Download or read book Noise Correlations and Coherent Coupling in Solid state Qubits written by David Marcos and published by . This book was released on 2011 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Computing in Solid State Systems written by Berardo Ruggiero and published by Springer Science & Business Media. This book was released on 2006-05-30 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Computation in Solid State Systems discusses experimental implementation of quantum computing for information processing devices; in particular observations of quantum behavior in several solid state systems are presented. The complementary theoretical contributions provide models of minimizing decoherence in the different systems. Most recent theoretical and experimental results on macroscopic quantum coherence of mesoscopic systems, as well as the realization of solid-state qubits and quantum gates are discussed. Particular attention is given to coherence effects in Josephson devices. Other solid state systems---including quantum dots, optical, ion, and spin devices---are also discussed.
Download or read book Decoherence of Spatially Separated Quantum Bits written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work investigates the decoherence of a qubit register caused by spatially correlated quantum noise and develops theoretical tools to describe the associated reduced qubit dynamics. The environment that causes decoherence of the qubit states is modeled as a bosonic field. The non-local qubit-field coupling explicitly takes effects from a finite propagation time of field distortions between separated qubits into account. A natural realization of this model is the coupling of quantum dot spin and charge qubits to phonons of the underlying substrate. One part of the work concentrates on the case where the bath fluctuations induce pure dephasing of the qubit states. For this problem the reduced qubit dynamics possesses an exact solution which is presented in explicit form. A main focus is put on (i) the short-time dynamics of a single qubit which in the standard description with exponential decay rates shows up as a reduced initial amplitude of coherent qubit oscillations, and (ii) the consequences of a spatial qubit separation of several qubits for bipartite qubit entanglement and the register fidelity. In a second part it is shown that a direct application of the Bloch-Redfield theory to a spatially extended system of qubits leads to a violation of causality and predicts spurious decoherence-free subspaces. We reveal why this approach fails and derive a non-Markovian causal master equation that captures the main effects of the spatial separation. Compared to general non-Markovian master equations, the causal master equation has the advantage of being more intuitive and of allowing for algebraic methods, e.g. within a symmetry analysis. Finally, using the causal master equation approach the decoherence of two spatially separated qubits subject to bit-flip noise is studied. We investigate how spatial noise correlations influence the relaxation of entangled solid-state qubits. It is shown that by collective exchange of bosons via a thermal one-dimensional environment.
Download or read book Quantum Coherence in Solid State Systems written by Benoît Deveaud and published by IOS Press. This book was released on 2009 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume gives an overview of the manifestations of quantum coherence in different solid state systems, including semiconductor confined systems, magnetic systems, crystals and superconductors. Besides being of paramount importance in fundamental physics, the study of quantum coherence furnishes the starting point for important applications like quantum computing or secure data transmission. The coherent effects discussed mainly involve elementary excitations in solids like polaritons, excitons, magnons, macroscopic quantities like superconductor currents and electron spins. Also, several new aspects of the physics of quasi-particles are understood and discussed in this context. Due to the variety of systems in which quantum coherence may be observed, solid state systems are the natural candidates for applications that rely on coherence, for example quantum computer." --Book Jacket.
Download or read book Quantum Correlation and Decoherence in Quantum Computation written by and published by . This book was released on 2014 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, I will investigate the correlations in the noise source and in the qubit system. Although noise correlation is generally thought to be harmful, in a classical noise correlation model that I will suggest, it will be shown that the correlation of classical telegraph noise might actually lead to improved performance. On the other hand, quantum correlation between qubits seems to be a crucial part of quantum speed-up. The minimal involvement of quantum entanglement in certain quantum algorithms (Phys. Rev. A, 72, 042316) led to the suggestion of the new type of quantum correlation, quantum discord. I will show that the calculation of the geometric global quantum discord is an NP-hard problem. For the states of the special form, I will suggest a numerical method to calculate geometric global quantum discord. It was shown that quantum discord persists longer under noisy environment than quantum entanglement and it suddenly changes its behavior and starts to decay faster (sudden transition) (Phys. Rev. A, 80, 044102, Phys. Rev. Lett., 104, 200401). The condition for this behavior had been shown for two-qubit Bell diagonal states, and I will show that the similar condition holds for the more general multi-partite state and randomly chosen 2-qubit states have only a small chance to observe the sudden transition and it becomes exponentially rarer as the number of qubits increases. Finally, I will investigate a two-qubit operation that induces quantum coherence using capacitive coupling. I will suggest that two-qubit operation based on capacitive coupling might be done more efficiently in a parameter regime previously not explored. But after considering more realistic restrictions such as slow quasi-static $1/f$ noise and finite pulse rise-time, I will show the two-qubit operation is not expected to perform sufficiently well.
