Download or read book Quantum Simulations with Ultracold Atoms Beyond Standard Optical Lattices written by Philipp Hans-Jürgen Hauke and published by . This book was released on 2013 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many outstanding problems in quantum physics, such as high-Tc superconductivity or quark confinement, are still - after decades of research - awaiting commonly accepted explanations. One reason is that such systems are often difficult to control, show an intermingling of several effects, or are not easily accessible to measurement. To arrive at a deeper understanding of the physics at work, researchers typically derive simplified models designed to capture the most striking phenomena of the system under consideration. However, due to the exponential complexity of Hilbert space, even some of the simplest of such models pose formidable challenges to analytical and numerical calculations. In 1982, Feynman proposed to solve such quantum models with experimental simulation on a physically distinct, specifically engineered quantum system [Int. J. Theor.Phys. 21, 467]. Designed to be governed by the same underlying equations as the original model, it is hoped that direct measurements on these so called quantum simulators (QSs) will allow to gather deep insights into outstanding problems of physics and beyond. In this thesis, we identify four requirements that a useful QS has to fulfill, relevance, control, reliability, and efficiency. Focusing on these, we review the state of the art of two popular approaches, digital QSs (i.e., special purpose quantum computers) and analog QSs (devices with always-on interactions). Further, focusing on possibilities to increase control over QSs, we discuss a scheme to engineer quantum correlations between mesoscopic numbers of spinful particles in optical lattices. This technique, based on quantum polarization spectroscopy, may be useful for state preparation and quantum information protocols. Additionally, employing several analytical and numerical methods for the calculation of many-body ground states, we demonstrate the variety of condensed-matter problems that can be attacked with QSs consisting of ultracold ions or neutral atoms in optical lattices. The chosen examples, some of which have already been realized in experiment, include such diverse settings as frustrated antiferromagnetism, quantum phase transitions in exotic lattice geometries, topological insulators, non-Abelian gauge-fields, orbital order of ultracold Fermions, and systems with long-range interactions. The experimental realization of all of these models requires techniques which go beyond standard optical lattices, e.g., time-periodic driving of lattices with exotic geometry, loading ultracold atoms into higher bands, or immersing trapped ions into an optical lattice. The chosen models, motivated by important open questions of quantum physics, pose difficult problems for classical computers, but they may be amenable in the near future to quantum simulation with ultracold atoms or ions. While the experimental control over relevant models has increased dramatically in the last years, the reliability and efficiency of QSs has received considerably less attention. As a second important part of this thesis, we emphasize the need to consider these aspects under realistic experimental conditions. We discuss specific situations where terms that have typically been neglected in the description of the QS introduce systematic errors and even lead to novel physics. Further, we characterize in a generic example the influence of quenched disorder on an analog QS. Its performance for simulating universal behavior near a quantum phase transition seems satisfactory for low disorder. Moreover, our results suggest a connection between the reliability and efficiency of a QS: it works less reliable exactly in those interesting regimes where classical calculations are less efficient. If QSs fulfill all of our four requirements, they may revolutionize our approach to quantum-mechanical problems, allowing to solve the behavior of complex Hamiltonians, and to design nano-scale materials and chemical compounds from the ground up.

Download or read book Quantum Simulation Using Ultracold Atoms in Two dimensional Optical Lattices written by Sarah Al-Assam and published by . This book was released on 2010 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultracold Atoms in Optical Lattices written by Maciej Lewenstein and published by Oxford University Press, USA. This book was released on 2017-04-13 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum computers, though not yet available on the market, will revolutionize the future of information processing. Quantum computers for special purposes like quantum simulators are already within reach. The physics of ultracold atoms, ions and molecules offer unprecedented possibilities of control of quantum many body systems and novel possibilities of applications to quantum information processing and quantum metrology. Particularly fascinating is the possibility of using ultracold atoms in lattices to simulate condensed matter or even high energy physics. This book provides a complete and comprehensive overview of ultracold lattice gases as quantum simulators. It opens up an interdisciplinary field involving atomic, molecular and optical physics, quantum optics, quantum information, condensed matter and high energy physics. The book includes some introductory chapters on basic concepts and methods, and then focuses on the physics of spinor, dipolar, disordered, and frustrated lattice gases. It reviews in detail the physics of artificial lattice gauge fields with ultracold gases. The last part of the book covers simulators of quantum computers. After a brief course in quantum information theory, the implementations of quantum computation with ultracold gases are discussed, as well as our current understanding of condensed matter from a quantum information perspective.

