Download or read book Interaction Between Quantum Dots and Superconducting Microwave Resonators written by Tobias Sebastian Frey and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Detection and Interaction of Single Quantum States written by Sishen Xie and published by Springer Nature. This book was released on 2023-07-25 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the findings and achievements in the major research plan “Detection and Interaction of Single Quantum States” funded by the National Natural Science Foundation of China (NSFC). The 8-year plan started in 2011 and consisted of 107 projects conducted by Chinese universities and research institutes. The book covers the plan's research background, achievements, and follow-up prospects. The plan aimed to tackle one of the major challenges for researchers worldwide—to establish precise detection and control of single quantum states in time, space, energy, and momentum. The plan integrated precise detection means with the ultrahigh resolution of time, space, and energy, under extreme conditions such as ultrahigh vacuum, ultralow temperature, high magnetic field, and ultrahigh pressure, using interdisciplinary research methods in physics, chemistry, informatics, and materials science. The book focuses on the exploration of new phenomena, theories, and concepts of single quantum states, describes new techniques and methods of single quantum states, and presents the purification and construction of single-quantum-state systems. It is a concise and valuable source of information for researchers in quantum science and graduate students interested in the research field.
Download or read book Coupling Between Quantum Dot Qubits and a Superconducting Microwave Resonator written by Cameron Eric King and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum computing has the potential to achieve better scaling for factoring large numbers, simulating quantum behavior of molecules, and sampling random number distributions. Quantum dot qubits in silicon show strong promise as a qubit platform due to the long decoherence times measured as well as the possibility of leveraging techniques from classical processor fabrication towards scaling to large qubit systems. We examine coupling quantum dot qubits to a superconducting coplanar waveguide, which functions as a single-photon resonator, and this system enables coherent communications between qubit systems. We are concerned with both the hardware and low-level software of quantum computation. We examine geometric modifications to the heterostructure and the electrode geometry to boost the capacitive coupling between a triple dot system and a resonator. We find decreasing the vertical separation between the electrode connected to the resonator and the dots has a positive impact on the coupling strength. Continuing hardware simulations, we consider the issue of low device yield in Si-MOS devices, where despite large singlet-triplet splittings, there was no evidence of Pauli spin blockade. We attributed this to impurities within the oxide and performed a series of simulations that allowed us to determine the required impurity density to lift spin blockade, and found this density consistent with the device yield. Switching to considering different qubit encodings, we compared and contrasted the behavior of three qubits that are resonantly coupled to a superconducting resonator. The three encodings were the charge dipole (CD) qubit, the charge quadrupole (CQ) qubit, and the quantum dot hybrid qubit (QDHQ). In terms of entangling a one photon state with a qubit state, the CD qubit and the CQ qubit behaved similarly, however the CQ qubit does allow arbitrary single qubit gates while being protected from quasistatic charge noise. The QDHQ exhibited better performance (measured by infidelity) when operated at a second-order-sweet spot than both other encodings in the typical charge noise regime. Furthermore, the quantum dot hybrid qubit enables multiple operating points, offering greater tuning flexibility when considering implementation in actual devices.
Download or read book Quantum Dot Optoelectronic Devices written by Peng Yu and published by Springer Nature. This book was released on 2020-04-16 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book captures cutting-edge research in semiconductor quantum dot devices, discussing preparation methods and properties, and providing a comprehensive overview of their optoelectronic applications. Quantum dots (QDs), with particle sizes in the nanometer range, have unique electronic and optical properties. They have the potential to open an avenue for next-generation optoelectronic methods and devices, such as lasers, biomarker assays, field effect transistors, LEDs, photodetectors, and solar concentrators. By bringing together leaders in the various application areas, this book is both a comprehensive introduction to different kinds of QDs with unique physical properties as well as their preparation routes, and a platform for knowledge sharing and dissemination of the latest advances in a novel area of nanotechnology.
