Hasil untuk "General Works"

Philippe Faist

The minimum amount of thermodynamic work required in order to implement a quantum computation or a quantum state transformation can be quantified using frameworks based on the resource theory of thermodynamics, deeply rooted in the works of Landauer and Bennett. For instance, the work we need to invest in order to implement $n$ independent and identically distributed (i.i.d.) copies of a quantum channel is quantified by the thermodynamic capacity of the channel when we require the implementation's accuracy to be guaranteed in diamond norm over the $n$-system input. Recent work showed that work extraction can be implemented universally, meaning the same implementation works for a large class of input states, while achieving a variable work cost that is optimal for each individual i.i.d. input state. Here, we revisit some techniques leading to derivation of the thermodynamic capacity, and leverage them to construct a thermodynamic implementation of $n$ i.i.d. copies of any time-covariant quantum channel, up to some process decoherence that is necessary because the implementation reveals the amount of consumed work. The protocol uses so-called thermal operations and achieves the optimal per-input work cost for any i.i.d. input state; it relies on the conditional erasure protocol in our earlier work, adjusted to yield variable work. We discuss the effect of the work-cost decoherence. While it can significantly corrupt the correlations between the output state and any reference system, we show that for any time-covariant i.i.d. input state, the state on the output system faithfully reproduces that of the desired process to be implemented. As an immediate consequence of our results, we recover recent results for optimal work extraction from i.i.d. states up to the error scaling and implementation specifics, and propose an optimal preparation protocol for time-covariant i.i.d. states.

Yingqian Huang, Yanfeng Jiang, Xinran Hou

Alleviating rural poverty plays a critical role in achieving comprehensive rural revitalization. This study selects typical villages in karst rocky desertification poverty-stricken mountainous areas as the research objects and applies fuzzy-set qualitative comparative analysis (fsQCA) and necessary condition analysis (NCA). Using an element–structure–function framework, this paper explores the driving mechanism of the multi-factor linkage of rural regional systems and the revitalization of poverty-stricken villages. The results show that single antecedent conditions are not necessary conditions for the rural revitalization of poverty-stricken villages. There are seven distinct pathways to achieve the revitalization of poverty-stricken villages, which are categorized into function–structure driven types, function–element driven types, and function–structure–element driven types. Each type has different configurations of influencing factors. This study uncovers the complex interaction mechanism among multiple factors behind the rural revitalization of poverty-stricken villages from a systematic perspective, offering insights to guide targeted local policy development.

Michael J. Connolly

We develop a generalized projective gauge theory of gravity and spinorial matter, incorporating both non-metricity and torsion. The work is divided into three parts. Part I provides a thorough review of General Relativity, Metric-Affine gauge theory and Thomas-Whitehead (TW) Gravity. Part II constructs a gauge gravitational theory based on the Projective General Linear Group, wherein the newly found projective symmetric teleparallel (PST) connections are defined. Generalizing to non-inertial frames, and using nonlinear gauge symmetry realizations to implement local Lorentz symmetry, we construct a general geometric framework that unifies TW and Metric-Affine gravity with projectively invariant spacetime torsion. We introduce projective generalized Higgs fields and show how certain gauge choices reduce these to fundamental projective fields, and how they may be used to define fundamental geometric objects such as the projective 2-frame and spacetime connection. A Lovelock-inspired action is shown to support only curvature (metric) dynamics, implying a topologically constrained Schouten field via the Pontrjagin density. The projective Pontrjagin density is shown to contain a new topological invariant, not present in the literature. Part III formulates projective spinors by defining gamma matrices via the projective linear group metric, then employing nonlinear gauge symmetry realizations to ensure local Lorentz covariance. A general spinor metric introduces a complex phase of redundancy. Requiring a real, Hermitian action leads to a projective Einstein-Cartan-type theory. An induced chiral mass emerges without CP violation.

