Download or read book Microscopic Description of Two Dimensional Dipolar Quantum Gases written by Adrián Macía Rey and published by . This book was released on 2015 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: A microscopic description of the many-body properties of anisotropic homogeneous gases of bosonic dipoles in two dimensions is presented and discussed. By changing the polarization angle with respect to the plane, we study the impact of the anisotropy, present in the dipole-dipole interaction on different physical quantities. We restrict the analysis to the range of polarization angles where the interaction is always repulsive, although the strength of the repulsion can be strongly dependent on the orientation with respect to the polarization field. We present a study of the zero energy two-body problem which allows us to find the scattering length of the interaction and to build a suitable Jastrow many-body wave function that will be used as a trial wave function for Monte Carlo simulations of the bulk two-dimensional system of bosonic dipoles. In the first part of this work we have studied the low-density dipolar Bose gas and we find that the anisotropy has an almost negligible impact on the ground state properties of the many-body system in the universal regime where the scattering length governs the physics of the system. We also show that scaling in the gas parameter persists in the dipolar case up to values where other isotropic interactions with the same scattering length yield different predictions. We also evaluate the excitation spectrum of the dipolar Bose gas in the context of the Feynman approximation and compare the results obtained with the Bogoliubov ones. As expected, we find that these two approximations agree at very low densities, while they start to deviate from each other as the density increases. When the density of the system is increased we find that the behavior of the system depends on the value of the polarization angle of the dipolar moments of the system. At large densities and moderate values of the polarization angle the system undergoes a first-order quantum phase transition from a gas and a crystal phase. We also find that the anisotropy of the dipole-dipole potential causes an elongation of the crystalline lattice of the system in the direction where the interaction is stronger. At large polarization angles and moderate densities the system undergoes a second-order quantum phase transition from a gas to a stripe phase. Interestingly, the critical exponents of this second order transition are nearly independent of the tilting angle and are compatible with the 3D Ising and 3D XY model universality classes within the statistical uncertainty of our simulations. Finally, at high densities and large tilting angles the system shows a first order phase transition between the crystal and stripe phases. The slope of this transition curve is extremely large indicating that, due to the anisotropy of the interaction, the crystal phase of the system is no longer stable if the dipole - dipole potential is highly anisotropic. We consider the ground state of a bilayer system of dipolar bosons, which is a configuration consisting in the continement of the particles in two paralel planes by means of a trapping potential. We consider the simplest situation where dipole moments are oriented by an external field in the direction perpendicular to the parallel planes. Quantum Monte Carlo methods are used to calculate the ground-state energy, the one-body and two-body density matrix as a function of the separation between layers. We find that by decreasing the interlayer distance for fixed value of the strength of the dipolar interaction, the behavior of all the physical observables studied are compatible with the existence of a second order phase transition modulated by the inter-layer distance. In this sense, the results presented in this work are in good agreement with some previous studies of dipolar gases in a bilayer setup.
Download or read book Microscopic Description of Confined Bosonic Dipolar Quantum Gases in Two Dimensions written by Juan Sánchez Baena and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a microscopic description of the two dimensional quantum few body problem involving confined polarized bosons. Due to anisotropy of the dipolar interaction, the system presents an interesting behaviour in terms of crystalline structure formation. Focusing on the polarization tilting angles that do not make the system collapse, the competition between the anisotropy of the confining trap and the one of the dipolar interaction results in a variety of particle arrangements, which becomes wider when considering variation on the trap strength. We intend to characterize these structures both in the quantum and in the classical cases, in order to make a comparison between both. We will present first the theoretical framework to solve the problem, which involves finding the two-body dipolar wave function in order to build a suitable trial wave function for the complete problem, a brief review of the numerical Monte Carlo and Simulated Annealing methods used and an analysis of the results, which will consist on a variety of crystalline structures in terms of three key parameters: the trap strength, the tilting angle for dipoles and the anisotropy of the confining trap. Focus will be put in making a structural diagram for one particular strength in order to provide a more accurate description of the stable structures in terms of the two other parameters (tilting and trap anisotropy). We will show that, despite the classical system and the quantum one not differing much, there are certain regions in the structural diagram in which both systems do show different particle arrangements.
