Download or read book A Trapped Ion Quantum Simulator for Two dimensional Spin Systems written by Marissa Danielle D'Onofrio and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Universal, fault-tolerant quantum computing would require millions of physical qubits to practically implement most proposed algorithms, a target currently out of reach of experimental capability. In the near term, noisy systems on the order of tens of qubits can employ quantum simulation of particular Hamiltonians to surpass classical computational abilities and solve interesting problems. In particular, one-dimensional (1D) ion chains in radiofrequency (RF) traps have seen remarkable success in simulating 1D quantum spin systems. A comparable ability to manipulate two-dimensional (2D) ion crystals in RF traps would significantly expand the class of systems accessible to quantum simulation. Notably, 2D ion arrays are conducive to studies of many-body systems such as geometrically frustrated lattices, topological materials, and spin-liquid states.In this thesis, I present advances toward the goal of creating programmable, "radial-2D" arrays of trapped 171Yb+ ions for quantum simulation. Qubits are embedded within two hyperfine electronic energy levels, cooled to their motional ground state, and measured via spin-dependent fluorescence. A precisely controlled entangling mechanism allows for the creation of a wide variety of spin models, including Ising or Heisenberg interactions. We present an experimental study which establishes radial-2D crystals of 171Yb+ ions as a robust platform for quantum simulation, through characterization of ion positions, structural phases, normal mode frequencies, and effects from RF heating. We also design and experimentally demonstrate a new open-endcap, blade-style RF trap which can confine and resolve large numbers of ions in the radial-2D crystal phase. Finally, we examine other challenges faced by trapped ion systems: optimally cooling to the motional ground state, accurately determining ion temperature, and measuring susceptibility to the presence of ionizing radiation.
Download or read book Developing Theoretical and Experimental Tools for a Hybrid Quantum Simulator Based on Trapped Ions written by Sainath Motlakunta and published by . This book was released on 2018 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum simulation is the process of using a highly controllable quantum system to simulate another less controllable system. Quantum simulation can provide insights into the properties and dynamics of complex many-body systems. Trapped ion platform is one of the leading candidates for a quantum simulator due to its properties such as ease of isolation, preparation and manipulation. Simulating high dimensional spin systems enables us to study the various physical phenomena in higher geometries. Previous proposals for simulating higher dimensions require experimental resources that don't scale favourably with the system. In this thesis, we propose a hybrid (digital-analog) approach to simulate an effective 2D lattice from a 1D chain of trapped ions. In the initial geometry, the ions interact with each other through a flip-flop kind of interactions generated using a global Molmer-Sorensen scheme. A series of single qubit gates are used to rescale and suppress the interactions in the initial chain to simulate the target geometry. These gates are applied using a laser field gradient which generates a site-dependent AC stark shift. I discuss the construction of this protocol in detail and the theoretical results for the case of 6, 9 and 16 ions. I also show that the number of gates and also the Stark gradient scale linearly with the system size. Experimental implementation of an ion trap quantum simulator has various challenges, one of the which is the laser frequency stabilization within a fraction of transition linewidth. Traditionally, this is done by locking the lasers to an atomic transition. In this thesis, I discuss two alternative schemes for locking the laser frequencies used to build a 171Yb+ ion quantum simulator. One of these solutions uses a commercial wavemeter as a measuring device for the frequency and feedbacks the lasers based on this measurement. I discuss the layout of this scheme and some results. Other solution uses a Fabry Perot (FP) cavity to transfer the stability of a stable laser to an unstable laser. In this thesis, I discuss the construction, optical layout and transmission measurements of a home-built FP cavity.
