| * Venue | Media Centre |
| * Speaker | Kishore Thapliyal |
| * Title | Nonclassical states generated in nonlinear processes and state engineering |
| Affiliation | Joint Laboratory of Optics, Faculty of Science, Palacký University, Czech Republic |
| Abstract | Nonclassical states, having negative Glauber-Sudarshan P-function, do not have a classical analogue. These states have paved way for second quantum revolution and photonic quantum technology. Generation of such states in nonlinear optical processes and its challenges will be discussed with an example of Raman process [1]. Specifically, the suitable conditions for Stokes--anti-Stokes photon pair-generation in the Raman process will be discussed elucidating the role of non-zero phonon population and losses as well as coupling strengths. The Stokes--anti-Stokes correlations are characterized using different nonclassicality witnesses and measures, such as sub-shot noise, Cauchy-Schwarz inequality, Gaussian entanglement and steering, Bell nonlocality. Some nonlinear optical processes lead to exceptional singularities in the dynamical evolution. A quantum system operating at its exceptional singularity is a promising candidate for quantum sensing. In this context, multi-mode bosonic systems capable of offering higher-order exceptional singularity will be discussed with specific attention to some existing methods of generating such degeneracies [2]. Prescription for obtaining the higher-order exceptional singularity in higher-order moment space will be explained. Photon number measurements and post-selection make a plethora of quantum state engineering operations feasible. Quantum state engineering using non-Gaussian operations provides powerful tool for continuous variable quantum information. Practical challenges in their implementation and feasibility of generation of such states will be discussed [3,4]. Twin beams are generated in the same nonlinear process under stronger pumping, which are endowed with ideally perfect photon number correlations in the constituting signal and idler beams. This quantum feature is revealed by the sub-shot noise photon number correlations. However, the marginal signal and idler photon number distributions are multimode thermal. We illustrate the generation of engineered multimode quantum states from twin beams by photon subtraction and addition with supporting experimental realization. Future prospects, in view of our results, will be discussed. [1] K. Thapliyal and J. Peřina Jr., Ideal pairing of the Stokes and anti-Stokes photons in the Raman process, Phys. Rev. A 103, 033708 (2021). [2] K. Thapliyal, J. Peřina Jr., G. Chimczak, A. Kowalewska-Kudlaszyk, A. Miranowicz, Multiple quantum exceptional, diabolical, and hybrid points in multimode bosonic systems: I. Inherited and genuine singularities, arXiv:2405.01666 Communicated to Quantum (2024). [3] K. Thapliyal, J. Peřina Jr., O. Haderka, V. Michálek, and R. Machulka, Experimental characterization of multimode photon-subtracted twin beams, Phys. Rev. Res. 6, 013065 (2024). [4] J. Peřina Jr., K. Thapliyal, O. Haderka, V. Michálek, and R. Machulka, Generalized sub-Poissonian states of two-beam fields, Opt. Express 32, 537 (2024). Please find below the zoom link:- Join Zoom Meeting zoom.us/j/94529679427 Meeting ID: 945 2967 9427 Passcode: 661437 |
| * Announcement? | Institute |
| * Refreshments? | Before the event |
| * Honorarium? | None |
| Special Arrangements? | Digital Projection |
| * Host name and email | Sibasish Ghosh @@ sibasish@imsc.res.in |