The goal of research in quantum information is to investigate how quantum systems can be used to store, transmit and elaborate information and how the non-classical nature of their correlations allows defining protocols that outperform their classical counterparts. Despite of the many progresses, both theoretical and experimental, made in this field in the latest decades, many challenges lie ahead for practical implementations of quantum technologies. One of the most important ones is caused by the unavoidable interaction of quantum systems with their surroundings: The coupling to the environment is generally detrimental to the quantum information contained in the system as the system undergoes decoherence. In the quest for quantum technologies, it is fundamental to overcome the problem of decoherence and loss of information. Different physical implementations of qubits, such as superconducting and solid-state devices, are affected by the interaction with the environment in a way that can be described in terms of classical stochastic noise. The classical noise model can also be used to give an approximate, sometimes equivalent, description of full quantum models of system-environment interaction. This thesis contains my personal contribution to the study of the dynamics of discrete-variable quantum systems affected by classical noise. It covers in particular single- and two-qubit systems affected by Gaussian and non-Gaussian noise. It also discusses the dynamics of a quantum walk affected by spatially correlated classical noise. Analytical solutions for particular forms of noise and interactions, and a general numerical method for simulation of the dynamics are presented. Moreover, the thesis presents the experimental implementation of a quantum optical simulator of noisy dynamics of single-qubit systems. Finally, the use of quantum systems as probes of the spectral properties of large classical environments is discussed, showing that entanglement is a resource for improvements in the precision of the estimation.
DYNAMICS AND CHARACTERIZATION OF QUANTUM SYSTEMS INTERACTING WITH CLASSICAL NOISE / M. Rossi ; relatore: M. G. A. Paris ; correlatore: B. Vacchini ; coordinatore: F. Ragusa. - Milano : Università degli studi di Milano. DIPARTIMENTO DI FISICA, 2017 Nov 07. ((30. ciclo, Anno Accademico 2017.
|Titolo:||DYNAMICS AND CHARACTERIZATION OF QUANTUM SYSTEMS INTERACTING WITH CLASSICAL NOISE|
|Supervisori e coordinatori interni:||RAGUSA, FRANCESCO|
|Data di pubblicazione:||7-nov-2017|
|Settore Scientifico Disciplinare:||Settore FIS/03 - Fisica della Materia|
|Citazione:||DYNAMICS AND CHARACTERIZATION OF QUANTUM SYSTEMS INTERACTING WITH CLASSICAL NOISE / M. Rossi ; relatore: M. G. A. Paris ; correlatore: B. Vacchini ; coordinatore: F. Ragusa. - Milano : Università degli studi di Milano. DIPARTIMENTO DI FISICA, 2017 Nov 07. ((30. ciclo, Anno Accademico 2017.|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.13130/rossi-matteo_phd2017-11-07|
|Appare nelle tipologie:||Tesi di dottorato|