Non-Floquet engineering in periodically driven dissipative open quantum systems.

Area of Science:

• Quantum physics
• Condensed matter physics
• Topological states of matter

Background:

• Floquet engineering is crucial for dynamical topological states but limited to non-dissipative Hermitian systems.
• Open quantum systems often exhibit non-Hermitian processes, complicating topological phase characterization.
• Characterizing topological phases in time-periodic open quantum systems using Floquet Hamiltonians is an open challenge.

Purpose of the Study:

• To develop a theoretical framework for characterizing topological phases in time-periodic open quantum systems.
• To extend the understanding of Floquet engineering to non-Hermitian and dissipative systems.
• To explore the design of quantum detectors for topological phases in dissipative oscillating fields.

Main Methods:

• Proposing and applying the non-Floquet theory to continuously time-periodic non-Hermitian bipartite chains.
• Utilizing a temporal non-unitary transformation on Floquet states.
• Analyzing the resulting Floquet spectrum and localization behavior.

Main Results:

• The non-Floquet theory transforms the Floquet spectrum into a Wannier-Stark ladder.
• Different driving period start points lead to distinct localization behaviors.
• Demonstrated the potential for designing quantum detectors of phases in dissipative oscillating fields.

Conclusions:

• The non-Floquet theory provides a robust method for describing topological features in dynamical open quantum systems.
• This approach is applicable to various driving types and can aid in constructing novel dynamical topological materials.
• The findings open new avenues for exploring topological phenomena in open quantum systems.