We propose a theoretical method to enhance the coherent dipole coupling between two atoms in an optical cavity via parametrically squeezing the cavity mode. In the present scheme, conditions for coherent coupling are derived in detail and diverse dynamics of the system can be obtained by regulating system parameters. In the presence of environmental noise, an auxiliary squeezed field is employed to suppress, and even completely eliminate the additional noise induced by squeezing. In addition, we demonstrate that our scheme enables the effective suppression of atomic spontaneous emission. The results in our investigation could be used for diverse applications in quantum technologies. *

We propose a one-step scheme for driving many atoms into a NOON state. In this scheme, two cavities are coupled to each other through the photon-hopping interaction and each cavity contains N four-level atoms. The 2N atoms are driven into a NOON state via a phase-shift which depends on the collective atomic excitations. Interestingly, the time of generating the NOON state is independent of the atom number, i.e., it is unchanged with the increasing of the atom number. Also, our scheme is insensitive to cavity decay and can effectively suppress atomic spontaneous emission.

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We study the effects of dissipation induced blockade on the dynamics of an open quantum system having two qubits in nonequilibrium independent baths. The qubits are driven by a classical field with a temporally modulated detuning. The introduction of blockade induced via two effective baths together with the effect of the driving field enable us to observe maximal entanglement oscillation of about unity that decays with a quasi-steady entanglement state oscillating about the 1/2 limit with adjustable decay rate. When the temperature difference between two baths is not large, maximal entanglement oscillation can still be observed in the model. In addition, the adjustment of the nonequilibrium thermal baths by modulating the dissipation and the application of time-dependent detuning give rise to rich entanglement dynamics. We further demonstrate numerically the practical implementation of the proposed scheme with a universal cavity QED setting.