Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

AIP conference proceedings

Quantum Magnetism, Nanomagnets and Entanglement

Stephan Haas, Adolfo Avella, Ferdinando Mancini

Published Jan 1, 2008• 1 citation
Publisher

Abstract

These lecture notes give an introduction to quantum magnetism. We start by a discussion of paramagnetism and the Weiss meanfield theory applied to the Ising model. In the following sections, we turn to the fully quantum‐mechanical Heisenberg Hamiltonian. First, we consider the limit of small clusters whose properties we analyze via exact diagonalization. Bulk quantum magnets are then within the framework of the linear spinwave theory. A short discussion of Monte Carlo techniques follows. Finally, we discuss aspects of entanglement in quantum spin systems.

DOI
10.1063/1.2940446

Related papers

1 Computational Studies of Quantum Spin Systems

Anders W. Sandvik

These lecture notes introduce quantum spin systems and several computational methods for studying their ground-state and finite-temperature properties. Symmetry-breaking and critical phenomena are first discussed in the simpler setting of Monte Carlo studies of classical spin systems, to illustrate finite-size scaling at continuous and first-order phase transitions. Exact diagonalization and quantum Monte Carlo (stochastic series expansion) algorithms and their computer implementations are then discussed in detail. Applications of the methods are illustrated by results for some of the most essential models in quantum magnetism, such as the S=1/2 Heisenberg antiferromagnet in one and two dimensions, as well as extended models useful for studying quantum phase transitions between antiferromagnetic and magnetically disordered states.

•Aug 14, 2016•506 citations

Study of Magnetism in Quantum Spin Systems

Asit Singh

This thesis is divided into 4 chapters. The first chapter gives a brief discussion on the need for the study of Quantum spin systems, and an introduction to Heisenberg Model. In the second chapter, we start the discussion with Quantum entanglement and then go on to show the importance of anti ferromagnetic ground state from the view of entanglement. In the third chapter, we discuss the ways to obtain the ground states of Heisenberg model, both ferromagnet and antiferromagnet. Then we discuss the effect of magnetic field on the antiferromagnetic ground states, for a good understanding of magnetic properties in Chapter(4). In the fourth and the final chapter, we discuss how Bonner Fisher model uses the Bethe ansatz to obtain all the properties of finite Heisenberg chains. Then we analyze the magnetic properties, like Magnetic moment and Susceptibility, of Heisenberg antiferromagnets for finite as well as infinite chains.

•Jan 1, 2011•0 citations

Introduction to quantum spin systems

A. Langari

This manuscript is the collection of lectures given in the summer school on strongly correlated electron systems held at Isfahan university of technology, June 2007. A short overview on quantum magnetism and spin systems is presented. The numerical exact diagonalization (Lanczos) alghorithm is explained in a pedagogical ground. This is a method to get some ground state properties on finite cluster of lattice models. Two extensions of Lanczos method to get the excited states and also finite temperature properties of quantum models are also explained. The basic notions of quantum phase transition is discussed in term of Ising model in transverse field. Its phase diagram and critical properties are explained using the quantum renormalization group approach. Most of the topics are in tutorial level with hints to recent research activities.

Iranian Journal of Physics Research•Jun 15, 2008•1 citation

Computational Studies of Quantum Spin Systems

Anders W. Sandvik, Adolfo Avella, Ferdinando Mancini

These lecture notes introduce quantum spin systems and several computational methods for studying their ground‐state and finite‐temperature properties. Symmetry‐breaking and critical phenomena are first discussed in the simpler setting of Monte Carlo studies of classical spin systems, to illustrate finite‐size scaling at continuous and first‐order phase transitions. Exact diagonalization and quantum Monte Carlo (stochastic series expansion) algorithms and their computer implementations are then discussed in detail. Applications of the methods are illustrated by results for some of the most essential models in quantum magnetism, such as the S = 1/2 Heisenberg antiferromagnet in one and two dimensions, as well as extended models useful for studying quantum phase transitions between antiferromagnetic and magnetically disordered states.

arXiv:1101.3281•AIP conference proceedings•Jan 1, 2010•523 citations

Quantum Monte Carlo methods

David Paul Landau, Kurt Binder

In most of the discussion presented so far in this book, the quantum character of atoms and electrons has been ignored. The Ising spin models have been an exception, but since the Ising Hamiltonian is diagonal (in the absence of a transverse magnetic field), all energy eigenvalues are known and the Monte Carlo sampling can be carried out just as in the case of classical statistical mechanics. Furthermore, the physical properties are in accord with the third law of thermodynamics for Ising-type Hamiltonians (e.g. entropy S and specific heat vanish for temperature T → 0, etc.) in contrast to the other truly classical models dealt with in previous chapters (e.g. classical Heisenberg spin models, classical fluids and solids, etc.) which have many unphysical low temperature properties.

Cambridge University Press eBooks•Jul 29, 2021•0 citations

Quantum Monte Carlo methods

David Paul Landau, Kurt Binder

INTRODUCTION In most of the discussion presented so far in this book, the quantum character of atoms and electrons has been ignored. The Ising spin models have been an exception, but since the Ising Hamiltonian is diagonal (in the absence of a transverse magnetic field!), all energy eigenvalues are known and the Monte Carlo sampling can be carried out just as in the case of classical statistical mechanics. Furthermore, the physical properties are in accord with the third law of thermodynamics for Ising-type Hamiltonians (e.g. entropy S and specific heat vanish for temperature T → 0, etc.) in contrast to the other truly classical models dealt with in previous chapters (e.g. classical Heisenberg spin models, classical fluids and solids, etc.) which have many unphysical low temperature properties. A case in point is a classical solid for which the specific heat follows the Dulong–Petit law, C = 3 Nk B , as T → 0, and the entropy has unphysical behavior since S → – ∞. Also, thermal expansion coefficients tend to non-vanishing constants for T → 0 while the third law implies that they must be zero. While the position and momentum of a particle can be specified precisely in classical mechanics, and hence the groundstate of a solid is a perfectly rigid crystal lattice (motionless particles localized at the lattice points), in reality the Heisenberg uncertainty principle forbids such a perfect rigid crystal, even at T → 0; due to zero point motions which ‘smear out’ the particles over some region around these lattice points.

