Browsing Fakultät für Physik (inkl. GAUSS) by Advisor "Kehrein, Stefan Prof. Dr."
Now showing items 1-10 of 10
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Eigenstate overlaps in the Transverse Field Ising Model and the Axial Next Nearest Neighbour Model
(2024-05-03)In this thesis, a possible extension of the adiabatic theorem for quantum quenches, i.e. non-adiabatic changes, is checked for its validity. In particular, the Transverse Field Ising Model (TFIM) and the related Axial Next ... -
Non-Equilibrium Dynamics of Photoexcited Correlated Quantum Matter
(2024-01-22)The interaction of time-dependent electromagnetic fields with electrons in quantum materials can give rise to many both fundamentally interesting as well as technologically relevant phenomena like transient band structure ... -
Analytic studies on the SYK models: from instantaneous thermalization to holographic duality
(2023-07-18)The quasiparticle picture is so prominent in condensed matter physics that it is almost taken as an axiom. Without this simplification, the physics becomes nearly intractable. However, the physics also becomes remarkable, ... -
Tripartite Information and Scrambling in Quantum Many-Body Systems
(2023-05-11)This thesis contributes to the study of quantum chaos and thermalization of closed quantum systems by applying tools from quantum information theory. We study scrambling – the delocalization of quantum information – in ... -
Microscopic foundation of the Eigenstate Thermalization Hypothesis
(2023-03-20)The Eigenstate Thermalization Hypothesis (ETH) explains how isolated quantum many-body systems thermalize by proposing that each energy eigenstate is already thermal. The hypothesis is believed to be essential to the ... -
Quantum quench dynamics in the transverse field Ising model of fully connected spins
(2021-04-06)The transverse field Ising model of N fully connected spins provides a mathematical accessible, yet non-trivial, system to investigate the non-thermal dynamics after a sudden quantum quench. The focus in this thesis is ... -
A Unitary Perturbation Theory Approach to Real-Time Evolution in the Hubbard Model
(2019-10-29)We advance perturbative approaches for out-of-equilibrium quantum many-body systems by applying unitary perturbation theory to the real-time evolution of the weakly interacting Hubbard model in d > 1 dimensions. We derive ... -
Dynamics of isolated quantum many-body systems far from equilibrium
(2018-01-22)This thesis addresses different aspects of the dynamics of isolated quantum many-body systems far from equilibrium, ranging from transient phenomena at short times to questions about relaxation and equilibration at late ... -
A Variational Cluster Approximation for the Heisenberg Model
(2017-04-13)In this thesis we present a novel variational cluster approximation for Heisenberg spin systems. It is based on the self-energy functional theory by Potthoff for fermionic and bosonic models with local interactions. To ... -
Thermalization in one-dimensional quantum-many-body systems
(2017-01-16)We consider the thermalization of the momentum distribution in two one-dimensional models. The first one is the integrable Hubbard model with an additional integrability breaking term in the Hamiltonian, which is a ...