Multipartite maximally entangled states in symmetric scenarios

TL;DR

This paper introduces a class of symmetric multipartite states that are maximally entangled and can be transformed into any other state via LOCC, with applications to quantum cryptography and cloning.

Contribution

It identifies a maximally entangled state in symmetric scenarios and provides an efficient protocol for its construction and transformation, advancing quantum information processing.

Findings

Existence of a maximally entangled state in symmetric multipartite systems

Efficient protocols for state construction and transformation via LOCC

Application to symmetric quantum cloning and cryptography

Abstract

We consider the class of (N+1)-partite states suitable for protocols where there is a powerful party, the authority, and the other N parties play the same role, namely the state of their system live in the symmetric Hilbert space. We show that, within this scenario, there is a "maximally entangled state" that can be transform by a LOCC protocol into any other state. In addition, we show how to make the protocol efficiently including the construction of the state and discuss security issues for possible applications to cryptographic protocols. As an immediate consequence we recover a sequential protocol that implements the one to N symmetric cloning.