English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We construct a systematic high-frequency expansion for periodically drivenquantum systems based on the Brillouin-Wigner (BW) perturbation theory, whichgenerates an effective Hamiltonian on the projected zero-photon subspace in theFloquet theory, reproducing the quasienergies and eigenstates of the originalFloquet Hamiltonian up to desired order in $1/\omega$, with $\omega$ being thefrequency of the drive. The advantage of the BW method is that it is not onlyefficient in deriving higher-order terms, but even enables us to write down thewhole infinite series expansion, as compared to the van Vleck degenerateperturbation theory. The expansion is also free from a spurious dependence onthe driving phase, which has been an obstacle in the Floquet-Magnus expansion.We apply the BW expansion to various models of noninteracting electrons drivenby circularly polarized light. As the amplitude of the light is increased, thesystem undergoes a series of Floquet topological-to-topological phasetransitions, whose phase boundary in the high-frequency regime is wellexplained by the BW expansion. As the frequency is lowered, the high-frequencyexpansion breaks down at some point due to band touching with nonzero-photonsectors, where we find numerically even more intricate and richer Floquettopological phases spring out. We have then analyzed, with the Floquetdynamical mean-field theory, the effects of electron-electron interaction andenergy dissipation. We have specifically revealed that phase transitions fromFloquet-topological to Mott insulators emerge, where the phase boundaries canagain be captured with the high-frequency expansion.

Brillouin-Wigner theory for high-frequency expansion in periodically driven systems: Application to Floquet topological insulators