Selective quantum state tomography for continuous-variable systems

TL;DR

This paper introduces a protocol for estimating specific elements of continuous-variable quantum states' density matrices efficiently, avoiding full state reconstruction, using adaptive discretization and controlled operations.

Contribution

It presents a novel adaptive measurement protocol for targeted quantum state tomography in continuous-variable systems, reducing complexity compared to full tomography.

Findings

Protocol successfully estimates density matrix elements

Numerical simulations demonstrate effectiveness

Method enables full state tomography with fewer measurements

Abstract

We present a protocol that allows the estimation of any density matrix element for continuous-variable quantum states, without resorting to the complete reconstruction of the full density matrix. The algorithm adaptatively discretizes the state and then, by resorting to controlled squeezing and translation operations, which are the main requirements for this algorithm, measures the density matrix element value. Furthermore, we show how this method can be used to achieve full quantum state tomography for continuous-variable quantum systems, alongside numerical simulations.