Download or read book Phase Transitions and Real Time Dynamics of Spin and Charge Densities in One Dimensional Correlated Systems written by Michael Sekania and published by . This book was released on 2011 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phase Transitions in Spin Systems written by Linji Yang and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Spin systems are powerful mathematical models widely used and studied in Statistical Physics and Computer Science. This thesis focuses the study of spin systems on colorings and weighted independent sets (the hard-core model). In many spin systems, there exist phase transition phenomena: there is a threshold value of a parameter such that when the parameter is on one side of the threshold, the system exhibits the so-called spatial decay of correlation, i.e., the influence from a set of vertices to another set of vertices diminishes as the distance between the two sets grows; when the parameter is on the other side, long range correlations persist. The uniqueness problem and the reconstruction problem are two major threshold problems that are concerned with the decay of correlations in the Gibbs measure from different perspectives. In Computer Science, the study of spin systems mainly focused on finding an efficient algorithm that samples the configurations from a distribution that is very close to the Gibbs measure. Glauber dynamics is a typical Markov chain algorithm for performing sampling. In many systems, the convergence time of the Glauber dynamics also exhibits a threshold behavior: the speed of convergence experiences a dramatic change around the threshold of the parameter. The first two parts of this thesis focus on making connections between the phase transition of the convergence time of the dynamics and the phase transition of the reconstruction phenomenon in both colorings and the hard-core model on regular trees. A relatively sharp threshold is established for the change of the convergence time, which coincides with the reconstruction threshold. A general technique of upper bounding the conductance of the dynamics via analyzing the sensitivity of the reconstruction algorithm is proposed and proven to be very effective for lower bounding the convergence time of the dynamics. The third part of the thesis provides an innovative analytical method for establishing a strong version of the decay of correlation of the Gibbs distributions for many two spin systems on various classes of graphs. In particular, the method is applied to the hard-core model on the square lattice, a very important graph that is of great interest in both Statistical Physics and Computer Science. As a result, we significantly improve the lower bound of the uniqueness threshold on the square lattice and extend the range of parameter where the Glauber dynamics is rapidly mixing.
Download or read book Dynamics at Solid State Surfaces and Interfaces Volume 1 written by Uwe Bovensiepen and published by John Wiley & Sons. This book was released on 2010-11-29 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume work covers ultrafast structural and electronic dynamics of elementary processes at solid surfaces and interfaces, presenting the current status of photoinduced processes. Providing valuable introductory information for newcomers to this booming field of research, it investigates concepts and experiments, femtosecond and attosecond time-resolved methods, as well as frequency domain techniques. The whole is rounded off by a look at future developments.
Download or read book The Lie Algebras su N written by Walter Pfeifer and published by Birkhäuser. This book was released on 2012-12-06 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lie algebras are efficient tools for analyzing the properties of physical systems. Concrete applications comprise the formulation of symmetries of Hamiltonian systems, the description of atomic, molecular and nuclear spectra, the physics of elementary particles and many others. This work gives an introduction to the properties and the structure of the Lie algebras su(n). The book features an elementary (matrix) access to su(N)-algebras, and gives a first insight into Lie algebras. Student readers should be enabled to begin studies on physical su(N)-applications, instructors will profit from the detailed calculations and examples.
