Abstract
Creating stable superposed states of matter is one of the most intriguing aspects of quantum physics, leading to a variety of counter-intuitive scenarios along with a possibility of restructuring the way we understand, process and communicate information. Accordingly, there has been a major research thrust in understanding and quantifying such coherent superposed states. Here we propose and experimentally explore a quantifier that captures effective coherent superposition of states in an atomic ensemble at room-temperature. The quantifier provides a direct measure of ground state coherence for electromagnetically induced transparency (EIT) along with distinct signature of transition from EIT to Autler-Townes splitting (ATS) regime in the ensemble. Using the quantifier as an indicator, we further demonstrate a mechanism to coherently control and freeze coherence by introducing an active decay compensation channel. In the growing pursuit of quantum systems at room-temperature, our results provide a unique way to phenomenologically quantify and coherently control coherence in atom-like systems.
Highlights
Creating stable superposed states of matter is one of the most intriguing aspects of quantum physics, leading to a variety of counter-intuitive scenarios along with a possibility of restructuring the way we understand, process and communicate information
A widely used technique to generate superposed states in atomlike systems [22, 23] is based on the phenomenon of electromagnetically induced transparency(EIT) [14,15,16,17], where a strong control field is used to drive an effective three level atomic system into a particular coherent superposition of ground-state sub-levels (|1 and |2, Fig. 1a), known as dark state, in presence of a weak probe field
To conclude here we have demonstrated a phenomenological quantifier for ground state coherence in an atomic ensemble for EIT at room-temperature
Summary
To conclude here we have demonstrated a phenomenological quantifier for ground state coherence in an atomic ensemble for EIT at room-temperature. & Polzik, E.S. Quantum interface between light and atomic ensembles. & Lukin, M.D. Dark-state polaritons in electromagnetically induced transparency. & Marangos, J.P. Electromagnetically induced transparency: Optics in coherent media. Stopped light and image storage by electromagnetically induced transparency up to the regime of one minute. Quantum nonlinear optics with single photons enabled by strongly interacting atoms. Induced transparency in mechanical effects of light. Storage and retrieval of time-bin qubits with photon-echo-based quantum memories. [44] Yang, L., Zhang, L., Li, X., Han, L., Fu, G., Manson, N.B., Suter, D. Autler-Townes effect in a strongly driven electromagnetically induced transparency resonance. & Scully, M.O. Quantum interference effects induced by interacting dark resonances. [49] Zhao, R., Dudin, Y.O., Jenkins, S.D., Campbell, C.J., Matsukevich, D.N., Kennedy, T.A.B.
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