Download or read book Theory of a Nearly Two dimensional Dipolar Bose Gas written by Michael A. Woulfe and published by . This book was released on 2016 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project develops a theoretical model for gases of bosonic atoms at ultracold, but finite temperatures. Under these circumstances, the gas can undergo a phase transition to a purely quantum mechanical state, a Bose-Einstein condensate (BEC), where the atoms cease to behave like distinguishable entities, and instead form a single macroscopic matter wave. At exactly zero temperature, all of the atoms occupy the BEC; at finite temperatures, a significant fraction of the atoms leave the BEC and form a thermal cloud. Thus, the state of a low, but finite-temperature gas of bosonic atoms involves the coexistence of a BEC and a thermal cloud. Further, the atoms can interact in a variety of different ways, which have important consequences for the state of the gas. We consider both short range contact interactions and dipolar interactions, where the atoms interact via the long-range anisotropic dipole-dipole force. We develop this model in both three- and two-dimensional geometries.
Download or read book Cold Molecules written by Roman Krems and published by CRC Press. This book was released on 2009-06-25 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: The First Book on Ultracold MoleculesCold molecules offer intriguing properties on which new operational principles can be based (e.g., quantum computing) or that may allow researchers to study a qualitatively new behavior of matter (e.g., Bose-Einstein condensates structured by the electric dipole interaction). This interdisciplinary book discusse
Download or read book Microscopic Theory of Semiconductors written by Stephan W. Koch and published by World Scientific. This book was released on 1995 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: The articles in this book review recent developments in the microscopic theory of optical and electronic semiconductor properties. Many advances in this active field are intimately related to the work of Hartmut Haug and his coworkers. At the occasion of Haug's 60th birthday, a number of current and/or former members of his research team review the current state-of-the-art. Topics include the quantum kinetics of electrons, phonons and photons, coherent optical effects, quantum transport, ballistic motion, microscopic semiconductor laser theory with special emphasis on microlasers, symmetry aspects of laser excited semiconductors, as well as a review of the two-dimensional Wigner crystal in a strong magnetic field. The articles present the material in sufficient detail to be understandable by advanced graduate students and researchers who have a good background in quantum mechanics.
Download or read book Macroscopic States of Dipolar Quantum Gases written by Matthias Wenzel and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Gas Experiments Exploring Many body States written by Paivi Torma and published by World Scientific. This book was released on 2014-09-16 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum phenomena of many-particle systems are fascinating in their complexity and are consequently not fully understood and largely untapped in terms of practical applications. Ultracold gases provide a unique platform to build up model systems of quantum many-body physics with highly controlled microscopic constituents. In this way, many-body quantum phenomena can be investigated with an unprecedented level of precision, and control and models that cannot be solved with present day computers may be studied using ultracold gases as a quantum simulator.This book addresses the need for a comprehensive description of the most important advanced experimental methods and techniques that have been developed along with the theoretical framework in a clear and applicable format. The focus is on methods that are especially crucial in probing and understanding the many-body nature of the quantum phenomena in ultracold gases and most topics are covered both from a theoretical and experimental viewpoint, with interrelated chapters written by experts from both sides of research.Graduate students and post-doctoral researches working on ultracold gases will benefit from this book, as well as researchers from other fields who wish to gain an overview of the recent fascinating developments in this very dynamically evolving field. Sufficient level of both detailed high level research and a pedagogical approach is maintained throughout the book so as to be of value to those entering the field as well as advanced researchers. Furthermore, both experimentalists and theorists will benefit from the book; close collaboration between the two are continuously driving the field to a very high level and will be strengthened to continue the important progress yet to be made in the field.
Download or read book Sketches of Physics written by Roberta Citro and published by Springer Nature. This book was released on 2023-10-16 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a journey through the wonders of physics, the special thousandth volume of the renowned Lecture Notes in Physics book series. From quantum physics to solar physics, this volume showcases the beauty of physics in various fields. Written by series editors and colleagues, these essays are accessible to non-specialists and graduate-level students alike, making for an intriguing read for anyone interested in learning about physics beyond their own field of study. Explore the historical development of the series with two insightful forewords. List of essays: A New Era of Quantum Materials Mastery and Quantum Simulators In and Out of Equilibrium Evaluation and Utility of Wilsonian Naturalness The Geometric Phase: Consequences in Classical and Quantum Physics The Coming Decades of Quantum Simulation Insights into Complex Functions Exploring the Hottest Atmosphere with the Parker Solar Probe A Primer on the Riemann Hypothesis
Download or read book Solid State Physics written by Joginder Singh Galsin and published by Academic Press. This book was released on 2019-02-23 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid State Physics: An Introduction to Theory presents an intermediate quantum approach to the properties of solids. Through this lens, the text explores different properties, such as lattice, electronic, elastic, thermal, dielectric, magnetic, semiconducting, superconducting and optical and transport properties, along with the structure of crystalline solids. The work presents the general theory for most of the properties of crystalline solids, along with the results for one-, two- and three-dimensional solids in particular cases. It also includes a brief description of emerging topics, such as the quantum hall effect and high superconductivity. Building from fundamental principles and requiring only a minimal mathematical background, the book includes illustrative images and solved problems in all chapters to support student understanding. Provides an introduction to recent topics, such as the quantum hall effect, high-superconductivity and nanomaterials Utilizes the Dirac' notation to highlight the physics contained in the mathematics in an appropriate and succinct manner Includes many figures and solved problems throughout all chapters to provide a deeper understanding for students Offers topics of particular interest to engineering students, such as elasticity in solids, dislocations, polymers, point defects and nanomaterials
Download or read book Cold Chemistry written by Olivier Dulieu and published by Royal Society of Chemistry. This book was released on 2017-12-12 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the theoretical and experimental aspects of cold and ultracold molecular collisions, for students and researchers in theoretical chemistry and chemical reaction/molecular dynamics.