Download or read book Journal of the Physical Society of Japan written by and published by . This book was released on 2004 with total page 998 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Methods in Computational Quantum Mechanics written by Ilya Prigogine and published by John Wiley & Sons. This book was released on 2009-09-09 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of quantum chemistry for the quantitative prediction of molecular properties has long been frustrated by the technical difficulty of carrying out the needed computations. In the last decade there have been substantial advances in the formalism and computer hardware needed to carry out accurate calculations of molecular properties efficiently. These advances have been sufficient to make quantum chemical calculations a reliable tool for the quantitative interpretation of chemical phenomena and a guide to laboratory experiments. However, the success of these recent developments in computational quantum chemistry is not well known outside the community of practitioners. In order to make the larger community of chemical physicists aware of the current state of the subject, this self-contained volume of Advances in Chemical Physics surveys a number of the recent accomplishments in computational quantum chemistry. This stand-alone work presents the cutting edge of research in computational quantum mechanics. Supplemented with more than 150 illustrations, it provides evaluations of a broad range of methods, including: * Quantum Monte Carlo methods in chemistry * Monte Carlo methods for real-time path integration * The Redfield equation in condensed-phase quantum dynamics * Path-integral centroid methods in quantum statistical mechanics and dynamics * Multiconfigurational perturbation theory-applications in electronic spectroscopy * Electronic structure calculations for molecules containing transition metals * And more Contributors to New Methods in Computational Quantum Mechanics KERSTIN ANDERSSON, Department of Theoretical Chemistry, Chemical Center, Sweden DAVID M. CEPERLEY, National Center for Supercomputing Applications and Department of Physics, University of Illinois at Urbana-Champaign, Illinois MICHAEL A. COLLINS, Research School of Chemistry, Australian National University, Canberra, Australia REINHOLD EGGER, Fakultät für Physik, Universität Freiburg, Freiburg, Germany ANTHONY K. FELTS, Department of Chemistry, Columbia University, New York RICHARD A. FRIESNER, Department of Chemistry, Columbia University, New York MARKUS P. FÜLSCHER, Department of Theoretical Chemistry, Chemical Center, Sweden K. M. HO, Ames Laboratory and Department of Physics, Iowa State University, Ames, Iowa C. H. MAK, Department of Chemistry, University of Southern California, Los Angeles, California PER-ÅKE Malmqvist, Department of Theoretical Chemistry, Chemical Center, Sweden MANUELA MERCHán, Departamento de Química Física, Universitat de Valéncia, Spain LUBOS MITAS, National Center for Supercomputing Applications and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Illinois STEFANO OSS, Dipartimento di Fisica, Università di Trento and Istituto Nazionale di Fisica della Materia, Unità di Trento, Italy KRISTINE PIERLOOT, Department of Chemistry, University of Leuven, Belgium W. THOMAS POLLARD, Department of Chemistry, Columbia University, New York BJÖRN O. ROOS, Department of Theoretical Chemistry, Chemical Center, Sweden LUIS SERRANO-ANDRÉS, Department of Theoretical Chemistry, Chemical Center, Sweden PER E. M. SIEGBAHN, Department of Physics, University of Stockholm, Stockholm, Sweden WALTER THIEL, Institut für Organische Chemie, Universität Zürich, Zürich, Switzerland GREGORY A. VOTH, Department of Chemistry, University of Pennsylvania, Pennsylvania C. Z. Wang, Ames Laboratory and Department of Physi
Download or read book Lectures on Spin Dynamics written by Giuseppe Pileio and published by Royal Society of Chemistry. This book was released on 2022-06-13 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of a series of lectures introducing what the author believes to be the theoretical minimum for the understanding of nuclear spin dynamics, the branch of physics underpinning magnetic resonance techniques such as NMR and MRI. Spin dynamics ultimately concern the study of the state and time evolution of systems made by a large collection of particles possessing spin, one of the most subtle and indeed fascinating concepts in relativistic quantum mechanics and whose understanding requires a mix of quantum mechanics, Hamiltonian dynamics and advanced mathematics. Written in the concise and direct style appropriate for university lectures, this book is addressed to both undergraduate and postgraduate students who are approaching magnetic resonance studies and want to reach the theoretical minimum required to understand the wider topic and its main applications. The book is suitable for researchers who work in the field of magnetic resonance and want to know more about its theoretical fundamentals. Finally, built as a complete set of 12 lectures and 4 workshops, the book can act as a solid reference to lecturers of magnetic resonance university modules. Trained in a world-leading research laboratory internationally recognised for its contributions to the NMR field, the author has a track record in theoretical and methodological developments of nuclear spin dynamics. In this book, he tries to merge his passion for the understanding of physics through its mathematical rendering with his personal quest for the elegance of a clean, clear and satisfactory explanation.
