The influence of spontaneously generated coherence on atom-photon entanglement in a Λ-type system with an incoherent pump

Abstract

Abstract:Owing to interference induced by spontaneous emission, the density-matrix equations in a three-level Λ-type system have an additional coherence term, which plays a critical role in modulating the inversionless gain and electromagnetically induced transparency effect. In addition, it is shown that spontaneously generated coherence (SGC) has an effect on the entanglement between an atom and a photon of the coupling laser field by calculating the degree of entanglement (DEM) of the atomic system. In this paper, we investigate the influence of the SGC effect on atom-photon entanglement in a Λ-type system, which generally remains a high entangled state. When an incoherent pump source is introduced, we find that the SGC effect could exert considerable influence on the atom reduced entropy under certain conditions for both transient and steady states. More interestingly, such an incoherent pump field could actively affect the short-time dynamic behaviors of the transient quantum entangled state at a certain range of pump rate as a typical coherent case. PACS

Dephasing Process of a Single Atom Interacting with a Two-Mode Field

“…In this way, the control and manipulation of the decoherence can be exploited to enhance the entanglement between the system and its environment. It is proven that the entanglement of the induced steady state between a two-level atom and its spontaneous emission excitation is manipulated by detuning the intensity and relative phase of the fields [ 49 , 50 , 51 , 52 , 53 , 54 ]. It is worth noting that the hybrid entanglement between a photon and an atom has applications in quantum tools, such as quantum networks [ 55 ], quantum repeater [ 56 , 57 ], and so on.…”

Validating and controlling quantum enhancement against noise by the motion of a qubit

“…In this way, manipulation and control of decoherence can lead to harnessing system-environment entanglement. It has been demonstrated that the induced steady state entanglement between an atom and its spontaneous emission excitation can be controlled by intensity, detuning and relative phase of applied fields [21][22][23][24][25][26]. It is noteworthy that hybrid atom-photon entanglement has found applications in new quantum tools such as quantum repeater [27,28], quantum networks and quantum memories [29].…”

Atom–photon, two-mode entanglement and two-mode squeezing in the presence of cross-Kerr nonlinearity

“…Furthermore, in the context of semi-classical theory of atom-light interaction, it has been shown that the induced steady state entanglement between an atom and its spontaneous emission can be controlled by intensity and detuning parameter of an applied field [23]. It has, also, been demonstrated that the atom-photon entanglement depends on the relative phase of applied fields [24,25] and incoherent driving pump field [26].…”