Download or read book Ultracold Atoms in Optical Lattices written by Maciej Lewenstein and published by OUP Oxford. This book was released on 2012-03-08 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum computers, though not yet available on the market, will revolutionize the future of information processing. Quantum computers for special purposes like quantum simulators are already within reach. The physics of ultracold atoms, ions and molecules offer unprecedented possibilities of control of quantum many body systems and novel possibilities of applications to quantum information processing and quantum metrology. Particularly fascinating is the possibility of using ultracold atoms in lattices to simulate condensed matter or even high energy physics. This book provides a complete and comprehensive overview of ultracold lattice gases as quantum simulators. It opens up an interdisciplinary field involving atomic, molecular and optical physics, quantum optics, quantum information, condensed matter and high energy physics. The book includes some introductory chapters on basic concepts and methods, and then focuses on the physics of spinor, dipolar, disordered, and frustrated lattice gases. It reviews in detail the physics of artificial lattice gauge fields with ultracold gases. The last part of the book covers simulators of quantum computers. After a brief course in quantum information theory, the implementations of quantum computation with ultracold gases are discussed, as well as our current understanding of condensed matter from a quantum information perspective.

Download or read book Ultracold Bosons in Optical Lattices for Quantum Measurement and Simulation written by William Cody Burton and published by . This book was released on 2019 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultracold atoms provide a platform that allows for pristine control of a physical system, and have found uses in both the fields of quantum measurement and quantum simulation. Optical lattices, created by the AC Stark shift of a coherent laser beam, are a versatile tool to control ultracold atoms and implement novel Hamiltonians. In this thesis, I report on three experiments using the bosonic species Rubidium-87 trapped in optical lattices. I first discuss our work in simulating the Harper-Hofstadter Hamiltonian, which describes charged particles in high magnetic fields, and has connections to topological physics. To simulate the charged particles, we use laser-assisted tunneling to add a complex phase to tunneling in the optical lattice. For the first time, we have condensed bosons into the ground state of the Harper-Hofstadter Hamiltonian. In addition, we have demonstrated that we can add strong on-site interactions to the effective Hamiltonian, opening the door to studies of interesting states near the Mott insulator transition. Next, I present a novel technique to preserve phase coherence between separated quantum systems, called superfluid shielding. Phase coherence is important for both quantum measurement and simulation, and is fundamentally limited by projection noise. When an interacting quantum system is split, frozen-in number fluctuations lead to fluctuations of the relative phase between separated subsystems. We cancel the effect of these fluctuations by immersing the separated subsystems in a common superfluid bath, and demonstrate that we can increase coherence lifetime beyond the projection noise limit. Finally, I discuss our efforts in simulating magnetic ordering in the spin-1 Heisen- berg Hamiltonian. It is hard to adiabatically ramp into magnetically ordered ground states, because they often have gapless excitations. Instead, we use a spin-dependent lattice to modify interspin interactions, allowing us to ramp into the spin Mott insulator, which has a gap and can therefore act as a cold starting point for exploration of the rest of the phase diagram. We have achieved a cold spin temperature in the spin Mott insulator, and I discuss plans to also achieve a cold charge temperature and then ramp to the the xy-ferromagnet, which has spin-charge separation.

Download or read book Quantum Simulation of Triangular Honeycomb and Kagome Crystal Structures using Ultracold Atoms in Lattices of Laser Light written by Claire K Thomas and published by . This book was released on 2005 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultracold atomic gases trapped at the interference of coherent beams of light constitute an artificial material. This optical lattice material may be used for controlled quantum simulations of condensed matter theories. The bulk of this dissertation concerns the construction and calibration of an optical superlattice that can form the triangular, honeycomb and kagome crystal structures. The properties and geometry of this artificial material may be dynamically changed, allowing for the experiments discussed in this thesis that would be impossible with real materials. The use of ultracold atoms in optical lattices for quantitative tests is challenging because of the novelty of many of the techniques in the field, and because of the myriad experimental differences between these artificial materials and true materials. This thesis reports the development of a method to characterize optical lattice potentials using matter-wave diffraction. We observe an enhancement of inversion asymmetry in matter-wave diffraction from a honeycomb lattice, which we explain using a time-independent perturbative treatment of the single-particle band structure of the lattice. Our experiment also provides new insight into a commonly used detection technique. This thesis culminates in the development and experimental realization of a quantitative test of a condensed-matter theory. The test is insensitive to the experimental differences between artificial materials and real materials. We focus on a prediction from a mean-field treatment of the Bose-Hubbard model that concerns the difference in behavior of itinerant particles on lattices that are identical but for their geometry. Using the tunable geometry of our quantum simulator, we measure the properties of ultracold atomic gases trapped in the triangular and kagome lattices under otherwise identical conditions and find that they are consistent with the mean-field scaling prediction.

Download or read book Quantum Many Body Physics of Ultracold Molecules in Optical Lattices written by Michael L. Wall and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates ultracold molecules as a resource for novel quantum many-body physics, in particular by utilizing their rich internal structure and strong, long-range dipole-dipole interactions. In addition, numerical methods based on matrix product states are analyzed in detail, and general algorithms for investigating the static and dynamic properties of essentially arbitrary one-dimensional quantum many-body systems are put forth. Finally, this thesis covers open-source implementations of matrix product state algorithms, as well as educational material designed to aid in the use of understanding such methods.