Download or read book Controlled Inter site Coupling in a Two dimensional Ion Trap Array written by Frederick Hakelberg and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The understanding of quantum mechanical systems is essential to modern physics and its applications. However, already for entangled systems of a few tens of constituents, exact numerical simulations on classical computers can become impossible. Quantum simulators based on well-controlled quantum system might provide the only effective approach to these systems. Trapped atomic ions offer a uniquely precise and controllable platform. They are used as platforms for, e.g., future quantum computers, quantum simulators, and extremely precise clocks. Quantum-simulation problems of interest and out-of-reach for modern theoretical methods include the dynamics of one-dimensional systems on long time scales and more-than-one dimensional systems with long-range interaction. For the latter, two-dimensional arrays of ions, individually trapped and controlled above microfabricated surface-electrode traps, present a promising approach. In the first realizations so far, the inter-site distance between the ions was too large to allow for sufficient inter-site coupling. We aim for a scalable approach to an analog quantum simulator based on a two-dimensional array of individually trapped ions. As a first demonstration, we operate an array of three magnesium ions in triangular arrangement with a side-length of 40μm. Therein, we previously demonstrated the individual control of internal (electronic) and external (motional) degrees of freedom of the ions. Here, we present the first realization of inter-site coupling in the two-dimensional array. We demonstrate the coupling by a transfer of large coherent states of motion between the sites. We investigate the influence of the amplitude of these motional states in the anharmonic trapping potential and extrapolate to future experiments on the single-phonon level. We apply the real-time control of the coupling and concatenate the two-site coupling to transfer motional excitation between all three sites of the array. To demonstrate the scalability of our techniques, we couple all three sites simultaneously and investigate the evolution of an initial excitation at one and two sites of the array. The latter shows interference effects of the different pathways in the triangle. Current motional heating rates on the order of the inter-site coupling, preclude working with single phonons near the motional ground-state. We present a new experimental apparatus and vacuum chamber which will allow in-situ cleaning of surface-electrode traps. This has shown to reduce motional heating rates by two orders of magnitude. In this apparatus, we additionally realize a magnetic-field insensitive qubit in 25Mg+ with a coherence time exceeding six seconds. We generate the magnetic field around 10.9mT by a hybrid magnet assembly based on solid-state magnets and fine-tuned by electric coils. Once we have reduced the heating rate in the triangle trap array using the new setup, first quantum simulation experiments, investigating spin-frustration or artificial gauge fields, will come in reach. Here our triangle represents a basic, scalable, building block of future latices designed at will
Download or read book Studies of Dynamic and Topology of Driven Quantum Many body Systems written by Abhishek Kumar (Physicist) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-equilibrium quantum many-body systems like periodically driven (Floquet) systems exhibit much richer dynamics than their equilibrium counterparts. A striking example is a time crystal, a novel non-equilibrium phase of matter which is forbidden in equilibrium. This thesis concentrates on studying Floquet many-body systems, in particularly, higher-order Floquet topology, light-matter interactions in the Floquet systems, and interesting physics of Floquet many-spin systems with a view towards quantum simulation, e.g. with trapped ions. The model Hamiltonians studied in this thesis are of two types: Floquet-Bloch Hamiltonian and Floquet many-spin Hamiltonian. We report the theoretical discovery and characterization of higher-order Floquet topological phases dynamically generated in a periodically driven system with mirror symmetries. We demonstrate numerically and analytically that these phases support lower-dimensional Floquet bound states, such as corner Floquet bound states at the intersection of edges of a two-dimensional system, protected by the nonequilibrium higher-order topology induced by the periodic drive. We characterize higher-order Floquet topologies of the bulk Floquet Hamiltonian using mirror-graded Floquet winding number. We also show that bulk vortex structures can be dynamically generated by a spatially inhomogeneous drive and can host multiple Floquet bound states. Inspired by the effectiveness of the optical probes in condensed matter systems, we study the light-matter interactions in Floquet systems in strong and weak optical field regimes. In the weak field limit, we formulate the linear response theory of a periodically driven system. We illustrate the applications of this formalism by giving general expressions for optical conductivity of Floquet systems, including its homodyne and heterodyne components and beyond. We obtain the Floquet optical conductivity of specific driven models, including two-dimensional Dirac material such as the surface of a topological insulator, graphene, and the Haldane model irradiated with circularly or linearly polarized laser, as well as a semiconductor quantum well driven by an ac potential. In the strong field limit, we formulate a theory of bulk optical current for a periodically driven system, which accounts for the mixing of external drive and laser field frequencies and, therefore, the broadening of the harmonic spectrum compared to the undriven system. We illustrate the application of this theory by studying high harmonic generation in the periodically driven Su Schrieffer-Heeger model. We find significant enhancement in higher harmonics when the system is driven, even for low field amplitudes and obtain harmonics forbidden in the undriven model. Motivated by applications on a trapped-ion quantum simulator, we study many-spin systems with periodically driven two-body interactions and external fields in the high-frequency limit. We show that a hierarchy of multi-spin interactions can be generated in powers of inverse-frequency, such as Dzyaloshinskii-Moriya interaction (DMI), three- and four-spin interactions, and additional Zeeman terms. We introduce the concept of a Floquet gauge pump where we exploit the dynamically generated interactions of a Floquet Hamiltonian to detect the topology of the ground state and edge states in interacting systems. We demonstrate this concept in 1D XY model with periodically driven couplings and a transverse field and discuss the requirements to realize the Floquet gauge pump with trapped ions.
