Quantum Phase Transitions in Multi-Impurity and Lattice Kondo Systems
Author: Ammar Nejati
Publisher:
Published: 2017
Total Pages:
ISBN-13:
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Understanding Quantum Phase Transitions
Author: Lincoln Carr
Publisher: CRC Press
Published: 2010-11-02
Total Pages: 756
ISBN-13: 1439802610
DOWNLOAD EBOOKQuantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivit
Quantum Scaling in Many-Body Systems
Author: Mucio Continentino
Publisher: Cambridge University Press
Published: 2017-04-17
Total Pages: 249
ISBN-13: 1107150256
DOWNLOAD EBOOKFocusing on experimental results, this updated edition approaches the problem of quantum phase transitions from a new and unifying perspective.
Quantum Phase Transitions
Author: Subir Sachdev
Publisher: Cambridge University Press
Published: 2001-04-23
Total Pages: 374
ISBN-13: 9780521004541
DOWNLOAD EBOOKQuantum Phase Transitions is the first book to describe in detail the fundamental changes that can occur in the macroscopic nature of matter at zero temperature due to small variations in a given external parameter. The subject plays a central role in the study of the electrical and magnetic properties of numerous important solid state materials. The author begins by developing the theory of quantum phase transitions in the simplest possible class of non-disordered, interacting systems - the quantum Ising and rotor models. Particular attention is paid to their non-zero temperature dynamic and transport properties in the vicinity of the quantum critical point. Several other quantum phase transitions of increasing complexity are then discussed and clarified. Throughout, the author interweaves experimental results with presentation of theoretical models, and well over 500 references are included. The book will be of great interest to graduate students and researchers in condensed matter physics.
Impurity Quantum Phase Transitions in Quantum Dot Nanostructures
Author: Lucas Bernd Marie Peeters
Publisher:
Published: 2019
Total Pages:
ISBN-13:
DOWNLOAD EBOOKElectronic systems subject to competing interactions can end up in different phases as the balance between these interactions shifts. When a quantum critical point separates these phases, exotic electronic behavior often marks the vicinity of the transition. In this work, we construct nanopatterned devices to probe such critical phenomena. The basic element of our devices is the GaAs/AlGaAs quantum dot, an isolated region of electronic charge which is coupled to a two-dimensional gas of weakly interacting electrons. We use different designs of quantum dots to realize different models. The first device studied in this work realizes the spin two-channel Kondo ('spin 2CK') model. In this model, a single impurity (i.e. a single spin-degenerate dot) is coupled to two separate reservoirs. When the couplings to both reservoirs are unequal, the more strongly coupled reservoir screens the impurity spin degeneracy and forms a many-body singlet; this is known as the Kondo effect. When both reservoirs are coupled equally strongly, a non-Fermi liquid ground state arises as a result of the overscreening by both reservoirs. We probe the anomalous scaling properties of this state, and show how it transitions into a more conventional Fermi liquid under the influence of various perturbations. The second device is first operated as a single metallic quantum dot in the quantum Hall regime. Spin degeneracy is broken, but the device can be tuned such that there is now a charge degeneracy which can then be screened by coupling to a reservoir. We tune to and away from equal couplings to see the effect of the two-channel Kondo state. Finally, we operate the second device in its full form as a double-dot device, to explore the competition between dot-lead and interdot interactions.
Quantum Scaling in Many-Body Systems
Author: Mucio Continentino
Publisher: Cambridge University Press
Published: 2017-04-17
Total Pages: 249
ISBN-13: 110818412X
DOWNLOAD EBOOKQuantum phase transitions are strongly relevant in a number of fields, ranging from condensed matter to cold atom physics and quantum field theory. This book, now in its second edition, approaches the problem of quantum phase transitions from a new and unifying perspective. Topics addressed include the concepts of scale and time invariance and their significance for quantum criticality, as well as brand new chapters on superfluid and superconductor quantum critical points, and quantum first order transitions. The renormalisation group in real and momentum space is also established as the proper language to describe the behaviour of systems close to a quantum phase transition. These phenomena introduce a number of theoretical challenges which are of major importance for driving new experiments. Being strongly motivated and oriented towards understanding experimental results, this is an excellent text for graduates, as well as theorists, experimentalists and those with an interest in quantum criticality.
