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

Tensor Network States and Effective Particles for Low-Dimensional Quantum Spin Systems
Author: Laurens Vanderstraeten
Publisher: Springer
Total Pages: 229
Release: 2017-08-10
Genre: Science
ISBN: 3319641913

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.

Correlations in Low-Dimensional Quantum Gases

Correlations in Low-Dimensional Quantum Gases
Author: Guillaume Lang
Publisher: Springer
Total Pages: 193
Release: 2018-12-29
Genre: Science
ISBN: 3030052850

The book addresses several aspects of thermodynamics and correlations in the strongly-interacting regime of one-dimensional bosons, a topic at the forefront of current theoretical and experimental studies. Strongly correlated systems of one-dimensional bosons have a long history of theoretical study. Their experimental realisation in ultracold atom experiments is the subject of current research, which took off in the early 2000s. Yet these experiments raise new theoretical questions, just begging to be answered. Correlation functions are readily available for experimental measurements. In this book, they are tackled by means of sophisticated theoretical methods developed in condensed matter physics and mathematical physics, such as bosonization, the Bethe Ansatz and conformal field theory. Readers are introduced to these techniques, which are subsequently used to investigate many-body static and dynamical correlation functions.

Modern Theories of Many-Particle Systems in Condensed Matter Physics

Modern Theories of Many-Particle Systems in Condensed Matter Physics
Author: Daniel C. Cabra
Publisher: Springer Science & Business Media
Total Pages: 380
Release: 2012-01-05
Genre: Technology & Engineering
ISBN: 3642104487

Condensed matter systems where interactions are strong are inherently difficult to analyze theoretically. The situation is particularly interesting in low-dimensional systems, where quantum fluctuations play a crucial role. Here, the development of non-perturbative methods and the study of integrable field theory have facilitated the understanding of the behavior of many quasi one- and two-dimensional strongly correlated systems. In view of the same rapid development that has taken place for both experimental and numerical techniques, as well as the emergence of novel testing-grounds such as cold atoms or graphene, the current understanding of strongly correlated condensed matter systems differs quite considerably from standard textbook presentations. The present volume of lecture notes aims to fill this gap in the literature by providing a collection of authoritative tutorial reviews, covering such topics as quantum phase transitions of antiferromagnets and cuprate-based high-temperature superconductors, electronic liquid crystal phases, graphene physics, dynamical mean field theory applied to strongly correlated systems, transport through quantum dots, quantum information perspectives on many-body physics, frustrated magnetism, statistical mechanics of classical and quantum computational complexity, and integrable methods in statistical field theory. As both graduate-level text and authoritative reference on this topic, this book will benefit newcomers and more experienced researchers in this field alike.

Strongly Correlated Fermions and Bosons in Low-Dimensional Disordered Systems

Strongly Correlated Fermions and Bosons in Low-Dimensional Disordered Systems
Author: Igor V. Lerner
Publisher: Springer Science & Business Media
Total Pages: 405
Release: 2012-12-06
Genre: Science
ISBN: 9401005303

The physics of strongly correlated fermions and bosons in a disordered envi ronment and confined geometries is at the focus of intense experimental and theoretical research efforts. Advances in material technology and in low temper ature techniques during the last few years led to the discoveries of new physical of atomic gases and a possible metal phenomena including Bose condensation insulator transition in two-dimensional high mobility electron structures. Situ ations were the electronic system is so dominated by interactions that the old concepts of a Fermi liquid do not necessarily make a good starting point are now routinely achieved. This is particularly true in the theory of low dimensional systems such as carbon nanotubes, or in two dimensional electron gases in high mobility devices where the electrons can form a variety of new structures. In many of these sys tems disorder is an unavoidable complication and lead to a host of rich physical phenomena. This has pushed the forefront of fundamental research in condensed matter towards the edge where the interplay between many-body correlations and quantum interference enhanced by disorder has become the key to the understand ing of novel phenomena.

Correlation Effects in Low-Dimensional Electron Systems

Correlation Effects in Low-Dimensional Electron Systems
Author: Ayao Okiji
Publisher: Springer Science & Business Media
Total Pages: 223
Release: 2012-12-06
Genre: Science
ISBN: 3642851290

Correlation Effects in Low-Dimensional Electron Systems describes recent developments in theoretical condensed-matter physics, emphasizing exact solutions in one dimension including conformal-field theoretical approaches, the application of quantum groups, and numerical diagonalization techniques. Various key properties are presented for two-dimensional, highly correlated electron systems.

Correlation Effects in Low-dimensional Electron Systems

Correlation Effects in Low-dimensional Electron Systems
Author: Ayao Okiji
Publisher: Springer
Total Pages: 240
Release: 1994
Genre: Science
ISBN:

Correlation Effects in Low-Dimensional Electron Systems describes recent developments in theoretical condensed-matter physics, emphasizing exact solutions in one dimension including conformal-field theoretical approaches, the application of quantum groups, and numerical diagonalization techniques. Various key properties are presented for two-dimensional, highly correlated electron systems.

Quantum Many-particle Systems

Quantum Many-particle Systems
Author: John W. Negele
Publisher: CRC Press
Total Pages: 361
Release: 2018-03-05
Genre: Science
ISBN: 0429977557

This book explains the fundamental concepts and theoretical techniques used to understand the properties of quantum systems having large numbers of degrees of freedom. A number of complimentary approaches are developed, including perturbation theory; nonperturbative approximations based on functional integrals; general arguments based on order parameters, symmetry, and Fermi liquid theory; and stochastic methods.

Quantum Correlations in Field Theory and Integrable Systems

Quantum Correlations in Field Theory and Integrable Systems
Author: Stefano Evangelisti
Publisher: Minkowski Institute Press
Total Pages: 213
Release: 2013-05-31
Genre: Science
ISBN: 1927763096

This doctoral thesis analytically and numerically examines some of the most important concepts in quantum correlations in low-dimensional physics: entanglement and out-of-equilibrium dynamics. As John Bell once said: "Entanglement expresses the spooky nonlocality inherent to quantum mechanics", and its study not only concerns the foundations of any quantum theory, but also has important applications in quantum information and condensed matter theory, amongst others. The first chapters are devoted to the study of "entanglement entropies", a popular measure of the "quantumness" of a physical system. The main focus of the analysis is the one-dimensional XYZ spin-1/2 chain in equilibrium, an interacting theory which in addition to being integrable also has interesting scaling limits, such as the sine-Gordon field theory. Moving away from equilibrium the subsequent chapters deal with the dynamics of quantum correlators after an instantaneous quantum quench. The emphasis is on two different models and techniques; the transverse field Ising chain is studied using the form-factor approach and the O(3) non-linear sigma model is studied by means of the semi-classical theory. In the final chapter the author highlights an important general result: in the absence of long-range interactions in the final Hamiltonian the dynamics of a quantum system are determined by the same statistical ensemble that describes static correlations.

Effective Models for Low-Dimensional Strongly Correlated Systems

Effective Models for Low-Dimensional Strongly Correlated Systems
Author: Ghassan George Batrouni
Publisher: Springer Science & Business Media
Total Pages: 340
Release: 2006-02-23
Genre: Science
ISBN: 9780735403093

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.