Ward Struyve

While Einstein was guided by the principle of general covariance in formulating general relativity, Kretschmann later argued that this principle lacks physical significance, since any space-time theory can be reformulated in a generally covariant form. This critique has prompted an ongoing debate over how to distinguish substantive general covariance from mere formal general covariance. Some proposals for defining substantive general covariance are based on the requirement that a theory be derivable from a diffeomorphism-invariant action. The present work aims to critically assess these proposals by examining canonical examples of Kretschmannian formulations of special relativistic theories. It will be shown that these formulations -- which seem merely formally generally covariant -- can always be derived from a diffeomorphism-invariant action. Although these actions involve auxiliary variables, these variables are trivial in the sense that they are either pure gauge or dynamically fixed by the other variables. Consequently, the theories described by these actions are arguably equivalent to the original Kretschmannian formulations. This stands in contrast to the actions proposed by Rosen and Sorkin, which include non-trivial auxiliary variables and hence seem to describe distinct physical theories. More recently, Freidel and Teh have suggested an additional criterion for substantial general covariance, namely that the action should also yield a non-trivial corner charge associated to diffeomorphism invariance. However, this too appears insufficient, since such actions can always be constructed.

Emanuel Moss, Elizabeth Watkins, Christopher Persaud et al.

Generative AI tools have become more prevalent in engineering workflows, particularly through chatbots and code assistants. As the perceived accuracy of these tools improves, questions arise about whether and how those who work in high-precision domains might maintain vigilance for errors, and what other aspects of using such tools might trouble their work. This paper analyzes interviews with hardware and software engineers, and their collaborators, who work in integrated circuit design to identify the role accuracy plays in their use of generative AI tools and what other forms of trouble they face in using such tools. The paper inventories these forms of trouble, which are then mapped to elements of generative AI systems, to conclude that controlling the context of interactions between engineers and the generative AI tools is one of the largest challenges they face. The paper concludes with recommendations for mitigating this form of trouble by increasing the ability to control context interactively.

Massimo Barbieri

Chitosan is a biopolymer synthesized by deacetylation of chitin, a polysaccharide that can be obtained from various renewable resources, mainly waste from marine food production [...]

Vesa Saarinen, Robin Rajamäki, Visa Koivunen

This paper develops a generative deep learning model for the synthesis of multiple-input multiple-output (MIMO) active sensing waveforms with desired properties, including constant modulus and a user-defined beampattern. The proposed approach is capable synthesizing unique phase codes of on-the-fly, which has the potential to reduce interference between co-existing active sensing systems and facilitate Low Probability of Intercept/Low Probability of Detection (LPI/LPD) radar operation. The paper extends our earlier work on synthesis of approximately orthogonal MIMO phase codes by introducing flexible control over the transmit beampatterns. The developed machine learning method employs a conditional Wasserstein Generative Adversarial Network (GAN) structure. The main benefits of the method are its ability to discover new waveforms on-demand (post training) and generate demanding beampatterns at lower computational complexity compared to structured optimization approaches.

Jason Saied, Jeffrey Marshall, Namit Anand et al.

We introduce state-of-the-art protocols to distill indistinguishable photons, reducing distinguishability error rates by a factor of $n$, while using a modest amount of resources scaling only linearly in $n$. Our resource requirements are both significantly lower and have fewer hardware requirements than previous works, making large-scale distillation experimentally feasible for the first time. This efficient reduction of distinguishability error rates has direct applications to fault-tolerant linear optical quantum computation, potentially leading to improved thresholds for photon loss errors and allowing smaller code distances, thus reducing overall resource costs. Our protocols are based on Fourier transforms on finite abelian groups, special cases of which include the discrete Fourier transform and Hadamard matrices. This general perspective allows us to unify previous results on distillation protocols and introduce a large family of efficient schemes. We utilize the rich mathematical structure of Fourier transforms, including symmetries and related suppression laws, to quantify the performance of these distillation protocols both analytically and numerically. Finally, our work resolves an open question concerning suppression laws for the $n$-photon discrete Fourier transform: the suppression laws are exactly characterized by the well-known Zero Transmission Law if and only if $n$ is a prime power.