Quantum Phase Transitions in Impurity Models and Percolating Lattices
Author: Manal M. Al-Ali
Publisher:
Published: 2013
Total Pages: 119
ISBN-13:
DOWNLOAD EBOOK"This thesis investigates the influence of random disorder and dissipation on zero-temperature quantum phase transitions. Both phenomena can fundamentally change the character of the phases of a quantum many-particle system and of the transitions between them. If dissipation and disorder occur simultaneously in a system undergoing a quantum phase transition, particularly strong effects can be expected. In the first paper reproduced in this thesis, we study a single quantum rotor coupled to a sub-Ohmic dissipative bath. We find that this system undergoes a quantum phase transition from a delocalized phase to a localized phase as the dissipation strength is increased. We determine the exact critical behavior of this transition; it agrees with that of the corresponding long-range interacting classical model. Therefore, the quantum-to-classical mapping is valid for the sub-Ohmic rotor model. In the second paper, we investigate the influence of sub-Ohmic dissipation on randomly diluted quantum Ising and rotor models. We find that the zero-temperature quantum phase transition across the lattice percolation threshold separates an unusual super-paramagnetic cluster phase from an inhomogeneous ferromagnetic phase. We determine the low-temperature thermodynamic behavior in both phases, and we relate our results to the smeared transition scenario for disordered quantum phase transitions. In the last paper, the influence of Ohmic dissipation on the random transverse-field Ising chain is studied by means of large-scale Monte-Carlo simulations. Our simulations show that Ohmic dissipation destroys the infinite-randomness quantum critical point of the dissipationless system. Instead, the quantum phase transition between the paramagnetic and ferromagnetic phases is smeared, as predicted by a recent strong-disorder renormalization group approach"--Abstract, page iv.
Quantum Ising Phases and Transitions in Transverse Ising Models
Author: Sei Suzuki
Publisher: Springer
Published: 2012-12-14
Total Pages: 407
ISBN-13: 3642330398
DOWNLOAD EBOOKQuantum phase transitions, driven by quantum fluctuations, exhibit intriguing features offering the possibility of potentially new applications, e.g. in quantum information sciences. Major advances have been made in both theoretical and experimental investigations of the nature and behavior of quantum phases and transitions in cooperatively interacting many-body quantum systems. For modeling purposes, most of the current innovative and successful research in this field has been obtained by either directly or indirectly using the insights provided by quantum (or transverse field) Ising models because of the separability of the cooperative interaction from the tunable transverse field or tunneling term in the relevant Hamiltonian. Also, a number of condensed matter systems can be modeled accurately in this approach, hence granting the possibility to compare advanced models with actual experimental results. This work introduces these quantum Ising models and analyses them both theoretically and numerically in great detail. With its tutorial approach the book addresses above all young researchers who wish to enter the field and are in search of a suitable and self-contained text, yet it will also serve as a valuable reference work for all active researchers in this area.
Lectures On Phase Transitions
Author: A S Shumovsky
Publisher: World Scientific
Published: 1990-11-30
Total Pages: 253
ISBN-13: 9814507660
DOWNLOAD EBOOKThis book treats the problem of phase transitions, emphasizing the generality and universality of the methods and models used. The course is basically concentrated on the problems of vacuum degeneration in macroscopic systems and a fundamental concept of quasiaverages by Bogolubov playing a special role in the theory of phase transitions and critical phenomena. An analysis of the connection between phase transition and spontaneous symmetry breaking in a macroscopic system allows a unique description of both first- and second-order phase transitions.The unique features of this book are:(i) a unique approach of describing first — as well as second-order phase transitions, based on the Bogolubov concept of quasi-averages.(ii) a detailed presentation of the material and at the same time a review of modern problems.(iii) a general character of developed ideas that could be applied to various particular systems of condensed matter physics, nuclear physics and high-energy physics.
Topological Phase Transitions And New Developments
Author: Lars Brink
Publisher: World Scientific
Published: 2018-08-13
Total Pages: 263
ISBN-13: 9813271353
DOWNLOAD EBOOKGeometry and topology have been a fascination in physics since the start of the 20th century. A leading example is Einstein's geometrical theory of gravity. At the beginning of the 1970s, topological ideas entered areas of condensed matter physics. These advances were driven by new seminal ideas resolving a serious contradiction between experiment and the standard interpretation of a rigorous mathematical theorem which led to the study of new exotic topological phases of matter. Topological defect driven phase transitions in thin, two dimensional films of superfluids, superconductors and crystals have provided great insight into the mechanism governing these topological phases present in those physical systems. Moreover, many of these topological properties remain 'protected' against disorder and topological distortion perturbations. An example of possible applications of such robustness to perturbations is in the search for encoding information in quantum computers, potentially providing the platform for fault-tolerant quantum computations.In the past four decades, the discovery of topological phases engendered great interest in condensed matter physics. It also attracted the attention of researchers working on quantum information, quantum materials and simulations, high energy physics and string theory. This unique volume contains articles written by some of the most prominent names in the field, including Nobel Laureate John Michael Kosterlitz and Professor Jorge V José. They originate from talks and discussions by leading experts at a recent workshop. They review previous works as well as addressing contemporary developments in the most pressing and important issues on various aspects of topological phases and topological phase transitions.
