Signatures of nonclassical effects in optical tomograms

TL;DR

This paper demonstrates how various nonclassical effects in optical systems, including squeezing, revival phenomena, and entanglement, can be directly identified and quantified from optical tomograms without reconstructing the full quantum state.

Contribution

The authors introduce methods to detect and quantify nonclassical effects directly from optical tomograms, simplifying analysis of quantum states in single and bipartite systems.

Findings

Nonclassical effects like revival phenomena and squeezing can be obtained from tomograms.

Entanglement measures can be derived directly from tomograms, reflecting other entanglement quantifiers.

Procedures are adaptable to multimode quantum systems.

Abstract

Several nonclassical effects displayed by wave packets subject to generic nonlinear Hamiltonians can be identified and assessed directly from tomograms without attempting to reconstruct the Wigner function or the density matrix explicitly. We have demonstrated this for both single-mode and bipartite systems. We have shown that a wide spectrum of effects such as the revival phenomena, quadrature squeezing and Hong-Mandel and Hillery type higher-order squeezing in both the single-mode system and the double-well Bose-Einstein condensate can be obtained from appropriate tomograms in a straightforward manner. We have investigated entropic squeezing of the subsystem state of a bipartite system as it evolves in time, solely from tomograms. Further we have identified a quantifier of the extent of entanglement between subsystems which can be readily obtained from the tomogram and which mirrors the qualitative behavior of other measures of entanglement such as the subsystem von Neumann entropy and the subsystem linear entropy. The procedures that we have demonstrated can be readily adapted to multimode systems.