Wigner-Yanse skew information of the system with the electromagnetically induced transparency

Abstract

The quantum-information theoretic notation of the Winger-Yanse skew information has been used to analyze the process of information transfer between probe fields and atomic ensemble in the electromagnetically induced transparency. It is well known that the skew information is a well-defined measure that quantifies the amount of the information a quantum state contains. We have calculated the dynamical skew information of the probe fields and the atomic ensemble, and found that the information for the individual atom is dependent of the numbers of the particles and the photons, as well as the state of the probe field. For a sufficiently weak coherent driving field, the dark-state polaritons is a purely atomic state with no photons in the composite system, and the information of the individual atom reaches the maximum value. However, the information of the probe field is not completely transferred into the atomic ensemble.