Quantum state reconstruction using binary data from on/off photodetection

TL;DR

This paper reviews the development of a quantum state reconstruction method that uses simple on/off photodetectors to determine the density matrix of quantum states, including both theoretical and experimental advances.

Contribution

It provides a comprehensive overview of the on/off detection method for quantum state reconstruction, extending its application from diagonal elements to the entire density matrix.

Findings

Successful reconstruction of diagonal density matrix elements using on/off detectors

Extension of the method to full density matrix reconstruction

Experimental validation of the theoretical approach

Abstract

The knowledge of the density matrix of a quantum state plays a fundamental role in several fields ranging from quantum information processing to experiments on foundations of quantum mechanics and quantum optics. Recently, a method has been suggested and implemented in order to obtain the reconstruction of the diagonal elements of the density matrix exploiting the information achievable with realistic on/off detectors, e.g. silicon avalanche photo-diodes, only able to discriminate the presence or the absence of light. The purpose of this paper is to provide an overview of the theoretical and experimental developments of the on/off method, including its extension to the reconstruction of the whole density matrix.