Localization Counteracts Decoherence in Noisy Floquet Topological Chains.

Area of Science:

• Condensed matter physics
• Quantum mechanics
• Topological phases

Background:

• Topological phases in periodically driven (Floquet) systems require perfect time-periodicity.
• Deviations from periodicity cause decoherence, leading to the leakage of boundary (end) states into the bulk.

Purpose of the Study:

• To investigate how the nature of bulk states influences the decay of topologically protected end states in one-dimensional Floquet systems.
• To explore the role of disorder in counteracting decoherence and protecting topological phases.

Main Methods:

• Analytical derivation using a novel, discrete-time Floquet-Lindblad formalism.
• Numerical simulations to confirm analytical findings.

Main Results:

• The decay rate of topologically protected end states depends on bulk state localization.
• Dispersive bulk states lead to exponential decay, while localized bulk states result in diffusive decay.
• Disorder can localize bulk states, slowing decay and counteracting decoherence, even when breaking protective symmetries.

Conclusions:

• Disorder can be a crucial resource for protecting Floquet topological phases from decoherence in experimental settings.
• Tailoring disorder offers a pathway to enhance the stability of topological states in driven quantum systems.