Download or read book Phases and Phase Transitions of Strongly Correlated Electron Systems written by Pouyan Ghaemi Mohammadi and published by . This book was released on 2008 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Different experiments on strongly correlated materials have shown phenomena which are not consistent with our conventional understandings. We still do not have a general framework to explain these properties. Developing such a general framework is much beyond the scope of this thesis, but here we try to address some of challenges in simpler models that are more tractable. In correlated metals it appears as strong correlations have different effect on different parts of fermi surface. Perhaps most striking example of this is normal state of optimally doped cuprates; the quasiparticle peaks on the nominal fermi surface do not appear uniformly. We try to track such phenomena in heavy fermion systems, which are correlated fermi liquids. In these systems, a lattice of localized electrons in f or d orbitals is coupled to the conduction electrons through an antiferromagnetic coupling. Singlets are formed between localized and conduction electrons. This singlet naturally have non-zero internal angular momentum. This nontrivial structure leads to anisotropic effect of strong correlations. Internal structure of Kondo singlet can also lead to quantum Hall effect in Kondo insulator, and formation of isolated points on the fermi surface with fractionalized quasiparticles. In the second part we study a phase transition in Heisenberg model between two insulating phases, Neel ordered and certain spin liquid state, popular in theories of the cuprates. The existence of such a transition has a number of interesting implications for spin liquid based approaches to the underdoped cuprates and clarifies existing ideas for incorporating antiferromagnetic long range order into such a spin liquid based approach. This transition might also be enlightening, despite fundamental differences, for the heavy fermion critical points where a second order transition between the heavy fermion phase and a metallic phase with magnetic antiferromagnetic order is observed.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Frustrated Spin Systems 2nd Edition written by Hung-the Diep and published by World Scientific. This book was released on 2013-03-25 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers all principal aspects of currently investigated frustrated systems, from exactly solved frustrated models to real experimental frustrated systems, going through renormalization group treatment, Monte Carlo investigation of frustrated classical Ising and vector spin models, low-dimensional systems, spin ice and quantum spin glass. The reader can — within a single book — obtain a global view of the current research development in the field of frustrated systems.This new edition is updated with recent theoretical, numerical and experimental developments in the field of frustrated spin systems. The first edition of the book appeared in 2005. In this edition, more recent works until 2012 are reviewed. It contains nine chapters written by researchers who have actively contributed to the field. Many results are from recent works of the authors.The book is intended for postgraduate students as well as researchers in statistical physics, magnetism, materials science and various domains where real systems can be described with the spin language. Explicit demonstrations of formulas and full arguments leading to important results are given where it is possible to do so.
Download or read book Annual Review written by 岡崎国立共同研究機構分子科学研究所 and published by . This book was released on 2002 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electronic Structure and Collective Excitations in Correlated Materials written by Felix Tilman Schmitt and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In condensed matter, electrons are not independent but are coupled to their neighbors via interactions; they are said to be correlated. This fact that electronic states are aware of their neighbors' states and changes thereof gives rise to a rich variety of properties and physics that defines the nature around us. Correlations in condensed matter can range in their effect from slight changes in the band structure to the emergence of order and symmetry breaking, which lead to novel properties and phases. These correlations exhibit themselves on different time scales. Mott-insulators, in which strong Coulomb repulsion between electrons splits a half-filled conduction band to result in an insulator, can have a band gap of several eV. On the other hand, transitions into the superconducting or charge density wave state, for example, happen on energy scales within several tens to hundreds of meV of EF. Despite the plethora of phenomena arising from these correlations, this many-body problem is hard to tackle and there is still much to be learned. This work investigates different aspects of correlated systems in and out of equilibrium with angle resolved photoemission (ARPES), and time resolved ARPES, two powerful spectroscopic techniques that are able to elucidate the dynamics and mechanics of correlations. Starting out, the experimental ARPES setup is introduced, and the ARPES system located in the Geballe Laboratory for Advanced Materials at Stanford University is described in more detail, since its maintenance and enhancement were an integral part of this work. In the following, the high energy properties of Nd2-xCexCuO4+d (NCCO) are investigated with ARPES. NCCO belongs to the electron doped side of a class of materials called high temperature superconducting Cuprates (HTSCs), so called because of their unusually high transition temperatures. The HTSCs exhibit a plethora of rich physics; including the anti-ferromagnetic insulating phase of the undoped parent compound dominated by Mott-Hubbard