Direct Manipulation of Biphoton Generation From the non-Hermitian Nature of Light-matter Interaction

While biphoton generation holds significant importance in quantum entanglement and quantum technology, its dynamics involving non-Hermitian characteristics have experimentally been untouched so far. Nevertheless, it is found that the non-Hermitian features induced by the atomic coherence can be well employed for the direct control of biphoton generation and entanglement. By harnessing such natural non-Hermitian interaction, a method is devised to expand a non-Hermitian Hao biphoton generation processes. It is experimentally demonstrated such biphoton correlation can be adjusted within an unprecedentedly wide range, ranging from Rabi oscillation to antibunching-exponential-decay. Typically, the exceptional point at the transition boundary between the two regimes is distinctly observed.