Download or read book Enhanced Optical and Electric Manipulation of a Quantum Gas of KRb Molecules written by Jacob P. Covey and published by Springer. This book was released on 2018-10-01 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes significant advances in experimental capabilities using ultracold polar molecules. While ultracold polar molecules are an idyllic platform for quantum chemistry and quantum many-body physics, molecular samples prior to this work failed to be quantum degenerate, were plagued by chemical reactions, and lacked any evidence of many-body physics. These limitations were overcome by loading molecules into an optical lattice to control and eliminate collisions and hence chemical reactions. This led to observations of many-body spin dynamics using rotational states as a pseudo-spin, and the realization of quantum magnetism with long-range interactions and strong many-body correlations. Further, a 'quantum synthesis' technique based on atomic insulators allowed the author to increase the filling fraction of the molecules in the lattice to 30%, a substantial advance which corresponds to an entropy-per-molecule entering the quantum degenerate regime and surpasses the so-called percolations threshold where long-range spin propagation is expected. Lastly, this work describes the design, construction, testing, and implementation of a novel apparatus for controlling polar molecules. It provides access to: high-resolution molecular detection and addressing; large, versatile static electric fields; and microwave-frequency electric fields for driving rotational transitions with arbitrary polarization. Further, the yield of molecules in this apparatus has been demonstrated to exceed 10^5, which is a substantial improvement beyond the prior apparatus, and an excellent starting condition for direct evaporative cooling to quantum degeneracy.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2002 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Frontiers of Engineering written by National Academy of Engineering and published by National Academies Press. This book was released on 2019-02-28 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents papers on the topics covered at the National Academy of Engineering's 2018 US Frontiers of Engineering Symposium. Every year the symposium brings together 100 outstanding young leaders in engineering to share their cutting-edge research and innovations in selected areas. The 2018 symposium was held September 5-7 and hosted by MIT Lincoln Laboratory in Lexington, Massachusetts. The intent of this book is to convey the excitement of this unique meeting and to highlight innovative developments in engineering research and technical work.
Download or read book Lectures on Light Nonlinear and Quantum Optics Using the Density Matrix written by Stephen Rand and published by Oxford University Press. This book was released on 2010-06-17 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A textbook which thoroughly introduces the density matrix formalism and applies it to a range of topics of current interest constitutes a 'missing link' among quantum optics textbooks."-Christoph Becher, Saarland University, Germany --
Download or read book Quantum Many Body Physics in Open Systems Measurement and Strong Correlations written by Yuto Ashida and published by Springer Nature. This book was released on 2020-01-06 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book studies the fundamental aspects of many-body physics in quantum systems open to an external world. Recent remarkable developments in the observation and manipulation of quantum matter at the single-quantum level point to a new research area of open many-body systems, where interactions with an external observer and the environment play a major role. The first part of the book elucidates the influence of measurement backaction from an external observer, revealing new types of quantum critical phenomena and out-of-equilibrium dynamics beyond the conventional paradigm of closed systems. In turn, the second part develops a powerful theoretical approach to study the in- and out-of-equilibrium physics of an open quantum system strongly correlated with an external environment, where the entanglement between the system and the environment plays an essential role. The results obtained here offer essential theoretical results for understanding the many-body physics of quantum systems open to an external world, and can be applied to experimental systems in atomic, molecular and optical physics, quantum information science and condensed matter physics.
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1972 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Bureau of Standards 1972 Catalog written by United States. National Bureau of Standards and published by . This book was released on 1973 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