Download or read book Nanophysics Coherence and Transport written by and published by Elsevier. This book was released on 2005-08-02 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: The developments of nanofabrication in the past years have enabled the design of electronic systems that exhibit spectacular signatures of quantum coherence. Nanofabricated quantum wires and dots containing a small number of electrons are ideal experimental playgrounds for probing electron-electron interactions and their interplay with disorder. Going down to even smaller scales, molecules such as carbon nanotubes, fullerenes or hydrogen molecules can now be inserted in nanocircuits. Measurements of transport through a single chain of atoms have been performed as well. Much progress has also been made in the design and fabrication of superconducting and hybrid nanostructures, be they normal/superconductor or ferromagnetic/superconductor. Quantum coherence is then no longer that of individual electronic states, but rather that of a superconducting wavefunction of a macroscopic number of Cooper pairs condensed in the same quantum mechanical state. Beyond the study of linear response regime, the physics of non-equilibrium transport (including non-linear transport, rectification of a high frequency electric field as well as shot noise) has received much attention, with significant experimental and theoretical insights. All these quantities exhibit very specific signatures of the quantum nature of transport, which cannot be obtained from basic conductance measurements. Basic concepts and analytical tools needed to understand this new physics are presented in a series of theoretical fundamental courses, in parallel with more phenomenological ones where physics is discussed in a less formal way and illustrated by many experiments.· Electron-electron interactions in one-dimensional quantum transport· Coulomb Blockade and Kondo physics in quantum dots· Out of equilibrium noise and quantum transport· Andreev reflection and subgap nonlinear transport in hybrid N/S nanosructures.· Transport through atomic contacts · Solid state Q-bits · Written by leading experts in the field, both theorists and experimentalists
Download or read book Realizing Controllable Quantum States Proceedings Of The International Symposium On Mesoscopic Superconductivity And Spintronics In The Light Of Quantum Computation written by Junsaku Nitta and published by World Scientific. This book was released on 2005-08-02 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a collection of papers from the third meeting of the international symposium on mesoscopic superconductivity and spintronics. Research on quantum information technology has advanced a great deal since the previous meeting. Mesoscopic physics, such as spins in nano-scale semiconductor structures, micro-fabricated superconducting junctions and extraordinary metal contacts have now been not only theoretically but also experimentally established as important solid-state elements of quantum information devices. The book also contains some papers on information theory from the viewpoint of quantum algorithms, indicating that further collaboration between physics and computer science promises to produce fruitful results in quantum information technology.
Download or read book Quantum Noise in Mesoscopic Physics written by Yuli V. Nazarov and published by Springer Science & Business Media. This book was released on 2003-04-30 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is written to conclude the NATO Advanced Research Workshop "Quantum Noise in Mesoscopic Physics" held in Delft, the Netherlands, on June 2-4, 2002. The workshop was co-directed by M. Reznikov of Israel Institute of Technology, and me. The members of the organizing committee were Yaroslav Blanter (Delft), Chirstopher Glattli (Saclay and ENS Paris) and R. Schoelkopf (Yale). The workshop was very successful, and we hope that the reader will be satisfied with the scientific level of the present book. Before addressing scientific issues I find it suitable to address several non-scientific ones. The workshop was attended by researchers from many countries. Most of them perform their activities in academic institutions, where one usually finds the necessary isolation from the problems and sores of the modem world. However, there was a large group of participants for which such isolation was far from perfect. War, hatred, and violence rage just several miles away of their campuses and laboratories, poisoning everyday life in the land of Israel.
