arXiv subjects

Sandip Kumar Giri

Publications and source records attributed to Sandip Kumar Giri.

4 recordsLinked to original sources

arXiv2024

Higher-order nonclassicalities in hybrid coherent states

In the development of quantum technologies, nonclassical states have been playing a pivotal role, as quantum advantage cannot be obtained without appropriate utilization of nonclassicality. In the present work, we consider a hybrid coherent state (HCS), which is a coherent superposition of the single-photon-added coherent (SPAC) state and a coherent state (CS). Here, we report higher-order nonclassical properties of HCS with a specific focus on higher-order squeezing and higher-order antibunching. It's shown that HCS is experimentally realizable, and this engineered quantum state can be used to produce quantum states with desired higher-order nonclassical properties.

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arXiv2015

Higher order two-mode and multi-mode entanglement in Raman processes

The existence of higher order entanglement in the stimulated and spontaneous Raman processes is established using the perturbative solutions of the Heisenberg equations of motion for various field modes that are obtained using the Sen-Mandal technique and a fully quantum mechanical Hamiltonian that describes the stimulated and spontaneous Raman processes. Specifically, the perturbative Sen-Mandal solutions are exploited here to show the signature of the higher order two-mode and multi-mode entanglement. In some special cases, we have also observed higher order entanglement in the partially spontaneous Raman processes. Further, it is shown that the depth of the nonclassicality indicators (parameters) can be manipulated by the specific choice of coupling constants, and it is observed that the depth of nonclassicality parameters increases with the order.

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arXiv2014

Higher-order nonclassical properties of atom-molecule Bose-Einstein Condensate

The transient quantum statistical properties of the atoms and molecules in an atom-molecule BEC system are investigated by obtaining a third-order perturbative solution of the Heisenberg's equations of motion corresponding to the Hamiltonian of an atom-molecule BEC system where two atoms can collide to form a molecule. Time dependent quantities like two boson correlation, entanglement, squeezing, antibunching, etc., are computed and their properties are compared. It is established that atom-molecule BEC system is highly nonclassical as lower-order and higher-order squeezing and antibunching in pure (atomic and molecular) modes, squeezing and antibunching in compound mode and lower-order and higher-order entanglement in compound mode can be observed in the atom-molecule BEC system. Exact numerical results are also reported and analytic results obtained using the perturbative technique are shown to coincide with the exact numerical results.

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arXiv2013

Intermodal entanglement in Raman processes

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 $α_{1}$ 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.

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