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We have experimentally studied propagation of two optical fields in a dense rubidium (Rb) vapor in the case when an additional microwave field is coupled to the hyperfine levels of Rb atoms. The Rb energy levels form a close-lambda…
Electromagnetically-induced transparency has become an important tool to control the optical properties of dense media. However, in a broad class of systems, the interplay between inhomogeneous broadening and the existence of several…
In contrast to the general thought that the collisions are intrinsically dephasing in nature and detrimental to quantum entanglement at room or higher temperatures, here, we show that in the conventional ladder-type three-level…
We report characterization of electromagnetically induced transparency (EIT) resonances in the D1 line of Rb-87 under various experimental conditions. The dependence of the EIT linewidth on the power of the pump field was investigated, at…
We report electromagnetically induced transparency (EIT) in cold 85Rb atoms, trapped in the lower hyperfine level F = 2, of the ground state 5$^{2}S_{1/2}$ (Tiwari V B \textit{et al} 2008 {\it Phys. Rev.} A {\bf 78} 063421). Two steady…
We present a realistic theoretical treatment of a three-level $\Lambda$ system in a hot atomic vapor interacting with a coupling and a probe field of arbitrary strengths, leading to electromagnetically-induced transparency and slow light…
Two-photon processes that involve different sub-levels of the ground state of an atom, are highly sensitive to depopulation and decoherence within the ground state. For example, the spectral width of electromagnetically induced transparency…
We investigate how the interplay between a staggered magnetic field and staggered coupling strength affects both ground state and thermal entanglement. Upon analytically calculating thermodynamic quantities and the correlation functions for…
Electromagnetically induced transparency (EIT) has mainly been modelled for three-level systems. In particular, a considerable interest has been dedicated to the Lambda-configuration, with two ground states and one excited state. However,…
We study the effect of a DC magnetic field on the phase sensitivity of a double-lambda system coupled by two laser fields, a probe and a pump. It is demonstrated that the gain and the refractive index of the probe can be controlled by…
We show that an alkali atom with a tripod electronic structure can yield rich electromagnetically induced transparency phenomena even at room temperature. In particular we introduce double-double electromagnetically induced transparency…
We have studied the effects of loading $^{87}$Rb into a far off resonant trap (FORT) in the presence of an ultracold cloud of $^{85}$Rb. The presence of the $^{85}$Rb resulted in a marked decrease of the $^{87}$Rb load rate. This decrease…
We examine electromagnetically induced transparency (EIT) in an ensemble of cold $\Lambda-$type atoms induced by a quantum control field in multi-mode coherent states and compare it with the transparency created by the classical light of…
Cavity electromechanics relies on parametric coupling between microwave and mechanical modes to manipulate the mechanical quantum state, and provide a coherent interface between different parts of hybrid quantum systems. High coherence of…
We present a theoretical model, using density matrix approach, to study the effect of weak as well as strong probe field on the optical properties of an inhomogeneously broadened multilevel V-system of the $^{87}$Rb D2 line. We consider the…
We study the effect of an external magnetic field on coherent backscattering of light from a cool rubidium vapor. We observe that the backscattering enhancement factor can be {\it increased} with $B$. This surprising behavior shows that the…
We report experimental measurements showing how one can combine quantum interference and thermal Doppler shifts at room temperature to detect weak magnetic fields. We pump ${}^{87}$Rb atoms to a highly-excited, Rydberg level using a probe…
We consider finite sized atomic systems with varying number of particles which have dipolar interactions among them and also under the collective driving and dissipative effect of thermal photon environment. Focusing on the simple case of…
In the usual perception, surface superconductivity is associated with the surface nucleation of a superconducting condensate above the upper critical field in type-II superconductors or with a rearrangement of phonon properties and the…
To control and utilize quantum features in small scale for practical applications such as quantum transport, it is crucial to gain deep understanding of quantum characteristics of states such as coherence. Here by introducing a technique…