1,720,971 research outputs found
Fast Prediction of Full Quantum Dynamics with Deep Recurrent Neural Networks
No full textGemstone Team ASQNumerical simulations of interacting quantum systems are computationally very intensive, typically requiring resources that scale exponentially in the number of particles. A plausible approach to overcoming this unfavorable simulation time is to train deep neural networks over short timescales and use them to infer dynamics over much longer timescales. We demonstrate that such a speedup is possible using deep recurrent neural networks, including LSTM and Transformer-based networks, by predicting the quantum dynamics of multiple ’classic’ systems - the Ising, Heisenberg, and Hubbard models, with up to 9 spins, at most. We observe up to 3 orders of magnitude of data generation speedup for systems that can still be simulated with full system evolution. We observe this same performance - O(0.1) seconds - to generate data samples that cannot be generated with the resources we have available to use. Unique to our work, we predict the full wavefunction dynamics of the systems, which can then be used to calculate the
evolution of measurable and theoretical observables over time. We present sample predictions for our models and compare the efficacy of the different approaches with varying context-length
for prediction, spin count, and Hamiltonian parameters (mixing, interaction strength, etc.), at
best accurately predicting (< 10−6 mean square error - MSE) up to 90% of a single period with
10% of a period for context. We probe a number of frustrations, including square and triangular
interaction lattices, more complex next-nearest neighbor interactions, etc. to understand what
currently limits strong machine learning - ML - results in this space. Our results indicate that
the primary inhibitor to fast prediction at scale is the system scale, not the complexity of the dynamics. We anticipate that our work will provide insights towards extending the coherence time of quantum systems such as qubits and spins by determining the issues that stand in the way of network training and prediction on realistic Hamiltonians. We further believe that this work has immediate application in the simulation of large-scale neutral atom arrays, like Yt-171, under so-called Lieb-Robinson bounds
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
On-chip quantum and nonlinear optics: from squeezing to spectroscopy
No full textQuantum and nonlinear optics has garnered a lot of interest in the last few decades due to its applications in a plethora of fields such as sensing, spectroscopy, frequency metrology and quantum information processing. Optical microresonators have compactified the realization of several nonlinear phenomena since their inception, besides enabling fundamentally new paradigms in light-matter interaction. Planar microcavities such as ring resonators are particularly interesting for their ease of fabrication in a massively parallel fashion and their small mode volumes. Additionally, advances in fabrication techniques have enabled ultra-low losses and ultra-high quality factors in these planar CMOS compatible materials such as silica and silicon nitride.
In this dissertation, we harness the ultra-low loss of silicon nitride microrings along with its high third-order Kerr nonlinearity for two applications previously unexplored in this platform: bright squeezed light generation and dual comb spectroscopy. We begin by examining the background in each of these fields before detailing our approach to realizing a compact, robust and scalable alternative to the existing state-of-the-art.
The first part of this dissertation investigates squeezed light, a quantum state of light that is promising for quantum enhanced sensing and quantum computation or communication in the continuous variable regime. Nearly all previous chip-based sources of squeezing have been rather large (of the order of many wavelengths in height and width), and work based on the second-order nonlinearity, which is found only in restrictive crystals lacking inversion symmetry. Here we report the first realization of squeezing using an integrated parametric oscillator above threshold based on the ubiquitous third-order nonlinearity. The on-chip microrings enable the generation of broadband continuous wave squeezing in contrast to the narrowband squeezing produced by their macroscopic counterparts, and this broad bandwidth is essential for high-bit-rate quantum communications. Furthermore, we show continuous electrical tuning of the degree of squeezing using integrated platinum microheaters incorporated above coupled microring resonators. We conclude our exploration of quantum photonics in silicon nitride with a path towards deterministic entanglement generation.
In the second part of this dissertation, we look into a classical application of the same platform: dual comb spectroscopy (DCS). This technique builds upon an actively pursued aspect of silicon nitride rings -- that of frequency comb generation. Again, using the third-order Kerr nonlinearity, a series of narrow, equidistant lines can be generated in the frequency domain, to form a spectrum that is called a frequency comb. Two such combs with slightly different line spacings can be used for dual comb spectroscopy, which is an emerging technique for fast acquisition of broadband optical spectra. Since DCS does not involve any moving mechanical parts that are used in conventional spectrometers, it is much more robust. We generate, for the first time, two frequency combs on the same chip using a single laser, and use it for broadband spectroscopy of dichloromethane.
We demonstrate simultaneous soliton modelocking of both combs and observe long mutual coherence times of 100 \textmu s. Our results pave the way for an on-chip, fully integrated dual comb spectrometer
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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