Out-of-equilibrium thermodynamics and non-thermal heat engines

Detalhes bibliográficos
Autor(a) principal: Cherubim, Cleverson Francisco
Data de Publicação: 2020
Tipo de documento: Tese
Idioma: eng
Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
Texto Completo: https://www.teses.usp.br/teses/disponiveis/76/76131/tde-28092020-162459/
Resumo: Quantum thermodynamics (QT) is an emerging field of research that aims to investigate how the laws of thermodynamics and quantum mechanics merge together in small quantum systems. With advances at the necessary technology to control and measure those small physical systems this field has acquired even more importance, not only in the sense that it can be tested, which is a good thing for basic research, but that new applications could be implemented at these scales, so a better comprehension of the limitations imposed by quantum thermodynamics turns out to be of crucial importance for these goals, which forces theoreticians to produce experimentally relevant versions of these new concepts. Another important aspect present at those systems is that part of them work in a regime where its constituents are described by non-thermal states, and in particular non-thermal steady states, which brings to light a different thermodynamic description, usually called steady-state thermodynamics, therefore one of the goals that we are willing to achieve with this thesis is to give an introduction to QT of systems out-of-equilibrium. One of the related subtopics that physicists deal with in QT and the one that we will be focusing on this work are the use of non-thermal stationary states to build heat engines in the quantum domain, and the analyses of the features that this new regime could possibly allow, like the use of quantum resources as a way to overcome classical limitations imposed on its performance, like to attain efficiencies higher than Carnots or operate in certain regimes unattainable using only classical resources. Therefore, in order to clarify the underlying physics of those systems in a non-thermal regime, any experimentally well suited content is more than welcome. So keeping that in mind we devised an experimentally relevant thermodynamic cycle for a transmon qubit WS interacting with a non-thermal environment composed by two subsystems, an externally excited cavity and a classical heat bath with temperature T. The WS undergoes a non-conventional cycle (different from Otto, Carnot, etc.) through a succession of non-thermal stationary states obtained by slowly varying its bare frequency and the amplitude of the field applied on the cavity. The efficiency of this engine obtains a maximum value up to 47% in the regime of operation used. We also wanted to look for the role played by the different types of coherences, present at the WS, on the behavior of the engine and its efficiency. By different types of coherence we mean the so called modes of coherence, whose definition is based on how they respond to symmetry transformations. We did that for the trivial case of the qubit, that only contains the modes 1 and -1, and that has shown to be extremely important for the efficiency of the machine. The same procedure was repeated for a 3-level system WS. The modes 1 and -1 was again very important, not only to the absolute value of the engines efficiency but to the regime of operation of the machine. The additional modes, 2 and -2, had a negative impact on the efficiency, reducing its absolute value. This result appears to show some evidences that quantumness wont necessarily bring improvements to the operation of those machines.
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spelling Out-of-equilibrium thermodynamics and non-thermal heat enginesTermodinâmica fora do equilíbrio e máquinas não-térmicasMáquina térmica quânticaOut-of-equilibrium thermodynamicsQuantum heat engineQuantum ThermodynamicsSteady-state thermodynamicsTermodinâmica de estados estacionáriosTermodinâmica fora do equilíbrioTermodinâmica quânticaQuantum thermodynamics (QT) is an emerging field of research that aims to investigate how the laws of thermodynamics and quantum mechanics merge together in small quantum systems. With advances at the necessary technology to control and measure those small physical systems this field has acquired even more importance, not only in the sense that it can be tested, which is a good thing for basic research, but that new applications could be implemented at these scales, so a better comprehension of the limitations imposed by quantum thermodynamics turns out to be of crucial importance for these goals, which forces theoreticians to produce experimentally relevant versions of these new concepts. Another important aspect present at those systems is that part of them work in a regime where its constituents are described by non-thermal states, and in particular non-thermal steady states, which brings to light a different thermodynamic description, usually called steady-state thermodynamics, therefore one of the goals that we are willing to achieve with this thesis is to give an introduction to QT of systems out-of-equilibrium. One of the related subtopics that physicists deal with in QT and the one that we will be focusing on this work are the use of non-thermal stationary states to build heat engines in the quantum domain, and the analyses of the features that this new regime could possibly allow, like the use of quantum resources as a way to overcome classical limitations imposed on its performance, like to attain efficiencies higher than Carnots or operate in certain regimes unattainable using only classical resources. Therefore, in order to clarify the underlying physics of those systems in a non-thermal regime, any experimentally well suited content is more than welcome. So keeping that in mind we devised an experimentally