Abstract
We report the first direct observation of an exceptional point (EP) in an open quantum composite of a single atom and a high-Q cavity mode. The atom-cavity coupling constant was made a continuous variable by utilizing the multisublevel nature of a single rubidium atom when it is optimally coupled to the cavity mode. The spectroscopic properties of quasieigenstates of the atom-cavity composite were experimentally investigated near the EP. Branch-point singularity of quasieigenenergies was observed and its 4π symmetry was demonstrated. Consequently, the cavity transmission at the quasieigenstate was observed to exhibit a critical behavior at the EP.
Original language | English |
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Article number | 153601 |
Journal | Physical review letters |
Volume | 104 |
Issue number | 15 |
DOIs | |
Publication status | Published - 2010 Apr 13 |
ASJC Scopus subject areas
- Physics and Astronomy(all)