Loss-induced universal one-way transport in periodically driven systems

Recent studies on the non-Hermitian skin effect have introduced a novel approach to achieve one-way transport by leveraging the disparate lifetimes of forward and backward propagating channels. While theoretically sound, it was previously believed that implementing such non-reciprocal transport would require complex elements like non-reciprocal tunneling, posing substantial challenges for experimental realization. In this talk, we show that a periodically driven Aubry-André-Harper model with imbalanced onsite gain/loss supports universal one-way transport that is immune to impurities and independent of initial excitations. We reveal the underlying mechanism that the periodic driving gives rise to the non-Hermitian skin effect in the effective Floquet Hamiltonian, thereby causing universal non-reciprocal transport. Remarkably, in contrast to the conventional non-Hermitian skin effect, which is complex and challenging to realize, we find that one-way transport via the Floquet emergent non-Hermitian skin effect can be easily achieved within existing experimental setups (e.g., acoustic sound waves [Phys. Rev. Lett. 125, 224301 (2020)]). Additionally, we probe the Lyapunov exponent under long-time dynamics as a signature of the Floquet emergent non-Hermitian skin effect. Our results provide a feasible and controllable way to realize universal one-way transport that is easily accessible to experiments.