Sommaire:

This thesis deals with energy management in open quantum systems. Three different systems are under study in the limit of weak system–environment coupling, and their dynamics is described by Markovian quantum master equations. In the first part of the talk, the derivation of such equation is briefly discussed in a specific case, and several notions of quantum thermodynamics are introduced. In the second part, a quantum system embedded in an out-of-thermal-equilibrium electromagnetic field is investigated. It is composed of a three-level atom playing the role of an absorption quantum thermal machine, as well as N two-level atoms (‘qubits’), with N = 1, . . . , 6, which are the target bodies. It is demonstrated that the machine is able to perform significant thermal tasks on the qubits, even when their number is increased. Moreover, it is pointed out that due to qubit–qubit interactions, the tasks delivered by the machine are distributed throughout the system of interacting qubits, such that in some cases the temperature of the qubits which are completely decoupled from the machine can still be considerably affected by it. This task-distribution mechanism is investigated by means of the correlations between different subparts of the system. In addition, the tuning of thermal tasks is discussed. In the third part, energy transport is investigated along atomic chains (between 2 and 7 atoms) embedded in blackbody radiation around room temperature. It is shown that the transport efficiency can reach remarkable values, exceeding 100% and reaching 1400% in some configurations. Moreover, when the efficiency is amplified, the transport range is also considerably increased. Finally, the fourth part also deals with energy transport in atomic chains. The quantum system is located at the interface of a photonic topological insulator (PTI), supporting a unidirectional surface-plasmon-polariton (SPP) immune to backscattering. The SPP propagates along the chain and assists energy transport. Comparison is made between reciprocal and unidirectional SPPs in terms of transport efficiency, and it is shown that the latter can yield an efficiency larger by one order of magnitude. In addition, several practical aspects stemming from PTIs are highlighted, including the robustness of
energy transport in the presence of defects on the SPP path.

Thesis committee:
Mário G. SILVEIRINHA, Professeur associé, Université de Lisboa (Rapporteur)
Guido PUPILLO, Professeur, Université de Strasbourg (Rapporteur)
Angela VASANELLI, Professeur, Université Paris-Diderot (Examinatrice)
David DEAN, Professeur, Université de Bordeaux (Examinateur)
Mauro ANTEZZA, Maître de conférence, Université de Montpellier (Directeur de thèse)
Riccardo MESSINA, Chargé de recherche, Université de Montpellier (Co-encadrant)

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