Implicit differentiation of variational quantum algorithms

Several quantities important in condensed matter physics, quantum information, and quantum chemistry, as well as quantities required in meta-optimization of machine learning algorithms, can be expressed as gradients of implicitly defined functions of the parameters characterizing the system. Here, we show how to leverage implicit differentiation for gradient computation through variational quantum algorithms and explore applications in condensed matter physics, quantum machine learning, and quantum information. A function defined implicitly as the solution of a quantum algorithm, e.g., a variationally obtained ground- or steady-state, can be automatically differentiated using implicit differentiation while being agnostic to how the solution is computed. We apply this notion to the evaluation of physical quantities in condensed matter physics such as generalized susceptibilities studied through a variational quantum algorithm. Moreover, we develop two additional applications of implicit differentiation -- hyperparameter optimization in a quantum machine learning algorithm, and the variational construction of entangled quantum states based on a gradient-based maximization of a geometric measure of entanglement. Our work ties together several types of gradient calculations that can be computed using variational quantum circuits in a general way without relying on tedious analytic derivations, or approximate finite-difference methods.Comment: 13 pages, 8 figures. The code and data for the article is available at https://github.com/quantshah/quantum-implicit-differentiatio

Self-Supervised Adversarial Imitation Learning

Behavioural cloning is an imitation learning technique that teaches an agent how to behave via expert demonstrations. Recent approaches use self-supervision of fully-observable unlabelled snapshots of the states to decode state pairs into actions. However, the iterative learning scheme employed by these techniques is prone to get trapped into bad local minima. Previous work uses goal-aware strategies to solve this issue. However, this requires manual intervention to verify whether an agent has reached its goal. We address this limitation by incorporating a discriminator into the original framework, offering two key advantages and directly solving a learning problem previous work had. First, it disposes of the manual intervention requirement. Second, it helps in learning by guiding function approximation based on the state transition of the expert's trajectories. Third, the discriminator solves a learning issue commonly present in the policy model, which is to sometimes perform a `no action' within the environment until the agent finally halts.Comment: This paper has been accepted in the International Joint Conference on Neural Networks (IJCNN) 202

Self-Supervised Adversarial Imitation Learning

This paper has been accepted in the International Joint Conference on Neural Networks (IJCNN) 2023Preprin

Predicting the Mpemba Effect Using Machine Learning

The Mpemba Effect -- when a system that is further from equilibrium relaxes faster than a system that is closer -- can be studied with Markovian dynamics in a non-equilibrium thermodynamics framework. The Markovian Mpemba Effect can be observed in a variety of systems including the Ising model. We demonstrate that the Markovian Mpemba Effect can be predicted in the Ising model with several machine learning methods: the decision tree algorithm, neural networks, linear regression, and non-linear regression with the LASSO method. The effectiveness of these methods are compared. Additionally, we find that machine learning methods can be used to accurately extrapolate to data outside the range which they were trained. Neural Networks can even predict the existence of the Mpemba Effect when they are trained only on data in which the Mpemba Effect does not occur. This indicates that information about the effect is contained even in systems where it is not present. All of these results demonstrate that the Mpemba Effect can be predicted in complex, computationally expensive systems, without performing full calculations

Recursos de (in)formalidade nas legendas de La Casa de Papel : legendas como material textual autêntico para a construção de corpora

