244 research outputs found
Roadmap on structured waves
Structured waves are ubiquitous for all areas of wave physics, both classical
and quantum, where the wavefields are inhomogeneous and cannot be approximated
by a single plane wave. Even the interference of two plane waves, or a single
inhomogeneous (evanescent) wave, provides a number of nontrivial phenomena and
additional functionalities as compared to a single plane wave. Complex
wavefields with inhomogeneities in the amplitude, phase, and polarization,
including topological structures and singularities, underpin modern nanooptics
and photonics, yet they are equally important, e.g., for quantum matter waves,
acoustics, water waves, etc. Structured waves are crucial in optical and
electron microscopy, wave propagation and scattering, imaging, communications,
quantum optics, topological and non-Hermitian wave systems, quantum
condensed-matter systems, optomechanics, plasmonics and metamaterials, optical
and acoustic manipulation, and so forth. This Roadmap is written collectively
by prominent researchers and aims to survey the role of structured waves in
various areas of wave physics. Providing background, current research, and
anticipating future developments, it will be of interest to a wide
cross-disciplinary audience.Comment: 110 pages, many figure
Constructing networks of quantum channels for state preparation
Entangled possibly mixed states are an essential resource for quantum computation, communication, metrology, and the simulation of many-body systems. It is important to develop and improve preparation protocols for such states.
One possible way to prepare states of interest is to design an open system that evolves only towards the desired states. A Markovian evolution of a quantum system can be generally described by a Lindbladian. Tensor networks provide a framework to construct physically relevant entangled states. In particular, matrix product density operators (MPDOs) form an important variational class of states. MPDOs generalize matrix product states to mixed states, can represent thermal states of local one-dimensional Hamiltonians at sufficiently large temperatures, describe systems that satisfy the area law of entanglement, and form the basis of powerful numerical methods. In this work we develop an algorithm that determines for a given linear subspace of MPDOs whether this subspace can be the stable space of some frustration free k-local Lindbladian and, if so, outputs an appropriate Lindbladian.
We proceed by using machine learning with networks of quantum channels, also known as quantum neural networks (QNNs), to train denoising post-processing devices for quantum sources. First, we show that QNNs can be trained on imperfect devices even when part of the training data is corrupted. Second, we show that QNNs can be trained to extrapolate quantum states to, e.g., lower temperatures. Third, we show how to denoise quantum states in an unsupervised manner. We develop a novel quantum autoencoder that successfully denoises Greenberger-Horne-Zeilinger, W, Dicke, and cluster states subject to spin-flip, dephasing errors, and random unitary noise.
Finally, we develop recurrent QNNs (RQNNs) for denoising that requires memory, such as combating drifts. RQNNs can be thought of as matrix product quantum channels with a quantum algorithm for training and are closely related to MPDOs.
The proposed preparation and denoising protocols can be beneficial for various emergent quantum technologies and are within reach of present-day experiments
High dimensional autocompensating quantum cryptography in optical fibers implemented with discrete and integrated photonic devices
O obxectivo global desta tese é contribuir ao deseño de novos sistemas de
criptografía cuántica e ao desenvolvemento de dispositivos fotónicos discretos e integrados que implementen
operacións específicas para implementalos usando multiplexación espacial. Deste xeito, na tese propoñense novos
metodos de encriptación cuántica autocompensada, que fan uso dos modos espaciais propagados por diversas
fibras ópticas (fibras de poucos modos e multinúcleo) para conseguir transmitir información en alta dimensión,
correxindo tódalas fluctuacións que estes sofren ao longo da transmisión pola fibra. Ao mesmo tempo, deseñanse
os distintos dispositivos fotónicos necesarios para implementar ditos métodos, baseados tanto en elementos
ópticos discretos como en dispositivos integrados. En particular, na tese presentanse novos dispositivos para xerar
estados cuánticos útiles en criptografía (baseados en estados vórtice), así como proxectores cuánticos capaces de
medir ditos estados. Ademáis, na tese demóstrase a viabilidade de fabricar ditos dispositivos de xeito integrado por
medio de intercambio iónico en vidrio
Understanding Quantum Technologies 2022
Understanding Quantum Technologies 2022 is a creative-commons ebook that
provides a unique 360 degrees overview of quantum technologies from science and
technology to geopolitical and societal issues. It covers quantum physics
history, quantum physics 101, gate-based quantum computing, quantum computing
engineering (including quantum error corrections and quantum computing
energetics), quantum computing hardware (all qubit types, including quantum
annealing and quantum simulation paradigms, history, science, research,
implementation and vendors), quantum enabling technologies (cryogenics, control
electronics, photonics, components fabs, raw materials), quantum computing
algorithms, software development tools and use cases, unconventional computing
(potential alternatives to quantum and classical computing), quantum
telecommunications and cryptography, quantum sensing, quantum technologies
around the world, quantum technologies societal impact and even quantum fake
sciences. The main audience are computer science engineers, developers and IT
specialists as well as quantum scientists and students who want to acquire a
global view of how quantum technologies work, and particularly quantum
computing. This version is an extensive update to the 2021 edition published in
October 2021.Comment: 1132 pages, 920 figures, Letter forma
Faculty Publications and Creative Works 2004
Faculty Publications & Creative Works is an annual compendium of scholarly and creative activities of University of New Mexico faculty during the noted calendar year. Published by the Office of the Vice President for Research and Economic Development, it serves to illustrate the robust and active intellectual pursuits conducted by the faculty in support of teaching and research at UNM
A Brief Review on Mathematical Tools Applicable to Quantum Computing for Modelling and Optimization Problems in Engineering
Since its emergence, quantum computing has enabled a wide spectrum of new possibilities and advantages, including its efficiency in accelerating computational processes exponentially. This has directed much research towards completely novel ways of solving a wide variety of engineering problems, especially through describing quantum versions of many mathematical tools such as Fourier and Laplace transforms, differential equations, systems of linear equations, and optimization techniques, among others. Exploration and development in this direction will revolutionize the world of engineering. In this manuscript, we review the state of the art of these emerging techniques from the perspective of quantum computer development and performance optimization, with a focus on the most common mathematical tools that support engineering applications. This review focuses on the application of these mathematical tools to quantum computer development and performance improvement/optimization. It also identifies the challenges and limitations related to the exploitation of quantum computing and outlines the main opportunities for future contributions. This review aims at offering a valuable reference for researchers in fields of engineering that are likely to turn to quantum computing for solutions. Doi: 10.28991/ESJ-2023-07-01-020 Full Text: PD
Roadmap of optical communications
© 2016 IOP Publishing Ltd. Lightwave communications is a necessity for the information age. Optical links provide enormous bandwidth, and the optical fiber is the only medium that can meet the modern society's needs for transporting massive amounts of data over long distances. Applications range from global high-capacity networks, which constitute the backbone of the internet, to the massively parallel interconnects that provide data connectivity inside datacenters and supercomputers. Optical communications is a diverse and rapidly changing field, where experts in photonics, communications, electronics, and signal processing work side by side to meet the ever-increasing demands for higher capacity, lower cost, and lower energy consumption, while adapting the system design to novel services and technologies. Due to the interdisciplinary nature of this rich research field, Journal of Optics has invited 16 researchers, each a world-leading expert in their respective subfields, to contribute a section to this invited review article, summarizing their views on state-of-the-art and future developments in optical communications
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