On the tomographic description of quantum systems: theory and applications

TL;DR

This paper develops a comprehensive quantum tomography theory extending classical signal detection methods to quantum systems, including algorithms and applications for reconstructing quantum states from measurable probability distributions.

Contribution

It introduces a novel quantum tomography framework, including a new numerical algorithm for group representation decomposition and applications to classical and quantum field systems.

Findings

Development of a quantum tomography theory based on classical detection methods

Introduction of the SMILY algorithm for group decomposition

Application of tomography to classical and quantum field systems

Abstract

In this job, we will present a theory called Quantum Tomography that is the natural extension of the theory of detection of signals in classical telecommunications to Quantum Mechanics. This theory mainly consists in the reconstruction of a quantum state of a system through a probability distribution measured directly in the laboratory, usually called Tomogram. This Thesis contains five chapters. In the first one, we will show the birth of this theory as an adaptation of homodyne and heterodyne classical detection to Quantum Mechanics. In the second, we will describe a tomographic description of Quantum Mechanics on C*-algebras by splitting the theory in two parts: a Generalized Sampling Theory and a Generalized Positive Transform. In the third, we will present the first numerical algorithm that solves the Clebsh-Gordan decomposition problem for any finite-dimensional unitary representation of any finite or compact Lie group. This algorithm receives the name of SMILY algorithm. In the fourth and fifth chapters, we will discuss tomography of systems parametrized with fields. In the fourth, we will reconstruct states of classical systems and in the fifth, we will do the same with quantum ones, but here in two different ways: the first one will be done by adapting the reconstruction formula of chapter four, and the second one by means of the axiomatic description of Wightamn-Streater of a Quantum Field Theory.