Gonzalo Navarro, Francisco Olivares, Cristian Urbina

It was recently proved that any Straight-Line Program (SLP) generating a given string can be transformed in linear time into an equivalent balanced SLP of the same asymptotic size. We generalize this proof to a general class of grammars we call Generalized SLPs (GSLPs), which allow rules of the form $A \rightarrow x$ where $x$ is any Turing-complete representation (of size $|x|$) of a sequence of symbols (potentially much longer than $|x|$). We then specialize GSLPs to so-called Iterated SLPs (ISLPs), which allow rules of the form $A \rightarrow Π_{i=k_1}^{k_2} B_1^{i^{c_1}}\cdots B_t^{i^{c_t}}$ of size $2t+2$. We prove that ISLPs break, for some text families, the measure $δ$ based on substring complexity, a lower bound for most measures and compressors exploiting repetitiveness. Further, ISLPs can extract any substring of length $λ$, from the represented text $T[1.. n]$, in time $O(λ+ \log^2 n\log\log n)$. This is the first compressed representation for repetitive texts breaking $δ$ while, at the same time, supporting direct access to arbitrary text symbols in polylogarithmic time. We also show how to compute some substring queries, like range minima and next/previous smaller value, in time $O(\log^2 n \log\log n)$. Finally, we further specialize the grammars to Run-Length SLPs (RLSLPs), which restrict the rules allowed by ISLPs to the form $A \rightarrow B^t$. Apart from inheriting all the previous results with the term $\log^2 n \log\log n$ reduced to the near-optimal $\log n$, we show that RLSLPs can exploit balance to efficiently compute a wide class of substring queries we call ``composable'' -- i.e., $f(X \cdot Y)$ can be obtained from $f(X)$ and $f(Y)$...

Kason Ka Ching Cheung, Ho-Yin Chan, Sibel Erduran

Abstract News media plays a vital role in communicating scientific evidence to the public during the COVID-19 pandemic. Such communication is important for convincing the public to follow social distancing guidelines and to respond to health campaigns such as vaccination programmes. However, newspapers were criticised that they focus on the socio-political perspective of science, without explaining the nature of scientific works behind the government’s decisions. This paper examines the connections of the nature of science categories in the COVID-19 era by four local newspapers in the United Kingdom between November 2021 to February 2022. Nature of science refers to different aspects of how science works such as aims, values, methods and social institutions of science. Considering the news media may mediate public information and perception of scientific stories, it is relevant to ask how the various British newspapers covered aspects of science during the pandemic. In the period explored, Omicron variant was initially a variant of concern, and an increasing number of scientific evidence showed that the less severity of this variant might move the country from pandemic to endemic. We explored how news articles communicate public health information by addressing how science works during the period when Omicron variants surge. A novel discourse analysis approach, epistemic network analysis is used to characterise the frequency of connections of categories of the nature of science. The connection between political factors and the professional activities of scientists, as well as that with scientific practices are more apparent in left-populated and centralist outlets than in right-populated news outlets. Among four news outlets across the political spectrum, a left-populated newspaper, the Guardian, is not consistent in representing relations of different aspects of the nature of scientific works across different stages of the public health crisis. Inconsistency of addressing aspects of scientific works and a downplay of the cognitive-epistemic nature of scientific works likely lead to failure in trust and consumption of scientific knowledge by the public in the healthcare crisis.

Wengang Chen, Hongying He, Jianguo Liu et al.

Solar photovoltaic power generation has the characteristics of intermittence and randomness, which makes it a challenge to accurately predict solar power generation power, and it is difficult to achieve the desired effect. Therefore, by fully considering the relationship between power generation data and climate factors, a new prediction method is proposed based on sliced bidirectional long short term memory and the attention mechanism. The prediction results show that the presented model has higher accuracy than the common prediction models multi-layer perceptron, convolution neural network, long short term memory and bidirectional long short term memory. The presented sliced bidirectional cyclic network has high prediction accuracy by low root mean square error and mean absolute error of 1.999 and 1.159 respectively. The time cost is only 24.32% of that of long short term memory network and 13.76% of that of bidirectional long short term memory network.

