Control of a Nonlocal Entanglement in the Micromaser via Two Quanta Non-Linear Processes Induced by Dynamic Stark Shift

Abstract

We show that, under certain conditions, the micromaser can act as an effective source of highly correlated atoms. It is possible to create an extended robust entanglement between two successive, initially unentangled atoms passing through a cavity filled with a nonlinear medium taking into consideration a slight level shift. Information is transfered from the cavity to the atoms in order to build up entanglement. The scheme has an advantage over conventional creation of entanglement if the two atoms (qubits) are so far apart that a direct interaction is difficult to achieve. The interaction of the atoms with the micromaser occurs under the influence of a two-quantum transition process. Interesting phenomena are observed, and an extended robust entangled state is obtained for different values of the system parameters. Illustrative variational calculations are performed to demonstrate the effect within an analytically tractable two-qubit model.

Entanglement Dynamics and Spin-Squeezing of the Nonlinear Tavis–cummings Model Mediated by a Nonlinear Binomial Field

“…The close relation between the entanglement and spin squeezing enhances the importance of spin squeezing which motivate us to explore the role of Kerr medium [38][39][40][41] and the nonlinear binomial state on the spin squeezing and entanglement.…”

“…We denote by χ the dispersive part of the third order susceptibility of the Kerr-like medium [38][39][40][41]. The parameter λ represents the atoms-field coupling constant.…”

“…Wang and Sanders [37], presented a generalization of the results of Ref.[28] to the multiqubit case, where the authors showed that spin squeezing implies pairwise entanglement for arbitrary symmetric multiqubit states. More quantitatively, for spin states with a certain parity, if a state is spin squeezed according to the definition for Kitagawa and Ueda [15], a quantitative relation is obtained between the spin squeezing parameter and the concurrence [42][43][44][45], quantifying the entanglement of two half-spin particles [28,37].The close relation between the entanglement and spin squeezing enhances the importance of spin squeezing which motivate us to explore the role of Kerr medium [38][39][40][41] and the nonlinear binomial state on the spin squeezing and entanglement.A binomial state is one of the important nonclassical states of light which has attracted much attention in the field of quantum optics in the last few decades, see for example [46][47][48]. This, in fact, is due to the importance of these states which have been experimentally produced and characterized.…”

An Investigation of a Nonlocal Entanglement of Two Uncoupled Atoms Embedded in a Coherent Cavity Field and the Associated Phase Space Distribution: One Quantum Nonlinear Process

“…where a ( a † ) is bosonic annihilation (creation) operator for the single mode field of frequency ω and λ is atoms-field coupling constant, the operators σ + = |+ −| , σ − = |− +| and σ z = |+ +| − |− −| represent, respectively, the raising, lowering and population atomic operators which obey the commutation relations [ σ + , σ − ] = σ z , while ∆ = ω 0 − ω is the detuning parameter which represents the difference between the atomic and cavity subsystems eigenfrequencies. We denote by χ the dispersive part of the third order susceptibility of the Kerr-like medium [15,16,20,[29][30][31].…”

“…Particular and great interest is devoted to the generation of entangled states in two-atom systems, since they can represent two qubits that considered the base blocks of building the quantum gates that are essential to implement various quantum protocols. Furthermore, there have been many proposals for generating atomic entanglement and entanglement between cavity modes through atom-photon interaction [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Some notable experimental demonstrations have also been performed [17].…”