Reducing the entropic uncertainty lower bound in the presence of quantum memory via LOCC

¹ Department of Physics, Sanandaj Branch, Islamic Azad University - Sanandaj, Iran
² Department of Physics, Sharif University of Technology - P.O. Box 11155-9161, Tehran, Iran
³ Department of Physics, University of Kurdistan - P.O. Box 66177-15175, Sanandaj, Iran

^(a) shsalimi@uok.ac.ir

Received: 25 July 2016
Accepted: 2 October 2016

Abstract

The uncertainty principle sets a lower bound on the uncertainties of two incompatible observables measured on a particle. The uncertainty lower bound can be reduced by considering a particle as a quantum memory entangled with the measured particle. In this paper, we consider a tripartite scenario in which a quantum state has been shared among Alice, Bob, and Charlie. The aim of Bob and Charlie is to minimize Charlie's lower bound about Alice's measurement outcomes. To this aim, they concentrate their correlation with Alice in Charlie's side via a cooperative strategy based on local operations and classical communication. We obtain a lower bound for Charlie's uncertainty about Alice's measurement outcomes after concentrating information and compare it with the lower bound without concentrating information in some examples. We also provide a physical interpretation of the entropic uncertainty lower bound based on the dense coding capacity.