Download or read book Quantum Simulations with 8 8 Sr Ions on Planar Lattice Traps written by Ziliang Carter Lin and published by . This book was released on 2008 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum simulations are the use of well controlled many-body quantum systems to simulate and solve other many-body quantum systems that are not understood. This thesis describes theoretical proposals and experimental progress towards simulating quantum spin Hamiltonians with trapped SSSr+ ions on microfabricated planar lattice traps. These types of quantum simulations help solve exponentially complex quantum systems, which are challenging to current classical computers. Porras and Cirac's work has shown that off-resonance laser light couples the internal states of the trapped ions with their external motional states; the external states of the ions are coupled through their Coulomb repulsion. Therefore the internal states of ions can be mapped to effective spin states and spin coupling is mediated by phonons. I propose two simulation schemes for quantum spin Hamiltonians in two dimensions: the time evolution of a spin state in a system of three ions with ferromagnetic interaction and spin frustration in a triangle. To realize these proposals, I design and microfabricate a hexagonal lattice trap and install it into an ultrahigh vacuum chamber. This thesis also presents the construction of the experimental test apparatus for the trapped ion quantum simulator, including the electronics, optics, and vacuum systems.
Download or read book Particle Creation and Memory Effects in a Trapped Ion Quantum Simulator written by Matthias Wittemer and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The fundamental laws of quantum mechanics are far from our everyday life experiences. However, they have been extremely successful in explaining observations in microscopic physical systems and are, already, harnessed for several applications. Moreover, in combination with relativistic considerations, basic phenomena from quantum mechanics are accredited a central role in the (macroscopic) evolution of our universe. In this thesis, we employ a trapped ion quantum simulator to experimentally investigate two fundamental quantum mechanical effects that have been extensively studied for many decades. In the first investigation, we implement non-adiabatic changes of the ions' trapping potential in order to amplify quantum vacuum fluctuations. Following theoretical works by others, this mechanism can be interpreted as an analog to the creation of particles during cosmic inflation in the early universe. Such cosmological particles are considered as the seeds for the formation of the large-scale structures in our universe that we observe nowadays. In our analog quantum simulation, the creation of particles is evidenced by the detection of a squeezed state in the motion of the ions. A remarkable feature of this mechanism is the accompanying creation of quantum entanglement. In case of the cosmological particles, this entanglement spreads over large, cosmic distances. In the second investigation, we benchmark a theoretical concept in the framework of open quantum systems in a most basic system and under near-ideal conditions. In nature, any quantum system inevitably interacts with its environment and, thereby, needs ultimately to be considered an open system that can build up correlations and, even, entanglement with its environment. We implement a spin-1/2 system in the electronic degree of freedom of a single trapped ion, which we couple to a bosonic environment, formed by a motional degree of freedom of the ion. Further, we implement a tunable interaction between system and environment that, in turn, can lead to entanglement. By performing measurements on the open system only, we observe quantum non-Markovian behavior, which we quantify using a rigorously defined measure. Thereby, we reveal that the quantification of such quantum memory effects is fundamentally limited by fundamental quantum mechanical measurement uncertainties. The investigations presented in this thesis significantly expand the capabilities of our trapped ion platform to perform ana ...