Download or read book Lateral Quantum Dots for Quantum Information Processing written by Matthew Gregory House and published by . This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The possibility of building a computer that takes advantage of the most subtle nature of quantum physics has been driving a lot of research in atomic and solid state physics for some time. It is still not clear what physical system or systems can be used for this purpose. One possibility that has been attracting significant attention from researchers is to use the spin state of an electron confined in a semiconductor quantum dot. The electron spin is magnetic in nature, so it naturally is well isolated from electrical fluctuations that can a loss of quantum coherence. It can also be manipulated electrically, by taking advantage of the exchange interaction. In this work we describe several experiments we have done to study the electron spin properties of lateral quantum dots. We have developed lateral quantum dot devices based on the silicon metal-oxide-semiconductor transistor, and studied the physics of electrons confined in these quantum dots. We measured the electron spin excited state lifetime, which was found to be as long as 30 ms at the lowest magnetic fields that we could measure. We fabricated and characterized a silicon double quantum dot. Using this double quantum dot design, we fabricated devices which combined a silicon double quantum dot with a superconducting microwave resonator. The microwave resonator was found to be sensitive to two-dimensional electrons in the transistor channel, which we measured and characterized. We developed a new method for extracting information from random telegraph signals, which are produced when we observe thermal fluctuations of electrons in quantum dots. The new statistical method, based on the hidden Markov model, allows us to detect spin-dependent effects in such fluctuations even though we are not able to directly observe the electron spin. We use this analysis technique on data from two experiments involving gallium arsenide quantum dots and use it to measure spin-dependent tunneling rates. Our results advance the understanding of electron spin physics in lateral quantum dots, in silicon and in gallium arsenide.
Download or read book Open Quantum Dots Modeled with Microwave Cavities written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, open microwave resonators have been investigated as a model system of a quantum dot. Since quantum dots are micrometer-sized, measurements in quantum dots are still very difficult except for transport measurement, but relatively simple in a microwave resonator. We fabricated a flat resonator and a resonator with soft-wall potential so that the shape corresponded to a quantum dot which has been investigated in the laboratory of J.P. Bird. For a flat resonator, i.e. a resonator with a hard-wall potential, periodically occurring scarred wave function families are analyzed, and the associated orbits are identified. For complicated wave function families, we use a Fourier spectroscopy. Influence of an absorber center is investigated using Fourier transform of transmission between the input and output leads. The Fourier map is analyzed to identify scar families. The calculated orbits lengths and the experimentally obtained values show very good agreement. By varying the height of the resonator, potentials can be simulated, using the correspondence between quantum mechanics and electrodynamics. Using this relation, a resonator with soft-wall potential was fabricated. The shape of the potential corresponds to the above mentioned quantum dot. The measured eigenfrequencies for the periodic bouncing-ball scar families agree very well with the theoretical values from a WKB approximation . The wave function family of an X-like cross bouncing ball is used to obtain evidence of dynamical tunneling. By phase difference analysis and transport behavior, the presence of dynamical tunneling is proven. In the last part of this work, the statistical properties of the wave functions of an asymmetric open flat resonator are discussed. Opening to the outside world of billiard makes the wave function complex, since there is transport. This cross-over regime, from real to imaginary of wave functions is investigated opening of the billiard by frequency increasing. The phase rigid.
Download or read book Quantum circuits based on artificial magnetic molecules written by Ignacio Gimeno Alonso and published by Prensas de la Universidad de Zaragoza. This book was released on 2023-03-27 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autor: Ignacio Gimeno Alonso Colección: Colección Estudios de Física. CEF-158 Richard Feynman was the first to propose the idea of applying the laws of quantum physics to perform computational tasks in 1982. David Deutsch then generalised the notion of a Turing machine to the quantum realm, in-troducing the notion of a universal quantum computer. In this system, the bit (the classical unit of information) is replaced by the quantum bit or qubit. The quantum superposition principle allows the qubit to be in any superposition state a |0⟩ + b |1⟩, instead of being in just one of the two states 0 or 1 as a classical bit. This "quantum parallelism" is the key property of a quantum computer, which provides access to an exponentially larger set of states to process information. It makes it possible to simulate quantum systems that classical computers cannot afford due to their size. It could also solve new tasks, as creating true random numbers, and improve others such as the database searching, and prime number factorisation.
