Nonlocality in Remote State Preparation vis-a-vis Teleportation

TL;DR

This paper investigates the nonlocality of quantum correlations in remote state preparation (RSP) and compares it with teleportation, revealing that the nonlocality involved is essentially the same for both protocols when using non-maximally entangled states.

Contribution

It introduces a unified nonlocality argument applicable to both teleportation and RSP, showing their nonlocal correlations are quantitatively equivalent under certain conditions.

Findings

Quantum violations of Bell-CHSH inequalities are equal for RSP and teleportation.

Maximum extractable nonlocality is the same for both protocols with non-maximally entangled states.

Differences between teleportation and RSP lie in classical communication, not nonlocality.

Abstract

The hitherto unexplored nonlocality of quantum correlations in the information transfer protocol of remote state preparation (RSP) is investigated in terms of a unified nonlocality argument formulated for teleportation as well as for two distinct RSP schemes. The argument differs only in the respective types of local measurements used in each scenario. One of the RSP schemes uses single particle projective measurements, while the other uses joint Bell-basis measurements. Interestingly, the quantum mechanical violations of the Bell-CHSH type inequalities formulated for each of the RSP setups, while being equal to each other, also turn out to be equal to that of the corresponding Bell-CHSH type local realist inequality for teleportation, using the common resource of non-maximally entangled state. This reveals that for such a resource state, the maximum amount of extractable nonlocality of correlations involved in the transfer of information is the same for the standard teleportation protocol and the two RSP schemes considered here, thereby implying that the essential difference between teleportation and remote state preparation lies in the amount of classical information required to be exchanged between parties, and not in the nonlocality of underlying correlations.