Nonclassicality in off-resonant Raman process

Abstract

Raman process is used for generation of nonclassical states and subsequent applications due to its simplicity. In view of the experimental feasibility of the off-resonant Raman process at single photon level useful in long distance quantum communication and quantum memory, we perform here a detailed study of possibility of generation of nonclassical states under off-resonance conditions. Specifically, we have studied nonclassicality in the off-resonant Raman process with the help of a characteristic function written using more general solution than the conventional short-time solution under complete quantum treatment and established the significance of frequency detuning parameter in generation of nonclassical states. The obtained characteristic function remains Gaussian and reveals that larger values of frequency detuning parameters are favorable to induce nonclassicality in some cases. The single-and two-mode squeezing and antibunching as well as intermodal entanglement are reported in terms of experimentally accessible quantum noise fluctuations considering either phonon mode coherent or chaotic. Subsequently, the joint photon number and integrated intensity distributions are studied to analyze the performance of pair generation in Stokes-phonon and pump-phonon modes. The present study discusses the role of resonance conditions in generation of nonclassical states and establishes that experimentally controllable detuning parameter can be used to probe and enhance the generated nonclassicality. arXiv:1812.08264v1 [quant-ph]

Interplay between quantum Zeno and anti-Zeno effects in a nondegenerate hyper-Raman nonlinear optical coupler

“…Further extension of the present results with phonon mode initially coherent to the chaotic phonon mode [38] gives that all the Zeno parameters become zero. Our results can also be used to deduce the presence of QZE and QAZE for degenerate hyper-Raman and Raman system waveguides from Eqs.…”

“…where i = 1 for j = d and i = 2 for j = b. It clearly shows that the general solution used here is modulated with sinc function of the frequency detuning parameter [38,39]. Consequently, the present solution and corresponding results are applicable to a relatively long length of the optical coupler in comparison to the corresponding short-length solution.…”

Quasidistribution of phases in Raman process with weak and strong pumps

“…Our suggestion of the interference experiment [12] for obtaining the presented nonclassical phase effects has to follow such conditions. In the present case, the obtained quantum noise function terms are as follows [13] B L (t) = 2|χ| 2 |ξ A | 2 (1−cos δit) δ 2…”

“…The perturbative analytic form of quantum noise terms in the characteristic function (2) in this case is reported in Appendix A. We are interested in the offresonant Raman process [13] where the dynamics is dependent upon two frequency detuning parameters, particularly ∆ω 1 = (ω S + ω V − ω L ) and ∆ω 2 = (ω L + ω V − ω A ) as detuning parameters in Stokes and anti-Stokes generation processes, respectively. Here, ω L , ω S , ω A , and ω V correspond to pump, Stokes, anti-Stokes, and phonon mode frequencies, respectively.…”

Ideal pairing of the Stokes and anti-Stokes photons in the Raman process

“…The quantum theory of the Raman process was introduced in [16] and the generation of several types of the nonclassical states was discussed over the time (for the review, see [17,18]). Recently, the correlations between the optical and phonon modes both at resonance and out-of resonance, as well as the generalization of the Raman process to the hyper-Raman process have been investigated [19][20][21]. The fields in the Raman process were experimentally investigated in inelastic scattering of the laser light from water [22], Rb vapors [23] and diamond [24].…”