Download or read book Advances in Solid State Physics 46 written by Rolf Haug and published by Springer Science & Business Media. This book was released on 2007-12-05 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents written versions of selected invited lectures from the spring meeting of the Arbeitskreis Festkörperphysik of the Deutsche Physikalische Gesellschaft which was held from 27 to 31 March 2006 in Dresden, Germany. Many topical talks given at the numerous symposia are included. Most of these were organized collaboratively by several of the divisions of the Arbeitskreis. The book presents, to some extent, the status of the field of solid-state physics in 2006 not only in Germany but also internationally.
Download or read book Quantum Phenomena in Mesoscopic Systems written by B. Altshuler and published by IOS Press. This book was released on 2004-01-28 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a snapshot of the vision shared by outstanding scientists on the key theoretical and experimental issues in Mesoscopic Physics. Quantum properties of electrons in solid state devices and transport in semiconducting and superconducting low-dimensional systems, are discussed, as well as the basis of quantum computing (entanglement, noise decoherence and read-out). Each chapter collects the material presented at a Varenna School course of last year, by leading experts in the field. The reader gets a flavor, how theorists and experimentalists are paving the way to the physical realization of solid state qubits, the basic units of the new logic and memory elements for quantum processing. He will be surprised in finding that mesoscopic solid state devices, which were invented just yesterday ( think of the Single Electron Transistor, or the Cooper Pair Box) are currently used as charge-sensing applications in the equipment of frontier research laboratories. These devices contribute as probing systems to produce evidence on still unsettled questions in topics like the metal-insulator transition in disordered two dimensional systems, quantum Hall conductance in heterostructures, or Kondo conductance in quantum dots.
Download or read book Solid state Qubits with Current controlled Coupling written by Travis James Hime and published by . This book was released on 2007 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Information written by Dagmar Bruss and published by John Wiley & Sons. This book was released on 2019-01-30 with total page 909 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive textbook on the rapidly advancing field introduces readers to the fundamental concepts of information theory and quantum entanglement, taking into account the current state of research and development. It thus covers all current concepts in quantum computing, both theoretical and experimental, before moving on to the latest implementations of quantum computing and communication protocols. It contains problems and exercises and is therefore ideally suited for students and lecturers in physics and informatics, as well as experimental and theoretical physicists in academia and industry who work in the field of quantum information processing. The second edition incorporates important recent developments such as quantum metrology, quantum correlations beyond entanglement, and advances in quantum computing with solid state devices.
Download or read book Electron Correlation in New Materials and Nanosystems written by Kurt Scharnberg and published by Springer Science & Business Media. This book was released on 2007-05-24 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: The articles collected in this book cover a wide range of materials with extraordinary superconducting and magnetic properties. For many of the materials studied, strong electronic correlations provide a link between these two phenomena which were long thought to be highly antagonistic. The book reports both the progress in our understanding of fundamental physical processes and the advances made towards the development of devices.
Download or read book Quantum Information and Computation for Chemistry Volume 154 written by Sabre Kais and published by John Wiley & Sons. This book was released on 2014-01-31 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examines the intersection of quantum information and chemical physics The Advances in Chemical Physics series is dedicated to reviewing new and emerging topics as well as the latest developments in traditional areas of study in the field of chemical physics. Each volume features detailed comprehensive analyses coupled with individual points of view that integrate the many disciplines of science that are needed for a full understanding of chemical physics. This volume of the series explores the latest research findings, applications, and new research paths from the quantum information science community. It examines topics in quantum computation and quantum information that are related to or intersect with key topics in chemical physics. The reviews address both what chemistry can contribute to quantum information and what quantum information can contribute to the study of chemical systems, surveying both theoretical and experimental quantum information research within the field of chemical physics. With contributions from an international team of leading experts, Volume 154 offers seventeen detailed reviews, including: Introduction to quantum information and computation for chemistry Quantum computing approach to non-relativistic and relativistic molecular energy calculations Quantum algorithms for continuous problems and their applications Photonic toolbox for quantum simulation Vibrational energy and information transfer through molecular chains Tensor networks for entanglement evolution Reviews published in Advances in Chemical Physics are typically longer than those published in journals, providing the space needed for readers to fully grasp the topic: the fundamentals as well as the latest discoveries, applications, and emerging avenues of research. Extensive cross-referencing enables readers to explore the primary research studies underlying each topic.
