We propose a dissipative scheme to prepare maximally entangled steady states in cavity QED setup, consisting of two two-level atoms interacting with the two counter-propagating whispering-gallery modes (WGMs) of a microtoroidal resonator. Using spontaneous emission and cavity decay as the dissipative quantum dynamical source, we show that the steady state of this system can be steered into a two-atom single state as well as into a two-mode single state. We probed the compound system with weak field coupled to the system via a tapered fiber waveguide, finding it is possible to determine whether the two atoms or two modes are driven to a maximally entangled state. Through the transmission and reflection measurements, without disturbing the atomic state, when the cavity modes are being driven, or without disturbing the cavity field state, when a single atom being driven, one can get the information about the maximal entanglement. We also investigated for both subsystem, two-atom and two-mode states, the entanglement generation and under what conditions one can transfer entanglement from one subsystem to the other. Our scheme can be selectively used to prepare both maximally entangled atomic state as well as maximally entangled cavity-modes state, providing an efficient method for quantum information processing.

We investigate the entanglement dynamics of a system comprising a pair of two-leveldipole-dipole interacting atoms coupled to a microtoroidal resonator. Each atom is individuallycoupled with the two counter-propagating whispering gallery modes of the resonator through theirevanescent fields. The atom-atom entanglement shown for several parameter sets of the system wasobtained using the negativity. For ideal resonators, it is seen that the entanglement is correlated tothe dipole-dipole interaction and the average number of photons when the modes of the resonatorare prepared in a thermal state even at high temperatures. Further, for the non-ideal resonator case,where there is a small structural deformation of the microtoroidal structure that allows a directcoupling between the modes, a counter-intuitive result is presented. The imperfections also offerthe advantage of generating maximally entangled states for a two-atom subsystem with maximumfidelity.

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