Applications of semi-definite optimization in quantum information protocols

TL;DR

This paper explores the use of semi-definite programming (SDP) in quantum information protocols, introducing new protocols and a numerical tool, with applications in quantum cryptography, randomness, and key distribution.

Contribution

It presents novel quantum information protocols based on SDP, including a new quantum key distribution method and tools for protocol analysis.

Findings

Developed a new quantum key distribution protocol based on Hardy’s paradox

Created several protocols for quantum random number expansion

Implemented a numerical tool for SDP-based quantum protocol analysis

Abstract

This work is concerned with the issue of applications of the semi-definite programming (SDP) in the field of quantum information science. Our results of the analysis of certain quantum information protocols using this optimization technique are presented, and an implementation of a relevant numerical tool is introduced. The key method used is NPA discovered by Navascues et al. [Phys. Rev. Lett. 98, 010401 (2007)]. In chapter 1 a brief overview of mathematical methods used in this work is presented. In chapter 2 an introduction to quantum information science is given. Chapter 3 concerns the device-independent (DI) and semi-device-independent (SDI) approaches in quantum cryptography. In chapter 4 our results regarding quantum information protocols which we developed using SDP are described. The results include a new type of quantum key distribution protocol based on Hardy's paradox; several protocols for quantum random number expansion; a method of formulation of SDP relaxations of SDI protocols; and a DI Santha-Vazirani source of randomness amplification protocol. In chapter 5 an introduction to interior point methods is given. In chapter 6 the implementation of our numerical tool dedicated to problems occurring in chapter 4 are discussed and compared with other solutions.