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A Tale of Two Times: Simulating Time-Resolved Spectral Properties With the Two-Time Non-Equilibrium Green's Function
A Tale of Two Times: Simulating Time-Resolved Spectral Properties With the Two-Time Non-Equilibrium Green's Function
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202104832
- ISBN
- 9798297662742
- DDC
- 530
- 서명/저자
- A Tale of Two Times: Simulating Time-Resolved Spectral Properties With the Two-Time Non-Equilibrium Greens Function
- 발행사항
- [Sl] : University of California, Santa Barbara, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 321 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 87-04, Section: B.
- 주기사항
- Advisor: Vlcek, Vojtech;Ludwig, Andreas.
- 학위논문주기
- Thesis (Ph.D.)--University of California, Santa Barbara, 2025.
- 초록/해제
- 요약In this thesis we present developments in the simulation of non-equilibrium quantum systems using the non-equilibrium Green's function (NEGF) formalism. The work in this thesis is motivated by the growing interest in ultrafast phenomena and time-resolved experiments and by the lack of an efficient, accurate and systematically improvable approach for the simulation of these experiments from first principles. The many-body Green's function formalism, which has found great success in equilibrium, can readily be applied to non-equilibrium problems in theory, but in practice it suffers from scaling issues that make it prohibitively expensive in practical calculations. The research presented provides investigation into and solutions to shortcomings of existing NEGF propagation schemes. The main result of this thesis offers a route to overcoming the identified shortcomings in the context of simulating time-resolved photoemission spectroscopy, a key probe for ultrafast and non-equilibrium science. This new methodology, the real-time Dyson expansion (RT-DE), is based on the inclusion of dynamical many-body correlations as a correction to a non-correlated (mean-field), non-equilibrium spectral function. It is a practical and scalable approach that extends a well known and broadly applied equilibrium methodology to time-dependent problems. Further, to complement this new methodology we have investigated applying numerical approaches based on extrapolation and interpolation to further reduce cost of Green's function propagation. We apply the RT-DE to several problems, showing it's significant improvement over non-dynamically correlated methods. In particular, we investigate the problem of band-gap renormalization in photexcited, gapped systems and show the RT-DE is qualitatively consistent with experiment as well as providing a novel prediction of how band-gap renormalization properties can be tuned in insulating/semiconducting systems. Chapter 1 gives an introduction and motivation for the remainder of the thesis. Chapter 2 introduces the theoretical background relevant for the research work presented here. Chapter 3 gives an overview of the papers presented in chapters 4-9. In chapter 4 we perform a comprehensive benchmark of several wavefunction and Green's function based time-dependent methods. Chapter 5 investigates one of the most widely used approximations used in the field of NEGFs and provides concrete explanation behind it's typically excellent performance. Chapter 6 investigates the use of dynamical mode decomposition as a numerical technique to extrapolate dynamics of the NEGF. Chapter 7 introduces our new method (RT-DE), showing it's derivation and providing numerical demonstrations of its efficacy. Chapter 8 provides an application of the RT-DE to study the role of dynamical screening and carrier mobility in the band-gap renormalization of photexcited semiconductors. Chapter 9 provides a summary of the main results presented in this thesis and an outlook for future work on developing a framework for the efficient, first principles simulation of time-resolved spectra of quantum systems.
- 일반주제명
- Physics
- 일반주제명
- Applied mathematics
- 일반주제명
- Physical chemistry
- 일반주제명
- Materials science
- 일반주제명
- Optics
- 기타저자
- University of California, Santa Barbara Physics
- 기본자료저록
- Dissertations Abstracts International. 87-04B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520260202104832
■006m o d
■007cr#unu||||||||
■020 ▼a9798297662742
■035 ▼a(MiAaPQ)AAI32170783
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aReeves, Cian Charles.
■24512▼aA Tale of Two Times: Simulating Time-Resolved Spectral Properties With the Two-Time Non-Equilibrium Green's Function
■260 ▼a[Sl]▼bUniversity of California, Santa Barbara▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a321 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 87-04, Section: B.
■500 ▼aAdvisor: Vlcek, Vojtech;Ludwig, Andreas.
■5021 ▼aThesis (Ph.D.)--University of California, Santa Barbara, 2025.
■520 ▼aIn this thesis we present developments in the simulation of non-equilibrium quantum systems using the non-equilibrium Green's function (NEGF) formalism. The work in this thesis is motivated by the growing interest in ultrafast phenomena and time-resolved experiments and by the lack of an efficient, accurate and systematically improvable approach for the simulation of these experiments from first principles. The many-body Green's function formalism, which has found great success in equilibrium, can readily be applied to non-equilibrium problems in theory, but in practice it suffers from scaling issues that make it prohibitively expensive in practical calculations. The research presented provides investigation into and solutions to shortcomings of existing NEGF propagation schemes. The main result of this thesis offers a route to overcoming the identified shortcomings in the context of simulating time-resolved photoemission spectroscopy, a key probe for ultrafast and non-equilibrium science. This new methodology, the real-time Dyson expansion (RT-DE), is based on the inclusion of dynamical many-body correlations as a correction to a non-correlated (mean-field), non-equilibrium spectral function. It is a practical and scalable approach that extends a well known and broadly applied equilibrium methodology to time-dependent problems. Further, to complement this new methodology we have investigated applying numerical approaches based on extrapolation and interpolation to further reduce cost of Green's function propagation. We apply the RT-DE to several problems, showing it's significant improvement over non-dynamically correlated methods. In particular, we investigate the problem of band-gap renormalization in photexcited, gapped systems and show the RT-DE is qualitatively consistent with experiment as well as providing a novel prediction of how band-gap renormalization properties can be tuned in insulating/semiconducting systems. Chapter 1 gives an introduction and motivation for the remainder of the thesis. Chapter 2 introduces the theoretical background relevant for the research work presented here. Chapter 3 gives an overview of the papers presented in chapters 4-9. In chapter 4 we perform a comprehensive benchmark of several wavefunction and Green's function based time-dependent methods. Chapter 5 investigates one of the most widely used approximations used in the field of NEGFs and provides concrete explanation behind it's typically excellent performance. Chapter 6 investigates the use of dynamical mode decomposition as a numerical technique to extrapolate dynamics of the NEGF. Chapter 7 introduces our new method (RT-DE), showing it's derivation and providing numerical demonstrations of its efficacy. Chapter 8 provides an application of the RT-DE to study the role of dynamical screening and carrier mobility in the band-gap renormalization of photexcited semiconductors. Chapter 9 provides a summary of the main results presented in this thesis and an outlook for future work on developing a framework for the efficient, first principles simulation of time-resolved spectra of quantum systems.
■590 ▼aSchool code: 0035.
■650 4▼aPhysics
■650 4▼aApplied mathematics
■650 4▼aPhysical chemistry
■650 4▼aMaterials science
■650 4▼aOptics
■653 ▼aNon-equilibrium Green's function
■653 ▼aTime-resolved photoemission spectroscopy
■653 ▼aReal-time Dyson expansion
■653 ▼aPhotexcited semiconductors
■653 ▼aKadanoff-Baym equations
■690 ▼a0605
■690 ▼a0752
■690 ▼a0794
■690 ▼a0364
■690 ▼a0494
■71020▼aUniversity of California, Santa Barbara▼bPhysics.
■7730 ▼tDissertations Abstracts International▼g87-04B.
■790 ▼a0035
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17359085▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