Trabalho de Conclusão de Curso (graduação) — Universidade de Brasília, Instituto de Letras, Departamento de Línguas Estrangeiras e Tradução, Línguas Estrangeiras Aplicadas ao Multilinguismo e à Sociedade da Informação, 2021.Este projeto final de curso busca unir duas áreas que, por anos, foram tratadas de maneira separada: a legendagem e o corpus. Então, o objetivo principal foi analisar as formas verbo- pronominais e nominais (formais e informais) nas interações de poder presentes nas legendas do segundo episódio da primeira temporada de La Casa de Papel, as quais foram transformadas em corpus. De tal maneira, tem-se como objetivos específicos demonstrar a eficácia do uso de legendas como material representativo para a compilação de corpora, como proposto por Silva (2018), além de evidenciar quais formas são utilizadas como preferência nas relações de poder expressas no seriado. Para tanto, utilizou-se a metodologia adotada por este autor para recolher as legendas, modificá-las quando necessário e construir um corpus paralelo, multilíngue (Espanhol Europeu, Francês Europeu, Português Brasileiro e Inglês Americano) e unidirecional. A partir da análise quantitativa e qualitativa manual, concluiu-se que no seriado ocorrem interações que designam formalidade ou informalidade de maneira similar entre as línguas, diferindo-se pela quantidade de ocorrências e de qual interlocutor parte a fala. Ademais, demonstrou-se que a manifestação de formalidade ou informalidade não se dá não só por pronomes, mas também por formas nominais e verbais.This final course project intends to gather two linguistics fields that, for years, were treated separately: Subtitling and Corpus Linguistics. Then, the main purpose was to analyse the verbal, pronominal and addressing forms presented in the power interactions within the subtitles from the first season and second episode from La casa de Papel. Likewise, the specific purposes were to demonstrate the effectiveness of the use of subtitles as representative material to corpora compilation, as proposed by Silva (2018), as well as to highlight which forms were used as preferable in the power interactions of the series. For this purpose, the methodology proposed by Silva (2018) was used to collect the subtitles, modify them when necessary and to build a parallel, multilingual (European Spanish, European French, Brazilian Portuguese, and American English), and unidirectional. According to the results shown at the end of the analysis, it was possible to conclude that interactions representing formality or informality occur similarly between languages in the series, differing themselves by the frequency of occurrences and who is the interlocutor addressing the speech. Moreover, it demonstrated that the manifestation of formality and informality isn’t only found in pronominal forms, but also in verbal and addressing forms

Zoneamento de risco agroclimático para o limão (citrus aurantifolia) na bacia hidrográfica do Rio Paraná III, Brasil

A lima ácida Tahiti está entre as dez variedades de frutas mais importantes produzidas e consumidas no Brasil, sendo o quinto maior produtor mundial. O objetivo desse trabalho foi realizar o zoneamento de risco agroclimático para o limoeiro (Citrus aurantifolia) na bacia do Rio Paraná III. Foram elaborados mapas temáticos por meio de interpolação e regressões, além de gráficos de probabilidade para a análise do risco. O risco agroclimático para o limoeiro foi pautado nas exigências da espécie, sendo estas, precipitação, deficiência hídrica, temperatura do ar média e máxima, unidade térmica/graus dia e risco de geada. A maior parte da área da bacia foi apta para o cultivo. Não houve áreas inaptas, apenas restritas demonstrando assim, o potencial para a produção na região.El limonero es una de las variedades de frutas más importantes de Brasil, considerado el quinto mayor productor mundial. El propósito de este estudio fue realizar la zonificación del riesgo agroclimático para el limón (Citrus aurantifolia) en la cuenca del río Paraná III. Se elaboraron mapas técnicos mediante interpolación y regresiones, y gráficos para las probabilidades de análisis de riesgos. El riesgo agroclimático para el limón se estableció de acuerdo con los requisitos de la especie, tales como precipitación, deficiencia de agua, temperatura media y máxima del aire, unidad térmica / grados días y riesgo de heladas. La mayor parte del área de la cuenca era apta para el cultivo. No se encontraron áreas inactivas para el cultivo, solo restringir, exhibiendo un potencial considerable para el cultivo de limón, en la región de estudio.The lemon tree is one of the most important variety of fruits in Brazil, considered the fifth largest world producer. The purpose of this study was to carry out agroclimatic risk zoning for lemon (Citrus aurantifolia) in the basin of Paraná River III. Technical maps through interpolation and regressions, and graphics for risks analysis probabilities were elaborated. The agroclimatic risk for lemon was established according to the species requirements, such as precipitation, water deficiency, average and maximum air temperature, thermal unit/degrees days and risk of frost. Larger region in the basin is recommended for cultivation of lemon. It was not found inapt areas for cultivation, only restrict, exhibiting considerable potential for cultivation of lemon, in the region of study