Pulsed homodyne Gaussian quantum tomography with low detection efficiency

TL;DR

This paper demonstrates that Gaussian quantum states can be accurately reconstructed using pulsed homodyne tomography even with detection efficiencies below 50%, expanding the method's practical applicability.

Contribution

It introduces the use of minimax adaptive reconstruction for Gaussian states in low-efficiency pulsed homodyne detection, showing effective state discrimination.

Findings

Successful numerical and experimental state reconstruction at <50% efficiency

Effective discrimination of Gaussian quantum states achieved

Method broadens applicability of quantum tomography in practical settings

Abstract

Pulsed homodyne quantum tomography usually requires a high detection efficiency limiting its applicability in quantum optics. Here, it is shown that the presence of low detection efficiency ($<50\%$) does not prevent the tomographic reconstruction of quantum states of light, specifically, of Gaussian type. This result is obtained by applying the so-called "minimax" adaptive reconstruction of the Wigner function to pulsed homodyne detection. In particular, we prove, by both numerical and real experiments, that an effective discrimination of different Gaussian quantum states can be achieved. Our finding paves the way to a more extensive use of quantum tomographic methods, even in physical situations in which high detection efficiency is unattainable.