relevant thermodynamic cycle for a transmon qubit WS interacting with a non-thermal environment composed by two subsystems, an externally excited cavity and a classical heat bath with temperature T. The WS undergoes a non-conventional cycle (different from Otto, Carnot, etc.) through a succession of non-thermal stationary states obtained by slowly varying its bare frequency and the amplitude of the field applied on the cavity. The efficiency of this engine obtains a maximum value up to 47% in the regime of operation used. We also wanted to look for the role played by the different types of coherences, present at the WS, on the behavior of the engine and its efficiency. By different types of coherence we mean the so called modes of coherence, whose definition is based on how they respond to symmetry transformations. We did that for the trivial case of the qubit, that only contains the modes 1 and -1, and that has shown to be extremely important for the efficiency of the machine. The same procedure was repeated for a 3-level system WS. The modes 1 and -1 was again very important, not only to the absolute value of the engines efficiency but to the regime of operation of the machine. The additional modes, 2 and -2, had a negative impact on the efficiency, reducing its absolute value. This result appears to show some evidences that quantumness wont necessarily bring improvements to the operation of those machines.Termodinâmica quântica (TQ) é um campo de pesquisa recente que visa investigar como as leis da termodinâmica e da mecânica quântica funcionam em conjunto em pequenos sistemas quânticos. Com avanços na tecnologia necessária para controlar e medir esses pequenos sistemas, esta área de pesquisa tem adquirido cada vez mais importância, não somente no sentido de que agora eles podem começar a serem testadas, o que é algo de extrema importância para pesquisa, mas também que novas aplicações podem ser implementadas nessas escalas, portanto, uma boa compreensão das limitações impostas pela termodinâmica quântica torna-se de suma importância na busca desses objetivos, o que força físicos teóricos a produzir conteúdos experimentalmente relevantes desses novos conceitos. Outro aspecto importante associado a estes sistemas é que parte deles pode operar fora do equilíbrio termodinâmico, sendo descritos por estados não térmicos, e em particular estados não térmicos estacionários, devendo portanto serem descritos termodinamicamente de maneira distinta, o que geralmente recebe o nome de termodinâmica de estados estacionários, portanto um dos principais objetivos desta tese será o de fornecer uma introdução a TQ de sistemas fora do equilíbrio. Um dos mais importantes subtópicos estudados em TQ e o que daremos bastante ênfase nesta tese será o uso de estados estacionários não térmicos na construção de máquinas operando no regime quântico, e a análise das novas características que este regime podem propiciar, como o uso de recursos quânticos com o intuito de superar limitações clássicas em sua performance, como a obtenção de eficiências superiores a eficiência de Carnot ou operar em certos regimes não permitidos usando somente ingredientes clássicos. Portanto, vemos que é de suma importância tornar mais clara a compreensão de sistemas operando fora do regime térmico e que qualquer conteúdo produzido que esteja bem adequado a verificações experimentais é muito mais que bemvindo. Elaboramos um ciclo termodinâmico relevante sob o ponto de vista experimental usando um transmon no regime de qubit como ST em contato com um ambiente não térmico composto por dois subsistemas, uma cavidade excitada por um campo externo e banho clássico com temperatura T. A ST passa por um ciclo não convencional (diferente dos ciclos de Otto, Carnot, etc.) através de uma sucessão de estados estcionários não térmicos obtidos através da variação muito lenta de sua frequência e da amplitude do campo externo aplicado à cavidade. A eficiência dessa máquina adquire um valor máximo da ordem de 47% no regime de operação usado. Também queríamos olhar para o papel dos diferentes tipos de coerência, presentes na ST, sobre o comportamento da máquina e sua eficiência. Por diferentes tipos de coerência nós nos referimos aos tão conhecidos modos de coerência, cuja definição se baseia em como elas respondem a transformações de simetria. Fizemos essa análise para o caso trivial do qubit, que contém somente os modos 1 e -1, e que se demonstraram ser de extrema importante para a eficiência da máquina. O mesmo procedimento foi repetido para um sistema de 3 níveis usado como ST. Os modos 1 e -1 se demonstraram novamente bastante importantes, não somente para o valor absoluto da máquina mas também para o regime de funcionamento desta. Os modos adicionais, 2 e -2, tiveram um impacto negativo na eficiência, reduzindo seu valor absoluto. Este resultado parece nos fornecer evidências de que \"quantumness\" não necessariamente trará ganhos à operação dessas máquinas.Biblioteca Digitais de Teses e Dissertações da USPBrito, Frederico Borges deCherubim, Cleverson Francisco2020-07-27info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/76/76131/tde-28092020-162459/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2020-10-21T21:34:43Zoai:teses.usp.br:tde-28092020-162459Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212020-10-21T21:34:43Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false
dc.title.none.fl_str_mv Out-of-equilibrium thermodynamics and non-thermal heat engines
Termodinâmica fora do equilíbrio e máquinas não-térmicas
title Out-of-equilibrium thermodynamics and non-thermal heat engines
spellingShingle Out-of-equilibrium thermodynamics and non-thermal heat engines
Cherubim, Cleverson Francisco
Máquina térmica quântica
Out-of-equilibrium thermodynamics
Quantum heat engine
Quantum Thermodynamics