Download or read book Creating Novel Quantum States of Ultracold Bosons in Optical Lattices written by Colin Joseph Kennedy and published by . This book was released on 2017 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultracold atoms in optical lattices are among the most developed platforms of interest for building quantum devices suitable for quantum simulation and quantum computation. Ultracold trapped atoms are advantageous because they are fundamentally indistinguishable qubits that can be prepared with high fidelity in well-defined states and read-out with similarly high fidelities. However, an outstanding challenge for ultracold atoms in optical lattices is to engineer interesting interactions and control the effects of heating that couple the system to states that lie outside the Hilbert space we wish to engineer. In this thesis, I describe a series of experiments and theoretical proposals that address several critical issues facing ultracold atoms in optical lattices. First, I describe experiments where the tunneling behavior of atoms in the lattice is modified to make our fundamentally neutral particles behave as though they are charged particles in a magnetic field. We show how engineering this interaction creates intrinsic degeneracy in the single particle spectrum of the many-body system and how to introduce strong interactions in the system with the goal of producing exotic many-body states such as a bosonic fractional quantum Hall states. Then, I discuss how this technique can be easily generalized to include spin and higher spatial dimensions in order to access a rich variety of new physics phenomena. Next, I report on the realization of a spin-1 Heisenberg Hamiltonian which emerges as the low energy effective theory describing spin ordering in the doubly-occupied Mott insulator of two spin components. This integer spin Heisenberg model is qualitatively different from the half-integer spin model because it contains a gapped, spin-insulating ground state for small inter-spin interaction energies which we call the spin Mott. Using a spin-dependent lattice to control the inter-spin interactions, we demonstrate high-fidelity, reversible loading of the spin-Mott phase and develop a probe of local spin correlations in order to demonstrate a spin entropy below 0.2 kB per spin. Progress on adiabatically driving the quantum phase transition from the spin Mott to the xy-ferromagnetic is discussed along with the progress towards the creation of a quantum gas microscope for single atom detection and manipulation..

Download or read book Quantum Simulations with Ultracold Quantum Gases written by Zhihao Lan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantum Many Body Physics of Ultracold Molecules in Optical Lattices written by Michael L. Wall and published by Springer. This book was released on 2015-04-20 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates ultracold molecules as a resource for novel quantum many-body physics, in particular by utilizing their rich internal structure and strong, long-range dipole-dipole interactions. In addition, numerical methods based on matrix product states are analyzed in detail, and general algorithms for investigating the static and dynamic properties of essentially arbitrary one-dimensional quantum many-body systems are put forth. Finally, this thesis covers open-source implementations of matrix product state algorithms, as well as educational material designed to aid in the use of understanding such methods.

Download or read book Quantum Simulation with Ultracold Atoms Solid state Models and Beyond written by Dirk-Sören Lühmann and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantum Simulations with Neutral Atoms in Optical Lattices written by Matthias Rosenkranz and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cold Atoms and Permanent Magnetic Lattices written by Saeed Ghanbari and published by LAP Lambert Academic Publishing. This book was released on 2010-01 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is divided into two parts. The first one deals with the Bose-Hubbard model which describes the dynamics of ultracold atoms in periodic potentials such as optical and magnetic lattices. These lattices have potential application in quantum information processing since they can provide storage registers for qubits based on neutral atoms. Simulation of ultracold Bose gases in lattices using gauge P representation, which is an exact quantum phase space method, is discussed in the book. Simulations that are in remarkable agreement with other calculations in limiting cases are presented in the book. The second part of the book dealing with permanent magnetic lattices provides a comprehensive overview of them. The author describes lattices of microtraps for trapping and controlling Bose-Einstein condensates (BECs) and quantum gases. High trap frequencies and therefore the possibility of creating BECs at a fraction of mK is an advantage of magnetic lattices over optical lattices. Graduate students in condensed matter and atomic physics as well as both newcomers and experts in the exciting fields of quantum-atom optics and quantum information are encouraged to reed this book.

Download or read book Hubbard Model The Recent Results written by Mario G Rasetti and published by World Scientific. This book was released on 1991-07-03 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of articles provides authoritative and up-to-date reviews on the Hubbard Model. It will be useful to graduate students and researchers in the field.

Download or read book Ultra cold Atoms in Optical Lattices written by Richard Walters and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical methods for atomic quantum gases written by Anna Minguzzi and published by Edizioni della Normale. This book was released on 2004-10-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The achievement of Bose-Einstein condensation in ultra-cold vapours of alkali atoms has given enormous impulse to the study of dilute atomic gases in condensed quantum states inside magnetic traps and optical lattices. High purity and easy optical access make them ideal candidates to investigate fundamental issues on interacting quantum systems. This review presents some theoretical issues which have been addressed in this area and the numerical techniques which have been developed and used to describe them, from mean-field models to classical and quantum simulations for equilibrium and dynamical properties. The attention given in this article to methods beyond standard mean-field approaches should make it a useful reference point for future advances in these areas.

Download or read book Quantum Many body Dynamics of Ultracold Atoms in Optical Lattices written by Stefan Keßler and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: