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Showing 1 to 18 of 18 for “"DMRG"”.
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Time-dependent properties of one-dimensional spin-systems : a DMRG-study
In this thesis we have applied the DMRG method to calculate dynamical and time-dependent properties of one-dimensional spin systems. Two different kinds of DMRG algorithms have been applied, and improved or generalized. In the correction vector DMRG used to calculate dynamical structure factors, …
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Density Matrix Renormalization Group Studies of Strongly Correlated Systems in Low Dimensions
The density matrix renormalization group method (DMRG) is a powerful numerical method for strongly correlated systems, which often cannot be solved analytically either by the mean field approach or through perturbation. The DMRG is originally proposed as an iterative search of the ground state in …
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Applications of the density matrix renormalization group to mesoscopic phenomena
… use the density-matrix renormalization group (DMRG), a numerical method that has been developed specifically for analyzing such systems. The following systems are discussed: - Josephson effect between superconducting nanograins: I investigate the Josephson effect, i.e. the dependence of the …
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Entanglement entropy in quantum many particle systems and their simulation via ansatz states
… the density-matrix renormalization-group (DMRG) is such a very successful method. The physical states of interest are approximated within a certain class of ansatz states. These ansatz states are designed in a way that the number of degrees of freedom are prevented from growing …
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Implementing a Lattice Formulation of the Schwinger Modelwith Periodic Boundary Conditions Using Tensor Networks
… in the density matrix renormalization group (DMRG) algorithm for finding the ground state of a quantum system. However, due to practical constraints, I still use matrix product states and matrix product operators with open boundary conditions. I demonstrate the efficacy of the model in …
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The adaptive time-dependent density matrix renormalization group method : development and applications
… density-matrix renormalization-group (adaptive t-DMRG), which turns out to be very well suited to investigate time-dependent phenomena in one-dimensional strongly correlated systems. The method is based on the original density-matrix renormalization group method by White and the time evolving …
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Grundzustandseigenschaften von anisotropen antiferromagnetischen Heisenberg-Ketten mit Spin S = 1
… is the density matrix renormalization group (DMRG) for a finite chain length and in the thermodynamic limit (iDMRG). The phase diagrams of the quantum spin chain and the corresponding classical model are compared for the first time. Thereby the similarity of the phase diagrams, the …
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Advances And Applications Of Static And Dynamic Correlation Methods In Ab-Initio Quantum Chemistry
… the first part, we discuss the orbital optimized DMRG method developed to treat static correlation in large strongly correlated systems. In the next part we discuss the two methods that can treat dynamic correlation in such complicated systems.
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Dynamics of quantum many-body systems with long-range interactions
… via the Density Matrix Renormalization Group (DMRG) methods in the context of the MPS and Matrix Product Operator(MPO) formalism. Further developing and optimizing these methods made it possible to obtain eigenstates and thermal states as well as to calculate the time dependent dynamics in …
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Ferrimagnetos quase-unidimensionais frustrados
… do Grupo de Renormalização da Matriz Densidade (DMRG, do inglês Density Matrix Renormalization Group). A cadeia AB2 (J =0) exibe estado fundamental ferrimagnético com magnetização m= 1 2 por célula unitária, como previsto pelo teorema de Lieb-Mattis. Para J=0, a fase ferrimagnética persiste até …
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Aspects of critical spin 1 chains and 2 dimensional symmetry protected topological phases of matter
… and the density matrix renormalization group (DMRG) algorithm. In particular, the bosonization method gives a formula for the evolution of four Tomonaga-Luttinger liquid (TLL) parameters as a function of the lattice parameters. Using the analytic formulae for the scaling dimensions in terms of …
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Numerical methods of characterizing symmetry protected topological states in one dimension
… on the density matrix renormalization group (DMRG) methods and explore the machine learning methods. We investigated different SPT phases in the context of interactions and disorders. The application of machine learning methods reveals new insights into the topological phases. We begin by …
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Dihedral non-Abelian Lattice Gauge Theories: Physics and Quantum Simulation
… of static charges through tensor-network DMRG simulations in the rishon formalism. We show that for odd $N$ static charges are screened by gluelumps---charge-glueball bound states enabled by the trivial centre of the group---while for even $N$ a fundamental flux string persists. Turning to …
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Simulating quantum systems on classical computers with matrix product states
… of the density-matrix renormalization group (DMRG). Based upon this connection, deeper understanding of the density matrix renormalization group can be obtained. After a general introduction in the first chapter of this thesis, the second chapter deals with Matrix-Product-States, focusing on …
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On the Phase Diagram of the Heisenberg Gamma Ladder
… Infinite Density Matrix Renormalization Group (iDMRG) numerical technique. In order to classify the phases, we search for discontinuities in the entanglement spectrum for bonds along one of the legs and the rungs of the ladder while also looking at divergences in the susceptibility of the energy. …
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Tensor network approaches to open quantum systems, higher dimensional lattices and random quantum circuits
This Dissertation was approved for publication on 2024-08-27 at 15:07.