Non-Hermitian Floquet Phases with Even-Integer Topological Invariants in a Periodically Quenched Two-Leg Ladder

Area of Science:

• Condensed Matter Physics
• Quantum Dynamics
• Topological Matter

Background:

• Periodically driven non-Hermitian systems exhibit unique nonequilibrium phases.
• These systems possess exotic topological, dynamical, and transport properties.

Purpose of the Study:

• Introduce an experimentally realizable two-leg ladder model with time-periodic quenches and non-Hermitian effects.
• Explore the emergence of non-Hermitian Floquet topological phases in the extended CII symmetry class.

Main Methods:

• Utilized a two-leg ladder model subjected to time-periodic quenches and non-reciprocity.
• Characterized emergent phases by a pair of even-integer topological invariants (w0, wπ).
• Investigated edge localization of zero- and π-quasienergy modes under open boundary conditions.

Main Results:

• Identified rich non-Hermitian Floquet topological phases due to the interplay of driving and nonreciprocity.
• Topological invariants (w0, wπ) ∈ 2Z × 2Z characterize these phases.
• Developed a generalized mean chiral displacement as a dynamical probe for topological invariants.

Conclusions:

• Introduced a novel class of non-Hermitian Floquet topological matter.
• Demonstrated the richness of topology and dynamics in driven open systems.
• Highlighted the potential of mean chiral displacement for probing topological properties.