Download or read book Tailored Electron phonon Interactions in Semiconductor Double Quantum Dots written by Thomas Richard Hartke and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis demonstrates the construction of a double quantum dot (DQD) in an Indium Arsenide (InAs) nanowire that is mechanically suspended in vacuum between metal contacts and capacitively coupled to a superconducting microwave resonator. This mechanical suspension scheme places the DQD at the center of an effective 380 nm long phonon cavity created by the contacts supporting the ends of the suspended nanowire. Because electron-phonon coupling mechanisms lead to electron transport through the DQD, measurements of current can be used as a probe of the phonon density of states in the nanostructure. Current measurements reveal strong signatures of electron-phonon coupling at energies corresponding to the guitar string vibrational modes of the suspended nanowire. In addition, photon emission has recently been observed in InAs nanowire DQDs coupled to superconducting cavities. However, it has been proposed that a phonon must simultaneously be emitted with each photon to ensure energy conservation. Therefore the photon emission rate should be enhanced when the emitted phonons couple strongly to electrons in the DQD. We quantitatively confirm this hypothesis by independently measuring both the photon emission into the cavity and the electron-phonon coupling strength as a function of the DQD energy splitting.
Download or read book Quantum Dots written by Lucjan Jacak and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present an overview of the theoretical background and experimental re sults in the rapidly developing field of semiconductor quantum dots - systems 8 6 of dimensions as small as 10- -10- m (quasi-zero-dimensional) that contain a small and controllable number (1-1000) of electrons. The electronic structure of quantum dots, including the energy quan tization of the single-particle states (due to spatial confinement) and the evolution of these (Fock-Darwin) states in an increasing external magnetic field, is described. The properties of many-electron systems confined in a dot are also studied. This includes the separation of the center-of-mass mo tion for the parabolic confining potential (and hence the insensitivity of the transitions under far infrared radiation to the Coulomb interactions and the number of particles - the generalized Kohn theorem) and the effects due to Coulomb interactions (formation of the incompressible magic states at high magnetic fields and their relation to composite jermions), and finally the spin-orbit interactions. In addition, the excitonic properties of quantum dots are discussed, including the energy levels and the spectral function of a single exciton, the relaxation of confined carriers, the metastable states and their effect on the photoluminescence spectrum, the interaction of an exciton with carriers, and exciton condensation. The theoretical part of this work, which is based largely on original re sults obtained by the authors, has been supplemented with descriptions of various methods of creating quantum-dot structures.
Download or read book Quantum Dots written by Peter A. Ling and published by Nova Publishers. This book was released on 2005 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atoms are quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology, they are called quantum bits or qubits. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10-9 meter or a millionth of a millimetre. The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. Other applications of quantum dots include nanomachines, neural networks, and high-density memory or storage media. Research is being carried out on nano-crystals, self-assembled dots, and gated structures. This book presents leading-edge research from around the world.
Download or read book High Resolution Optical Spectroscopy of Single Quantum Dots and Cavity QED Effects and Lasing in Quantum Dot Microdisk Resonator Structures written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project was initiated to study quantum electrodynamic effects (QED) on the interaction between quantum dots and the electromagnetic field. Investigations of quantized matter-field interactions involving self-assembled quantum dots required an advance in the understanding of the electronic structure and optical properties of strained quantum dots. Consequently much of the research carried out under this grant centered on clarifying these issues. Problems investigated included: optimization of the growth process by which the quantum dots were formed; physical characterization of the microstructure of the quantum dots so as to identify their symmetries and to enable the creation of appropriate electronic structure models; the use of these results to calculate electronic structure; and spectroscopic tests of the models.
Download or read book Coupling Quantum Dot Circuits to Microwave Cavities written by Matthieu Delbecq and published by . This book was released on 2012 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dot circuits (qd) in a circuit cavity quantum electrodynamics (cqed) architecture. the interest of such hybrid systems lies in the light-matter interaction that occurs between the cavity microwave photons and the electrons of the qd. in this thesis work, carbon nanotubes have been chosen as the material for the qds. indeed, it is possible to observe various electronic transport regimes in such systems (fabry-perot, coulomb blockade and kondo). their versatility is also a keypoint as it is possible to contact them with various type of metal electrodes (normal, superconductor, ferromagnetic metal). the experimental realization of such devices has the project of this thesis was to experimentally realize the implementation of shown an electron-photon coupling of the order of 100mhz, comparable to standard cqed couplings. this coupling is tunable by purely electric control. finally, wehave demonstrated the distant interaction between two qds, separated by 80μm, via the microwave cavity photons. these results shows that these devices can be used for manipulating the quantum information as well as for simulate on-chip condensed matter situations. we have therefore been able to measure the quantum capacitance of the qds, and in particular in the kondo regime. we have also simulated the electron-phonon polaronic shift in the case of the distant interaction between the two qds.
