Intermodal entanglement in Raman processes

Abstract

The operator solution of a completely quantum mechanical Hamiltonian of the Raman processes is used here to investigate the possibility of obtaining intermodal entanglement between different modes involved in the Raman processes (e.g. pump mode, Stokes mode, vibration (phonon) mode and anti-Stokes mode). Intermodal entanglement is reported between a) pump mode and anti-Stokes mode, b) pump mode and vibration (phonon) mode c) Stokes mode and vibration phonon mode, d) Stokes mode and anti-stokes mode in the stimulated Raman processes for the variation of the phase angle of complex eigenvalue α1 of pump mode a. Some incidents of intermodal entanglement in the spontaneous and the partially spontaneous Raman processes are also reported. Further it is shown that the specific choice of coupling constants may produce genuine entanglement among Stokes mode, anti-Stokes mode and vibration-phonon mode. It is also shown that the two mode entanglement not identified by Duan's criterion may be identified by Hillery-Zubairy criteria. It is further shown that intermodal entanglement, intermodal antibunching and intermodal squeezing are independent phenomena.

Nonclassical properties of a contradirectional nonlinear optical coupler

“…Study of the possibility of generation of nonclassical states (specially, entanglement and nonlocal characters of quantum states) in different quantum systems have recently become extremely relevant and important for the researchers working in different aspects of quantum information theory and quantum optics. Existence of entanglement and other nonclassical states in a large number of bosonic systems has already been reported (see [8][9][10] and references therein). However, it is still interesting to study the possibility of generation of nonclassical states in experimentally realizable simple systems.…”

Single-mode and intermodal higher-order nonclassicalities in two-mode Bose-Einstein condensates

“…The inclusion of these extra terms makes a solution obtained using this method more powerful than a usual short-time approximated solution in detecting nonclassicality. This fact is established in our earlier works [35][36][37][38][39]. (4) where G(t) = (1 − e −i μt ).…”

“…There exist several sufficient inseparability criteria. However, we restrict ourselves to these three criteria as they have recently been found successful in detecting intermodal entanglement in other bosonic systems [21,28,39]. The first inseparability criterion of Hillary and Zubairy, i.e., HZ-1 criterion, is…”

“…Here we use the perturbative solutions which are more general than the well known short-time approximation [19]. The technique used here is available in our previous papers [35][36][37][38][39]. 1 The solutions of Eqs.…”

“…Equations of motion corresponding to a two-mode BEC Hamiltonian can be solved by using different methods, such as the short-time approximation, Gross-Pitaevskii approximation, Bethe ansatz method, etc. In the present work a secondorder analytic operator solution of the generalized Hamiltonian is obtained using a technique developed by some of the present authors [35][36][37][38][39]. The solutions obtained as time evolution of annihilation and creation operators of different modes are subsequently used to show different signatures of lower-order and higher-order nonclassicality in two-mode BECs.…”