Steady-state thermodynamics
Termodinâmica de estados estacionários
Termodinâmica fora do equilíbrio
Termodinâmica quântica
title_short Out-of-equilibrium thermodynamics and non-thermal heat engines
title_full Out-of-equilibrium thermodynamics and non-thermal heat engines
title_fullStr Out-of-equilibrium thermodynamics and non-thermal heat engines
title_full_unstemmed Out-of-equilibrium thermodynamics and non-thermal heat engines
title_sort Out-of-equilibrium thermodynamics and non-thermal heat engines
author Cherubim, Cleverson Francisco
author_facet Cherubim, Cleverson Francisco
author_role author
dc.contributor.none.fl_str_mv Brito, Frederico Borges de
dc.contributor.author.fl_str_mv Cherubim, Cleverson Francisco
dc.subject.por.fl_str_mv Máquina térmica quântica
Out-of-equilibrium thermodynamics
Quantum heat engine
Quantum Thermodynamics
Steady-state thermodynamics
Termodinâmica de estados estacionários
Termodinâmica fora do equilíbrio
Termodinâmica quântica
topic Máquina térmica quântica
Out-of-equilibrium thermodynamics
Quantum heat engine
Quantum Thermodynamics
Steady-state thermodynamics
Termodinâmica de estados estacionários
Termodinâmica fora do equilíbrio
Termodinâmica quântica
description Quantum thermodynamics (QT) is an emerging field of research that aims to investigate how the laws of thermodynamics and quantum mechanics merge together in small quantum systems. With advances at the necessary technology to control and measure those small physical systems this field has acquired even more importance, not only in the sense that it can be tested, which is a good thing for basic research, but that new applications could be implemented at these scales, so a better comprehension of the limitations imposed by quantum thermodynamics turns out to be of crucial importance for these goals, which forces theoreticians to produce experimentally relevant versions of these new concepts. Another important aspect present at those systems is that part of them work in a regime where its constituents are described by non-thermal states, and in particular non-thermal steady states, which brings to light a different thermodynamic description, usually called steady-state thermodynamics, therefore one of the goals that we are willing to achieve with this thesis is to give an introduction to QT of systems out-of-equilibrium. One of the related subtopics that physicists deal with in QT and the one that we will be focusing on this work are the use of non-thermal stationary states to build heat engines in the quantum domain, and the analyses of the features that this new regime could possibly allow, like the use of quantum resources as a way to overcome classical limitations imposed on its performance, like to attain efficiencies higher than Carnots or operate in certain regimes unattainable using only classical resources. Therefore, in order to clarify the underlying physics of those systems in a non-thermal regime, any experimentally well suited content is more than welcome. So keeping that in mind we devised an experimentally relevant thermodynamic cycle for a transmon qubit WS interacting with a non-thermal environment composed by two subsystems, an externally excited cavity and a classical heat bath with temperature T. The WS undergoes a non-conventional cycle (different from Otto, Carnot, etc.) through a succession of non-thermal stationary states obtained by slowly varying its bare frequency and the amplitude of the field applied on the cavity. The efficiency of this engine obtains a maximum value up to 47% in the regime of operation used. We also wanted to look for the role played by the different types of coherences, present at the WS, on the behavior of the engine and its efficiency. By different types of coherence we mean the so called modes of coherence, whose definition is based on how they respond to symmetry transformations. We did that for the trivial case of the qubit, that only contains the modes 1 and -1, and that has shown to be extremely important for the efficiency of the machine. The same procedure was repeated for a 3-level system WS. The modes 1 and -1 was again very important, not only to the absolute value of the engines efficiency but to the regime of operation of the machine. The additional modes, 2 and -2, had a negative impact on the efficiency, reducing its absolute value. This result appears to show some evidences that quantumness wont necessarily bring improvements to the operation of those machines.
publishDate 2020
dc.date.none.fl_str_mv 2020-07-27
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/doctoralThesis
format doctoralThesis
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dc.identifier.uri.fl_str_mv https://www.teses.usp.br/teses/disponiveis/76/76131/tde-28092020-162459/
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language eng
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dc.rights.driver.fl_str_mv Liberar o conteúdo para acesso público.
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Liberar o conteúdo para acesso público.
eu_rights_str_mv openAccess
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dc.publisher.none.fl_str_mv Biblioteca Digitais de Teses e Dissertações da USP
publisher.none.fl_str_mv Biblioteca Digitais de Teses e Dissertações da USP
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reponame:Biblioteca Digital de Teses e Dissertações da USP
instname:Universidade de São Paulo (USP)
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instname_str Universidade de São Paulo (USP)
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institution USP
reponame_str Biblioteca Digital de Teses e Dissertações da USP
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repository.name.fl_str_mv Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)
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