physics to the superconducting dome which features superconductivity with a d-wave symmetry whose origin is still a mystery. The hole doped HTSCs show a vertical band dispersion in ARPES measurements around 0.3 eV which was termed the high energy anomaly (HEA). Here, a systematic study of high energy features on NCCO revealed a similar HEA, albeit around 0.6 eV binding energy. We were able to successfully explain the HEA within the Hubbard model as being a cross-over from the quasi particle band resulting from doping and the lower or upper Hubbard band, depending on doping. The simulations also captured the difference in energy scale between hole and electron doping. Next, focusing on energies within several tens of meV of EF, a different energy scale of NCCO is explored. In the hole doped HTSCs, a discontinuity of the electronic dispersion around 50-70 meV was observed both in the region of the Brillouin zone were the d-wave superconducting gap had a node ("nodal") and where it had a maximum ("antinodal"). Conversely, in the electron doped materials this kink could only be observed in the antinodal region. If the discontinuity or "kink", which is hypothesized to originate from electron phonon coupling to certain Oxygen modes, is related to superconductivity, one would imagine it to have the same universality as the observed superconductivity. Our work demonstrates that new and improved ARPES data show a kink in the nodal region of NCCO as well, giving this discontinuity universality among the HTSCs. Superconductivity (SC) (at least conventional, electron phonon mediated superconductivity according to Bardeen-Cooper-Schrieffer) is closely related to its brethren, the spin- (SDW) or charge-density waves (CDW): all are mediated by different channels of the same type of interaction. The non-equilibrium dynamics and excitation modes of CDWs and SCs are closely related. Time resolved ARPES (tr-ARPES) is able to probe both non-equilibrium dynamics and collective excitation modes in real time. Continuing, this work explores the non-equilibrium physics of TbTe3, a model system for studying charge density waves. Our systematic study of the transient dynamics in dependence of excitation density revealed a complex picture ranging all the way from a weakly perturbed regime, in which collective modes were evident to a strongly perturbed regime, where we could observe the transient melting of the CDW state. This unprecedented insight into the dynamics of interactions will enhance our future understanding of correlated materials. Through the strengths of tr-ARPES, we were able to assign one of the collective modes we observed to the amplitude mode of the CDW. This provides a major stepping stone towards seeing a similar amplitude mode in superconductors. Especially in novel superconductors like the HTSCs or the Pnictides, where the mechanism of superconductivity is still debated, the observation of such collective modes could greatly aid towards their understanding which is needed in order to eventually exploit their huge potential for real-life applications.
Download or read book Dynamical Properties of Quasi One Dimensional Correlated Electron Systems written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Correlated electrons in one spatial dimension have very unusual properties such as the dynamical separation of spin and charge degrees of freedom. Typically, dynamical correlation functions of these systems are investigated with field theoretical methods that are valid in the limit of vanishingly low energies. However, there are few reliable results at finite energies which can be directly compared with spectra of scattering experiments, such as angle-resolved photoemission. It has therefore been difficult to find direct spectroscopic evidence of spin-charge separation in experimental realizations of quasi one-dimensional electron systems. The Dynamical Density-Matrix Renormalization Group can accurately determine spectral properties of correlated one-dimensional lattice models for all energy scales and interaction strengths. We use this method to determine the frequency- and momentum dependent correlation functions of extended Hubbard Hamiltonians. We obtain results for various quantities including the optical conductivity, the one-particle spectral function, dynamical charge- and spin structure factors.
Download or read book Density matrix Renormalization group Studies of Spin Boson and Fermion Systems with Symmetry protected Topological Phases written by Florian Lange and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Matrix-product-state based methods, in particular the density-matrix renormalization group, are used to numerically investigate several one-dimensional systems, focusing on models with symmetry-protected topological phases that generalize the spin-1 Haldane chain. In the first part, ground state properties such as topological order parameters and the criticality at quantum phase transitions are studied. The second part deals with dynamic properties of spin chains. Using time-dependent matrix-product-state calculations, the dynamic structure factor, and the transport properties of contacted spin chains are analyzed.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 1006 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Science Abstracts written by and published by . This book was released on 1992 with total page 1228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Condensed Matter Field Theory written by Alexander Altland and published by Cambridge University Press. This book was released on 2010-03-11 with total page 785 pages. Available in PDF, EPUB and Kindle. Book excerpt: This primer is aimed at elevating graduate students of condensed matter theory to a level where they can engage in independent research. Topics covered include second quantisation, path and functional field integration, mean-field theory and collective phenomena.