Download or read book Circuit Quantum Electrodynamics with Si SiGe Quantum Dots written by Nathan Holman and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses the theoretical and experimental development of a "hybrid" circuit quantum electrodynamics (cQED) architecture to interface electrons in Si/SiGe heterostructures to microwave photons trapped in superconducting resonators. To utilize cQED for long range interactions, one must reach the strong coupling regime between light and charge. Although this regime was not reached with certainty in this work, significant progress was made in understanding and engineering away the limiting factors of each component of the physical system: photon leakage, charge noise, and small electric dipole coupling strengths. Photon loss is mitigated using a novel, compact wiring scheme to bias the quantum dots but strongly mismatch the photon from the environmental impedance. Charge noise was reduced by development of an ultra thin, low noise SiO2 gate dielectric aiding observation of coherent valley-orbit qubit Landau-Zener-Stuckelberg oscillations in a single electron double quantum dot. Lastly, development of high kinetic inductance materials and an understanding of the effects of valley states on the dipolar coupling strength were developed.
Download or read book Optimization of a Microwave Resonator Cavity to Perform Electron Spin Resonance Measurements on Quantum Dots written by Anat Burger and published by . This book was released on 2006 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis attempts to improve on an ongoing experiment of detecting electron spin resonance (ESR) on AlGaAs/GaAs lateral quantum dots. The experiment is performed in a 2.5 Tesla magnetic field at temperatures around 100mK. A resonator cavity is used to expose the quantum dot to a perturbational microwave magnetic field pulse that induces electron spin flip transitions. The statistics for measuring the probabilities of these transitions can be improved by increasing the strength and/or the duration of the pulsed magnetic field. The drawback is that both of these improvements lead to thermal heating which diminishes the quantum nature of the dot. I used electromagnetic field calculations and simulation software to explore different resonant modes, geometries, materials, and methods of excitation and optimize the design of potential new cavities. Two cavities were built specifically to test the TM010 and TE011 cylindrical modes. Although they did not perform as well as was theoretically expected, these cavities provide a better magnetic field magnitude per heating power than the current cavity.
Download or read book Photonics Volume 1 written by David L. Andrews and published by John Wiley & Sons. This book was released on 2015-01-16 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonics. This volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Polarization States; Quantum Electrodynamics; Quantum Information and Computing; Quantum Optics; Resonance Energy Transfer; Surface Optics; Ultrafast Pulse Phenomena. Comprehensive and accessible coverage of the whole of modern photonics Emphasizes processes and applications that specifically exploit photon attributes of light Deals with the rapidly advancing area of modern optics Chapters are written by top scientists in their field Written for the graduate level student in physical sciences; Industrial and academic researchers in photonics, graduate students in the area; College lecturers, educators, policymakers, consultants, Scientific and technical libraries, government laboratories, NIH.
Download or read book Spins in Optically Active Quantum Dots written by Oliver Gywat and published by John Wiley & Sons. This book was released on 2010-02-01 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling a gap in the literature, this up-to-date introduction to the field provides an overview of current experimental techniques, basic theoretical concepts, and sample fabrication methods. Following an introduction, this monograph deals with optically active quantum dots and their integration into electro-optical devices, before looking at the theory of quantum confined states and quantum dots interacting with the radiation field. Final chapters cover spin-spin interaction in quantum dots as well as spin and charge states, showing how to use single spins for break-through quantum computation. A conclusion and outlook round off the volume. The result is a primer providing the essential basic knowledge necessary for young researchers entering the field, as well as semiconductor and theoretical physicists, PhD students in physics and material sciences, electrical engineers and materials scientists.
Download or read book Journal of the Physical Society of Japan written by and published by . This book was released on 2014 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