Download or read book Quantum Computer Systems written by Yongshan Ding and published by Springer Nature. This book was released on 2022-05-31 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book targets computer scientists and engineers who are familiar with concepts in classical computer systems but are curious to learn the general architecture of quantum computing systems. It gives a concise presentation of this new paradigm of computing from a computer systems' point of view without assuming any background in quantum mechanics. As such, it is divided into two parts. The first part of the book provides a gentle overview on the fundamental principles of the quantum theory and their implications for computing. The second part is devoted to state-of-the-art research in designing practical quantum programs, building a scalable software systems stack, and controlling quantum hardware components. Most chapters end with a summary and an outlook for future directions. This book celebrates the remarkable progress that scientists across disciplines have made in the past decades and reveals what roles computer scientists and engineers can play to enable practical-scale quantum computing.
Download or read book Quantum Computing written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-04-27 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum mechanics, the subfield of physics that describes the behavior of very small (quantum) particles, provides the basis for a new paradigm of computing. First proposed in the 1980s as a way to improve computational modeling of quantum systems, the field of quantum computing has recently garnered significant attention due to progress in building small-scale devices. However, significant technical advances will be required before a large-scale, practical quantum computer can be achieved. Quantum Computing: Progress and Prospects provides an introduction to the field, including the unique characteristics and constraints of the technology, and assesses the feasibility and implications of creating a functional quantum computer capable of addressing real-world problems. This report considers hardware and software requirements, quantum algorithms, drivers of advances in quantum computing and quantum devices, benchmarks associated with relevant use cases, the time and resources required, and how to assess the probability of success.
Download or read book Quantum Measurement and Control written by Howard M. Wiseman and published by Cambridge University Press. This book was released on 2010 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern quantum measurement for graduate students and researchers in quantum information, quantum metrology, quantum control and related fields.
Download or read book Introduction to Many Body Physics written by Piers Coleman and published by Cambridge University Press. This book was released on 2015-11-26 with total page 815 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern, graduate-level introduction to many-body physics in condensed matter, this textbook explains the tools and concepts needed for a research-level understanding of the correlated behavior of quantum fluids. Starting with an operator-based introduction to the quantum field theory of many-body physics, this textbook presents the Feynman diagram approach, Green's functions and finite-temperature many-body physics before developing the path integral approach to interacting systems. Special chapters are devoted to the concepts of Fermi liquid theory, broken symmetry, conduction in disordered systems, superconductivity and the physics of local-moment metals. A strong emphasis on concepts and numerous exercises make this an invaluable course book for graduate students in condensed matter physics. It will also interest students in nuclear, atomic and particle physics.
Download or read book Quantum Foundations And Open Quantum Systems Lecture Notes Of The Advanced School written by Theo M Nieuwenhuizen and published by World Scientific. This book was released on 2014-10-03 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced School on Quantum Foundations and Open Quantum Systems was an exceptional combination of lectures. These comprise lectures in standard physics and investigations on the foundations of quantum physics.On the one hand it included lectures on quantum information, quantum open systems, quantum transport and quantum solid state. On the other hand it included lectures on quantum measurement, models for elementary particles, sub-quantum structures and aspects on the philosophy and principles of quantum physics.The special program of this school offered a broad outlook on the current and near future fundamental research in theoretical physics.The lectures are at the level of PhD students.
Download or read book Manipulating Quantum Systems written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-09-14 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of atomic, molecular, and optical (AMO) science underpins many technologies and continues to progress at an exciting pace for both scientific discoveries and technological innovations. AMO physics studies the fundamental building blocks of functioning matter to help advance the understanding of the universe. It is a foundational discipline within the physical sciences, relating to atoms and their constituents, to molecules, and to light at the quantum level. AMO physics combines fundamental research with practical application, coupling fundamental scientific discovery to rapidly evolving technological advances, innovation and commercialization. Due to the wide-reaching intellectual, societal, and economical impact of AMO, it is important to review recent advances and future opportunities in AMO physics. Manipulating Quantum Systems: An Assessment of Atomic, Molecular, and Optical Physics in the United States assesses opportunities in AMO science and technology over the coming decade. Key topics in this report include tools made of light; emerging phenomena from few- to many-body systems; the foundations of quantum information science and technologies; quantum dynamics in the time and frequency domains; precision and the nature of the universe, and the broader impact of AMO science.