Cambridge University Press eBooks•Sep 1, 2005•22 citations
These lecture notes give an introduction to quantum magnetism. We start by a discussion of paramagnetism and the Weiss meanfield theory applied to the Ising model. In the following sections, we turn to the fully quantum‐mechanical Heisenberg Hamiltonian. First, we consider the limit of small clusters whose properties we analyze via exact diagonalization. Bulk quantum magnets are then within the framework of the linear spinwave theory. A short discussion of Monte Carlo techniques follows. Finally, we discuss aspects of entanglement in quantum spin systems.
These lecture notes introduce quantum spin systems and several computational methods for studying their ground-state and finite-temperature properties. Symmetry-breaking and critical phenomena are first discussed in the simpler setting of Monte Carlo studies of classical spin systems, to illustrate finite-size scaling at continuous and first-order phase transitions. Exact diagonalization and quantum Monte Carlo (stochastic series expansion) algorithms and their computer implementations are then discussed in detail. Applications of the methods are illustrated by results for some of the most essential models in quantum magnetism, such as the S=1/2 Heisenberg antiferromagnet in one and two dimensions, as well as extended models useful for studying quantum phase transitions between antiferromagnetic and magnetically disordered states.
This thesis is divided into 4 chapters. The first chapter gives a brief discussion on the need for the study of Quantum spin systems, and an introduction to Heisenberg Model. In the second chapter, we start the discussion with Quantum entanglement and then go on to show the importance of anti ferromagnetic ground state from the view of entanglement. In the third chapter, we discuss the ways to obtain the ground states of Heisenberg model, both ferromagnet and antiferromagnet. Then we discuss the effect of magnetic field on the antiferromagnetic ground states, for a good understanding of magnetic properties in Chapter(4). In the fourth and the final chapter, we discuss how Bonner Fisher model uses the Bethe ansatz to obtain all the properties of finite Heisenberg chains. Then we analyze the magnetic properties, like Magnetic moment and Susceptibility, of Heisenberg antiferromagnets for finite as well as infinite chains.
This manuscript is the collection of lectures given in the summer school on strongly correlated electron systems held at Isfahan university of technology, June 2007. A short overview on quantum magnetism and spin systems is presented. The numerical exact diagonalization (Lanczos) alghorithm is explained in a pedagogical ground. This is a method to get some ground state properties on finite cluster of lattice models. Two extensions of Lanczos method to get the excited states and also finite temperature properties of quantum models are also explained. The basic notions of quantum phase transition is discussed in term of Ising model in transverse field. Its phase diagram and critical properties are explained using the quantum renormalization group approach. Most of the topics are in tutorial level with hints to recent research activities.
These lecture notes introduce quantum spin systems and several computational methods for studying their ground‐state and finite‐temperature properties. Symmetry‐breaking and critical phenomena are first discussed in the simpler setting of Monte Carlo studies of classical spin systems, to illustrate finite‐size scaling at continuous and first‐order phase transitions. Exact diagonalization and quantum Monte Carlo (stochastic series expansion) algorithms and their computer implementations are then discussed in detail. Applications of the methods are illustrated by results for some of the most essential models in quantum magnetism, such as the S = 1/2 Heisenberg antiferromagnet in one and two dimensions, as well as extended models useful for studying quantum phase transitions between antiferromagnetic and magnetically disordered states.
In most of the discussion presented so far in this book, the quantum character of atoms and electrons has been ignored. The Ising spin models have been an exception, but since the Ising Hamiltonian is diagonal (in the absence of a transverse magnetic field), all energy eigenvalues are known and the Monte Carlo sampling can be carried out just as in the case of classical statistical mechanics. Furthermore, the physical properties are in accord with the third law of thermodynamics for Ising-type Hamiltonians (e.g. entropy S and specific heat vanish for temperature T → 0, etc.) in contrast to the other truly classical models dealt with in previous chapters (e.g. classical Heisenberg spin models, classical fluids and solids, etc.) which have many unphysical low temperature properties.
INTRODUCTION In most of the discussion presented so far in this book, the quantum character of atoms and electrons has been ignored. The Ising spin models have been an exception, but since the Ising Hamiltonian is diagonal (in the absence of a transverse magnetic field!), all energy eigenvalues are known and the Monte Carlo sampling can be carried out just as in the case of classical statistical mechanics. Furthermore, the physical properties are in accord with the third law of thermodynamics for Ising-type Hamiltonians (e.g. entropy S and specific heat vanish for temperature T → 0, etc.) in contrast to the other truly classical models dealt with in previous chapters (e.g. classical Heisenberg spin models, classical fluids and solids, etc.) which have many unphysical low temperature properties. A case in point is a classical solid for which the specific heat follows the Dulong–Petit law, C = 3 Nk B , as T → 0, and the entropy has unphysical behavior since S → – ∞. Also, thermal expansion coefficients tend to non-vanishing constants for T → 0 while the third law implies that they must be zero. While the position and momentum of a particle can be specified precisely in classical mechanics, and hence the groundstate of a solid is a perfectly rigid crystal lattice (motionless particles localized at the lattice points), in reality the Heisenberg uncertainty principle forbids such a perfect rigid crystal, even at T → 0; due to zero point motions which ‘smear out’ the particles over some region around these lattice points.