via onsite potential)
to a clean Chern insulator, a next-nearest neighbor hopping Hamiltonian
with staggered flux. By computing the transmission through the system, we
find that tuning the time period between the kicks leads to AFAI phases
with different topological invariants, even in the limit of complete
disorder (uniformly distributed phases). Disorder-induced transitions to
these phases occur by "levitation and pair annihilation" of extended states
carrying the Chern numbers, but these transitions can be anomalous, with
the two annihilating states coming from different Floquet zones. Our
results are applicable to a variety of Floquet topological systems, and may
provide a more accessible way to construct AFAIs in cold-atom experiments.

[1]: H Liu, IC Fulga, J.K. Asboth, Phys. Rev. Research 2, 022048(R),
arXiv:2003.02266

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Asbóth János
szemináriumi koordinátor