in this paper we examine the absorption and dispersion properties of a weak probe field via electromagnetically induced transparency (eit) in a four-level system. it is shown that under certain condition, using this model, the absorption cancellation is appeared and the medium becomes transparent to the weak probe field. it will be shown that the controlling of absorption and dispersion spectru...

The rank-k numerical range has a close connection to the construction of quantum error correction code for a noisy quantum channel. For noisy quantum channel, a quantum error correcting code of dimension k exists if and only if the associated joint rank-k numerical range is non-empty. In this paper the notion of joint rank-k numerical range is generalized and some statements of [2011, Generaliz...

A simple semi-phenomenological model, which accurately predicts the dependence of thresholdcurrent for temperature of Resonant-phonon three well quantum cascade laser based on verticaltransitions is offered. We found that, the longitude optical phonon scattering of thermally excitedelectrons is the most important limiting factor for thermal performance of high frequency THz QCLs.In low frequenc...