Download or read book Quantum Information 2 Volume Set written by Dagmar Bruss and published by John Wiley & Sons. This book was released on 2019-06-10 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive textbook on the rapidly advancing field introduces readers to the fundamental concepts of information theory and quantum entanglement, taking into account the current state of research and development. It thus covers all current concepts in quantum computing, both theoretical and experimental, before moving on to the latest implementations of quantum computing and communication protocols. It contains problems and exercises and is therefore ideally suited for students and lecturers in physics and informatics, as well as experimental and theoretical physicists in academia and industry who work in the field of quantum information processing. The second edition incorporates important recent developments such as quantum metrology, quantum correlations beyond entanglement, and advances in quantum computing with solid state devices.
Download or read book Towards Solid State Quantum Repeaters written by Kristiaan De Greve and published by Springer. This book was released on 2013-05-04 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Towards Solid-State Quantum Repeaters: Ultrafast, Coherent Optical Control and Spin-Photon Entanglement in Charged InAs Quantum Dots summarizes several state-of-the-art coherent spin manipulation experiments in III-V quantum dots. Both high-fidelity optical manipulation, decoherence due to nuclear spins and the spin coherence extraction are discussed, as is the generation of entanglement between a single spin qubit and a photonic qubit. The experimental results are analyzed and discussed in the context of future quantum technologies, such as quantum repeaters. Single spins in optically active semiconductor host materials have emerged as leading candidates for quantum information processing (QIP). The quantum nature of the spin allows for encoding of stationary, memory quantum bits (qubits), and the relatively weak interaction with the host material preserves the spin coherence. On the other hand, optically active host materials permit direct interfacing with light, which can be used for all-optical qubit manipulation, and for efficiently mapping matter qubits into photonic qubits that are suited for long-distance quantum communication.
Download or read book Decoherence in Semiconductor Solid state Quantum Computers written by Diego Castelo Branco Valente and published by . This book was released on 2009 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation we discuss decoherence in charge qubits formed by multiple lateral quantum dots in the framework of the spin-boson model and the Born-Markov approximation. We consider the intrinsic decoherence caused by the coupling to bulk phonon modes and electromagnetic environmental fluctuations. In the case of decoherence caused by phonon coupling, two distinct quantum dot configurations are studied and proposed as setups that mitigate its nocive effects : (i) Three quantum dots in a ring geometry with one excess electron in total and (ii) arrays of quantum dots where the computational basis states form multipole charge configurations. For the three-dot qubit, we demonstrate the possibility of performing one- and two-qubit operations by solely tuning gate voltages. Compared to a previous proposal involving a linear three-dot spin qubit, the three-dot charge qubit allows for less overhead on two-qubit operations. For small interdot tunnel amplitudes, the three-dot qubits have Q factors much higher than those obtained for double-dot systems. The high-multipole dot configurations also show a substantial decrease in decoherence at low operation frequencies when compared to the double-dot qubit. We also discuss decoherence due to electromagnetic fluctuations in charge qubits formed by two lateral quantum dots. We use effective circuit models to evaluate correlations of voltage fluctuations in the qubit setup. These correlations allows us to estimate energy (T1) and phase (T2) relaxation times of the the qubit system. We also discuss the dependence the quality factor Q shows with respect to parameters of the setup, such as temperature and capacitive coupling between the electrodes.