Download or read book Quantum Enhanced Nonlinear Spectroscopy written by Frank Schlawin and published by Springer. This book was released on 2016-09-10 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on nonlinear spectroscopy from a quantum optics perspective. First, it provides a detailed introduction to nonlinear optical signals; starting from Glauber’s photon counting formalism, it establishes the diagrammatic formulation, which forms the backbone of nonlinear molecular spectroscopy. The main body of the thesis investigates the impact of quantum correlations in entangled photon states on two-photon transitions, with a particular focus on the time-energy uncertainty, which restricts the possible simultaneous time and frequency resolution in measurements. It found that this can be violated with entangled light for individual transitions. The thesis then presents simulations of possible experimental setups that could exploit this quantum advantage. The final chapter is devoted to an application of the rapidly growing field of multidimensional spectroscopy to trapped ion chains, where it is employed to investigate nonequilibrium properties in quantum simulations.
Download or read book Quantum Enhanced Sensing Based on Time Reversal of Entangling Interactions written by Daniel Linnemann and published by Springer. This book was released on 2018-07-28 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum mechanics entails effects like superpositions and entanglement, which have no classical counterparts. From a technological standpoint these counterintuitive quantum aspects can be viewed as an unexploited resource that can be harnessed to support various tasks, e.g. in the domains of computation, communication, and metrology. In many applications, however, the potential of nonclassical states cannot practically be exploited due to detection inefficiencies. The authors address this limitation by experimentally realizing a novel detection scheme in which entangling interactions are time reversed. In this way, nonclassical many-particle states are disentangled, allowing them to be detected in a robust and technically feasible manner. In the context of quantum metrology, these nonlinear readout techniques extend the class of entangled probe states that can be leveraged for sensing applications without being limited by finite detector resolution. The authors present an active atom interferometer, where both the entangled state preparation and disentangling readout involve parametric amplification. This “SU(1,1)” interferometer is implemented with the help of spinor Bose–Einstein condensates, where amplification is implemented by atomic collisions leading to spin exchange.
Download or read book Ultracold Atoms in Optical Lattices written by Maciej Lewenstein and published by Oxford University Press. This book was released on 2012-03-08 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the physics of atoms frozen to ultralow temperatures and trapped in periodic light structures. It introduces the reader to the spectacular progress achieved on the field of ultracold gases and describes present and future challenges in condensed matter physics, high energy physics, and quantum computation.
Download or read book A Single Trapped Rydberg Ion written by Gerard Higgins and published by Springer Nature. This book was released on 2019-10-22 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Systems of trapped ions and systems of ultracold Rydberg atoms are used at the forefront of quantum physics research and they make strong contenders as platforms for quantum technologies. Trapped Rydberg ions are a new hybrid technology envisaged to have both the exquisite control of trapped ion systems and the strong interactions of Rydberg atoms. In this work a single trapped Rydberg ion is experimentally investigated. A trapped strontium ion is excited to Rydberg states using two ultraviolet lasers. Effects of the strong trapping electric fields on the highly-sensitive Rydberg ion are studied. After mitigating unwanted trap effects, the ion is coherently excited to Rydberg states and a quantum gate is demonstrated. This thesis lays much of the experimental groundwork for research using this novel system.
Download or read book Equilibrium and Nonequilibrium Aspects of Phase Transitions in Quantum Physics written by Ricardo Puebla and published by Springer. This book was released on 2018-09-17 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the equilibrium and nonequilibrium properties of continuous phase transitions are studied in various systems, with a special emphasis on understanding how well-established universal traits at equilibrium may be extended into the dynamic realm, going beyond the paradigmatic Kibble–Zurek mechanism of defect formation. This book reports on the existence of a quantum phase transition in a system comprising just a single spin and a bosonic mode (the quantum Rabi model). Though critical phenomena are inherent to many-body physics, the author demonstrates that this small and ostensibly simple system allows us to explore the rich phenomenology of phase transitions, both in- and out-of-equilibrium. Moreover, the universal traits of this quantum phase transition may be realized in a single trapped-ion experiment, thus avoiding the need to scale up the number of constituents. In this system, the phase transition takes place in a suitable limit of system parameters rather than in the conventional thermodynamic limit – a novel notion that the author and his collaborators have dubbed the finite-component system phase transition. As such, the results gathered in this book will open promising new avenues in our understanding and exploration of quantum critical phenomena.
