Abstract
We show that microwave-driven NV centers can function as topological mode switches by utilizing a special degeneracy called an exceptional point (EP). By tuning the intensities and frequencies of the driving fields, we find an EP---where two normal modes of the system coalesce---and, then, use it to simulate the dynamics and demonstrate topological and non-reciprocal mode switching. By comparing density matrices of the input and output states, we find that the quantum correlations decrease by three orders of magnitude at room temperature, and discuss ways for improving this result. This work extends the theory of topological mode switches (originally derived for pure states) to mixed states and is, therefore, applicable to general open quantum systems. Our theory enables exploring new phenomena (e.g., high-order EPs in low-dimensional systems) and presents a crucial step towards incorporating topological mode switches in quantum-information applications.
Highlights
A new class of adiabatic protocols enables robust mode conversion in open systems that possess a special degeneracy called an exceptional point (EP), where multiple modes of the system coalesce [1,2,3]
We show that microwave-driven NV centers can function as robust mode switches by utilizing a special degeneracy called an exceptional point (EP)
While previous theoretical and experimental work on EP-based mode switches applies only to pure states, we develop here a general theory for switching between mixed states, statistical ensembles of different pure states, resulting from the interaction with the environment
Summary
A new class of adiabatic protocols enables robust mode conversion in open systems that possess a special degeneracy called an exceptional point (EP), where multiple modes of the system coalesce [1,2,3]. Robust mode switches are based on the adiabatic theorem, which describes the evolution of slowly varying closed systems. The theorem states that when preparing a system in a particular eigenmode, it remains in that mode during the evolution
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