An investigation of nonclassical properties of light using an optical tomogram

TL;DR

This paper demonstrates how optical tomograms can directly reveal nonclassical properties, macroscopic superpositions, fractional revivals, and entanglement in light states, including effects of decoherence, without needing full state reconstruction.

Contribution

It introduces a method to visualize nonclassical features and entanglement directly from optical tomograms, simplifying analysis of complex quantum states of light.

Findings

Optical tomograms display signatures of macroscopic superpositions.

Fractional revivals produce sinusoidal structures in tomograms.

Entanglement signatures are observable directly in single-mode tomograms.

Abstract

By analyzing the optical tomogram of a linear superposition of coherent states, we show that distinctive signatures of the macroscopic superposition states are displayed directly in the optical tomograms of the states. We also study the effect of decoherence on the optical tomograms of the macroscopic superposition states. Since the wave packet fractional revivals are associated with the generation of macroscopic superposition states, these signatures help in visualizing the revivals and fractional revivals occurring in a nonlinear medium directly in the optical tomogram of the time-evolved state. We found that the optical tomogram of the time-evolved state at the instants of fractional revivals show structures with sinusoidal strands. Using a class of initial superposed wave packets evolving in the Kerr-like medium, we further show that the condition for the occurrence of fractional revival phenomenon depends on the number of wave packets composing the initial superposition state. In the case of a two-mode electromagnetic field, we investigate the entanglement of the state directly using the optical tomogram. We have shown that the signatures of entanglement can be observed directly in the single-mode optical tomogram of the state without reconstructing the density matrix of the system. We also analyze the effect of decoherence on the optical tomograms of the entangled states. Further, we examine the optical tomograms of the entangled states generated using a beam splitter with a Kerr medium placed into one of its input modes. We have found the signatures of entanglement in the optical tomogram for the entangled states generated at the instants of two- and three-subpacket fractional revival times.