William Gilpin

Chaos and unpredictability are traditionally synonymous, yet large-scale machine-learning methods recently have demonstrated a surprising ability to forecast chaotic systems well beyond typical predictability horizons. However, recent works disagree on whether specialized methods grounded in dynamical systems theory, such as reservoir computers or neural ordinary differential equations, outperform general-purpose large-scale learning methods such as transformers or recurrent neural networks. These prior studies perform comparisons on few individually chosen chaotic systems, thereby precluding robust quantification of how statistical modeling choices and dynamical invariants of different chaotic systems jointly determine empirical predictability. Here, we perform the largest to-date comparative study of forecasting methods on the classical problem of forecasting chaos: we benchmark 24 state-of-the-art forecasting methods on a crowdsourced database of 135 low-dimensional systems with 17 forecast metrics. We find that large-scale, domain-agnostic forecasting methods consistently produce predictions that remain accurate up to two dozen Lyapunov times, thereby accessing a long-horizon forecasting regime well beyond classical methods. We find that, in this regime, accuracy decorrelates with classical invariant measures of predictability like the Lyapunov exponent. However, in data-limited settings outside the long-horizon regime, we find that physics-based hybrid methods retain a comparative advantage due to their strong inductive biases.

Sajeda Pervin, Mohammad Nazari Ismail, Abu Hanifa Md Noman

The role played by microfinancing in the empowerment of women has been a subject of debate in recent literature. By employing the case study method, this paper explores the influencing determinants. Data was obtained from a field interview comprised of 20 female microfinance borrowers and their male family members, as well as focus group discussions and participant observation. The economic, social, and political empowerment of the interviewed women were assessed using Kabeer’s empowerment framework, and the results reveal that microfinancing does not influence the economic and political dimensions of female empowerment; instead, microfinancing was observed to empower women socially, particularly with respect to their participation in major decision-making. The results further indicate that the age, family type, educational level, financial literacy, and training of female microfinance clients play important roles in their empowerment.

Ralph Kenna, Bertrand Berche

This is part of an unpublished work in collaboration with Ralph Kenna. It was probably not mature enough at the time it was submitted more than ten years ago and it was rejected by the editors, but some of the ideas had later been published partially in subsequent works. I believe that this "draft" reveals a lot about Ralph's enthusiasm and audacity and deserves to be published now, maybe as a part of his legacy.

Manuel E. Rodrigues, Marcos V. de S. Silva

Black bounces are spacetimes that can describe, depending on certain parameters, black holes or wormholes. In this work, we use a method to obtain the matter content that generates black bounce solutions in general relativity. The method is constructed in a general way, and as models, we apply it to the Simpson--Visser black bounce solution and the Bardeen-type black bounce solution. We obtain that these metrics are solutions of Einstein's equations when we consider the coupling of the gravitational interaction with a phantom scalar field with a nonlinear electrodynamics. The presence of the phantom scalar field is linked to the fact that this type of solution violates the null energy condition. We analyze separately the energy conditions associated with the stress-energy tensor for the scalar field and for the electromagnetic field.

M. S. Novikov

Maintaining political stability and unity of the territory of the state is an important task for any government. It becomes especially relevant in cases where different territories of the state have ethnically different populations. Areas with mixed populations, especially those driven by migration, are potential areas of stress. Reasonable implementation of the rights and freedoms of citizens in economic and cultural terms, freedom of movement, is a guarantee of stable development or at least peaceful migration. An analysis of the history of the creation of German national regions in the USSR shows a picture of the gradual assimilation of the German population or its migration outside the country. The article discusses the creation of a Azovsky Nemetsky (German) National District to ensure economic and cultural rights. The work is carried out on the basis of multifaceted sources. As a result of the fulfillment of the goal of the study — the reconstruction of the history of the region’s reconstruction against the background of the development of the German national movement and the influence of its international obligations on the country’s leadership, the following conclusions can be drawn. The creation of the Azovsky Nemetsky (German) National District is culturally, economically and politically expedient. Of interest there are also the conclusions about the possibilities within the framework of the Azovsky Nemetsky (German) National District to resolve the problems of emigration and migration, as well as the issues of raising the standard of living of the population.

