Measurement induced nonclassical states from coherent state heralded by Knill-Laflamme-Milburn-type SU(3) interference

TL;DR

This paper proposes a method to generate nonclassical, non-Gaussian states from coherent states using SU(3) interferometry and photon counting, enhancing nonclassical features like squeezing and negativity of the Wigner function.

Contribution

It introduces a novel scheme combining KLM-type SU(3) interference with heralded photon detection to produce highly nonclassical states from coherent inputs.

Findings

Achieved up to 1.9 dB squeezing in generated states

Demonstrated negativity in Wigner function indicating nonclassicality

Showed transformation of coherent states into non-Gaussian states with enhanced nonclassical features

Abstract

We theoretically generate nonclassical states from coherent state heralded by Knill-Laflamme-Milburn (KLM)-type SU(3) interference. Injecting a coherent state in signal mode and two single-photon sources in other two auxiliary modes of SU(3) interferometry, a broad class of useful nonclassical states are obtained in the output signal port after making two single-photon-counting measurements in the two output auxiliary modes. The nonclassical properties, in terms of anti-bunching effect and squeezing effect as well as the negativity of the Wigner function, are studied in detail by adjusting the interaction parameters. The results show that the input coherent state can be transformed into non-Gaussian states with higher nonclassicality after measurement induction. The maximum squeezing of our generated states can be arrived at about 1.9 dB.