Sequential information theoretic protocols in continuous variable systems

TL;DR

This paper introduces two resource-efficient schemes for sequential quantum information protocols in continuous variable systems, enabling multiple observers to sequentially detect entanglement and perform teleportation with improved reusability.

Contribution

It proposes novel resource reusability schemes—resource-splitting and unsharp measurements—for sequential quantum protocols in continuous variables, enhancing protocol robustness.

Findings

Resource-splitting improves sequential teleportation success.

Unsharp measurements enable multiple observers to detect entanglement.

Up to five observers can sequentially witness entanglement.

Abstract

In order to enable the sequential implementation of quantum information theoretic protocols in the continuous variable framework, we propose two schemes for resource reusability, resource-splitting protocol and unsharp homodyne measurements. We demonstrate the advantage offered by the first scheme in implementing sequential attempts at continuous variable teleportation when the protocol fails in the previous round. In the second scheme, unsharp quadrature measurements are employed to implement the detection of entanglement between several pairs of observers. Under specific conditions, our calculations show that it is possible to successfully witness the entanglement of the same two-mode state, sequentially by as many as five observers.