Dynamical Correlations of Low Dimensional Quantum Magnets

Dynamical Correlations of Low Dimensional Quantum Magnets PDF Author: Andrew A. J. James
Publisher:
ISBN:
Category : Antiferromagnetism
Languages : en
Pages : 226

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Dynamical Correlations of Low Dimensional Quantum Magnets

Dynamical Correlations of Low Dimensional Quantum Magnets PDF Author: Andrew A. J. James
Publisher:
ISBN:
Category : Antiferromagnetism
Languages : en
Pages : 226

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Statics and Dynamics of Weakly Coupled Antiferromagnetic Spin-1/2 Ladders in a Magnetic Field

Statics and Dynamics of Weakly Coupled Antiferromagnetic Spin-1/2 Ladders in a Magnetic Field PDF Author: Pierre Bouillot
Publisher: Springer Science & Business Media
ISBN: 3642338089
Category : Computers
Languages : en
Pages : 104

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This thesis shows how a combination of analytic and numerical techniques, such as a time dependent and finite temperature Density Matrix Renormalization Group (DMRG) technique, can be used to obtain the physical properties of low dimensional quantum magnets with an unprecedented level of accuracy. A comparison between the theory and experiment then enables these systems to be used as quantum simulators; for example, to test various generic properties of low dimensional systems such as Luttinger liquid physics, the paradigm of one dimensional interacting quantum systems. Application of these techniques to a material made of weakly coupled ladders (BPCB) allowed the first quantitative test of Luttinger liquids. In addition, other physical quantities (magnetization, specific heat etc.), and more remarkably the spins-spin correlations – directly measurable in neutron scattering experiments – were in excellent agreement with the observed quantities. We thus now have tools to quantitatiively assess the dynamics for this class of quantum systems.

Finite-temperature Dynamics of Low-dimensional Quantum Systems with DMRG Methods

Finite-temperature Dynamics of Low-dimensional Quantum Systems with DMRG Methods PDF Author: Alexander Clemens Tiegel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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This thesis is concerned with the numerical study of one-dimensional (1D) spin-1/2 quantum magnets and related method development. Its focus is on the calculation of dynamical spin correlation functions both at zero and finite temperature. This is motivated by the accessibility of dynamical quantities in experiments such as inelastic neutron scattering (INS) and electron spin resonance (ESR). The numerical methods used in this thesis are based on extensions of the density-matrix renormalization group (DMRG) and are formulated in the framework of matrix product states (MPS). While zero-tempe...

Magnetic Field Effects in Low-Dimensional Quantum Magnets

Magnetic Field Effects in Low-Dimensional Quantum Magnets PDF Author: Adam Iaizzi
Publisher: Springer
ISBN: 3030018032
Category : Science
Languages : en
Pages : 170

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This thesis is a tour-de-force combination of analytic and computational results clarifying and resolving important questions about the nature of quantum phase transitions in one- and two-dimensional magnetic systems. The author presents a comprehensive study of a low-dimensional spin-half quantum antiferromagnet (the J-Q model) in the presence of a magnetic field in both one and two dimensions, demonstrating the causes of metamagnetism in such systems and providing direct evidence of fractionalized excitations near the deconfined quantum critical point. In addition to describing significant new research results, this thesis also provides the non-expert with a clear understanding of the nature and importance of computational physics and its role in condensed matter physics as well as the nature of phase transitions, both classical and quantum. It also contains an elegant and detailed but accessible summary of the methods used in the thesis—exact diagonalization, Monte Carlo, quantum Monte Carlo and the stochastic series expansion—that will serve as a valuable pedagogical introduction to students beginning in this field.

Dynamic Correlations in One-dimensional Quantum Magnets at Finite Temperature

Dynamic Correlations in One-dimensional Quantum Magnets at Finite Temperature PDF Author: Benedikt Fauseweh
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Tensor Network States and Effective Particles for Low-Dimensional Quantum Spin Systems

Tensor Network States and Effective Particles for Low-Dimensional Quantum Spin Systems PDF Author: Laurens Vanderstraeten
Publisher: Springer
ISBN: 3319641913
Category : Science
Languages : en
Pages : 229

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This thesis develops new techniques for simulating the low-energy behaviour of quantum spin systems in one and two dimensions. Combining these developments, it subsequently uses the formalism of tensor network states to derive an effective particle description for one- and two-dimensional spin systems that exhibit strong quantum correlations. These techniques arise from the combination of two themes in many-particle physics: (i) the concept of quasiparticles as the effective low-energy degrees of freedom in a condensed-matter system, and (ii) entanglement as the characteristic feature for describing quantum phases of matter. Whereas the former gave rise to the use of effective field theories for understanding many-particle systems, the latter led to the development of tensor network states as a description of the entanglement distribution in quantum low-energy states.

Characterizing Ground States of Low-dimensional Quantum Magnets

Characterizing Ground States of Low-dimensional Quantum Magnets PDF Author: Hyejin Ju
Publisher:
ISBN: 9781303052262
Category :
Languages : en
Pages : 196

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The study of frustration in quantum magnetism has been the focus of extensive research in the past couple of decades. The class of materials in this category is typically strongly correlated, due to strong electron-electron repulsion. In one- and two-dimensions, quantum fluctuations dominate these systems, and often, semi-classical approximations become an oversimplification. This thesis is concerned with exploring exotic physics that can emerge in low-dimensional quantum magnets. First, we use a T = 0 projected Monte Carlo algorithm in the valence bond basis to study the entanglement scaling of two-dimensional (2d) gapless systems. In particular, we focus on the resonating-valence-bond wavefunction as well as the gapless Goldstone mode in the Heisenberg model on the square lattice. We find that, in addition to the area law, there is a subleading, shape-dependent piece to the entanglement entropy, which is reminiscent of one dimensional (1d) gapless systems. We then explore the Heisenberg model under an applied magnetic field on the quasi-1d problem of a three-leg triangular spin tube (TST), using extensive density-matrix-renormalization group calculations coupled with analytical arguments to describe the results. We find that the physics describing this model differs from some of the well-known results on the two dimensional lattice, especially near low magnetic fields and at 1/3 magnetization. Finally, further research and possibilities in numerical techniques are discussed.

Charge Dynamics in Low Dimensional Prototype Correlated Systems : a View with High-energy X-rays

Charge Dynamics in Low Dimensional Prototype Correlated Systems : a View with High-energy X-rays PDF Author: Md-Zahid Hasan
Publisher:
ISBN:
Category : Particles (Nuclear physics)
Languages : en
Pages : 282

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Effective Models for Low-Dimensional Strongly Correlated Systems

Effective Models for Low-Dimensional Strongly Correlated Systems PDF Author: Ghassan George Batrouni
Publisher: Springer Science & Business Media
ISBN: 9780735403093
Category : Science
Languages : en
Pages : 340

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Book Description
These proceedings cover the most recent developments in the fields of high temperature superconductivity, magnetic materials and cold atoms in traps. Special emphasis is given to recently developed numerical and analytical methods, such as effective model Hamiltonians, density matrix renormalization group as well as quantum Monte Carlo simulations. Several of the contributions are written by the pioneers of these methods.

Magnetic Correlations in the One-dimensional Quantum Magnets Sr0.73CuO2 and Ca0.83CuO2 and the Mott-Hubbard System LaTiO3

Magnetic Correlations in the One-dimensional Quantum Magnets Sr0.73CuO2 and Ca0.83CuO2 and the Mott-Hubbard System LaTiO3 PDF Author: Gerhard Ingmar Meijer
Publisher:
ISBN: 9789036711012
Category :
Languages : en
Pages : 106

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