José Omar Varela Herrera, Leiden Liseth Márquez Rodríguez

El artículo tuvo como objetivo, analizar las prácticas pedagógicas interculturales en los licenciados en formación de la Facultad de Bellas Artes de la Universidad Popular del Cesar. Metodológicamente, se enmarcó en la tradición cualitativa desde una perspectiva fenomenológica, utilizando la entrevista como instrumento para recoger información. Los datos revelaron debilidades en los docentes y en los estudiantes, como informantes del proceso investigativo, sobre su conocimiento del enfoque educativo intercultural. La entrevista evidenció que les otorgan significatividad a las prácticas pedagógicas interculturales en la formación del profesorado. Las conclusiones apuntaron hacia la necesidad de aportar una serie de orientaciones para la acción pedagógica a los fines de potenciar y optimizar las prácticas interculturales que, actualmente, son utilizadas por los docentes y estudiantes, con la finalidad de contribuir al abordaje de la interculturalidad en el escenario educativo.

Bernardo Kolling Limberger

Estudos sobre o processamento da leitura bilíngue/multilíngue têm evidenciado de forma robusta que o acesso lexical é não seletivo, havendo uma busca paralela em todos os subsistemas linguísticos. Esse efeito tem sido replicado nas pesquisas mais recentes nas quais são apresentadas sentenças aos participantes. O contexto de sentença também mostra que pode haver coativação sintática, de modo que as representações sintáticas de uma língua possam facilitar o processamento de estruturas semelhantes na outra língua. De forma geral, tais as investigações incluem línguas hegemônicas e majoritárias. Diante disso, o objetivo deste estudo foi investigar o acesso lexical durante o processamento de sentenças em alemão padrão por falantes de hunsriqueano, língua de imigração alemã falada no Brasil. Foi aplicada uma Tarefa de compreensão de sentenças em alemão. Dois grupos participaram da pesquisa: um composto por falantes de hunsriqueano, o outro por não falantes de qualquer língua minoritária de origem alemã. Todos os participantes estudam alemão como língua estrangeira. Os resultados mostram um efeito do compartilhamento de representações semânticas, fonológicas (acesso lexical não seletivo) e sintáticas (coativação sintática) entre hunsriqueano e alemão no processamento de sentenças em alemão. Por meio dos resultados, visamos contribuir com a pesquisa em línguas minoritárias e processamento da leitura, uma relação nem sempre trivial.

Hui Xiao, Ion Grama, Quansheng Liu

Consider the random walk $G_n : = g_n \ldots g_1$, $n \geq 1$, where $(g_n)_{n\geq 1}$ is a sequence of independent and identically distributed random elements with law $μ$ on the general linear group ${\rm GL}(V)$ with $V=\mathbb R^d$. Under suitable conditions on $μ$, we establish Cramér type moderate deviation expansions and local limit theorems with moderate deviations for the coefficients $\langle f, G_n v \rangle$, where $v \in V$ and $f \in V^*$. Our approach is based on the Hölder regularity of the invariant measure of the Markov chain $G_n \!\cdot \! x = \mathbb R G_n v$ on the projective space of $V$ with the starting point $x = \mathbb R v$, under the changed measure.

H. Garcia-Compean, D. Mata-Pacheco

The vacuum transition probabilities between to minima of a scalar field potential in the presence of gravity are studied using the Wentzel-Kramers-Brillouin approximation. First we propose a method to compute these transition probabilities by solving the Wheeler-DeWitt equation in a semi-classical approach for any model of superspace that contains terms of squared as well as linear momenta in the Hamiltonian constraint generalizing in this way previous results. Then we apply this method to compute the transition probabilities for a Friedmann-Lemaitre-Robertson-Walker metric with positive and null curvature and for the Bianchi III metric when the coordinates of minisuperspace obey a Standard Uncertainty Principle and when a Generalized Uncertainty Principle is taken into account. In all cases we compare the results and found that the effect of considering a Generalized Uncertainty Principle is that the probability is enhanced at first but it decays faster so when the corresponding scale factor is big enough the probability is reduced. We also consider the effect of anisotropy and compare the result of the Bianchi III metric with the flat FLRW metric which corresponds to its isotropy limit and comment the differences with previous works.