Axion Isocurvature and Magnetic Monopoles

We propose a simple mechanism to suppress axion isocurvature fluctuations using hidden sector magnetic monopoles. This allows for the Peccei-Quinn scale to be of order the unification scale consistently with high scale inflation.Comment: 13 page

Flat-space Quantum Gravity in AdS/CFT

Motivated by the task of understanding microscopic dynamics of an evolving black hole, we present a scheme describing gauge-fixed continuous time evolution of quantum gravitational processes in asymptotically flat spacetime using the algebra of CFT operators. This allows us to study the microscopic dynamics of the Hawking emission process, although obtaining a full S-matrix may require a modification of the minimal scheme. The role of the operator product expansion is to physically interpret the resulting time evolution by decomposing the Hilbert space of the states for the entire system into those for smaller subsystems. We translate the picture of an evaporating black hole previously proposed by the authors into predictions for nonperturbative properties of the CFTs that have weakly coupled dual gravitational descriptions. We also discuss a possible relationship between the present scheme and a reference frame change in the bulk.Comment: 31 pages, 2 figures; clarifications adde

Relativeness in Quantum Gravity: Limitations and Frame Dependence of Semiclassical Descriptions

Consistency between quantum mechanical and general relativistic views of the world is a longstanding problem, which becomes particularly prominent in black hole physics. We develop a coherent picture addressing this issue by studying the quantum mechanics of an evolving black hole. After interpreting the Bekenstein-Hawking entropy as the entropy representing the degrees of freedom that are coarse-grained to obtain a semiclassical description from the microscopic theory of quantum gravity, we discuss the properties these degrees of freedom exhibit when viewed from the semiclassical standpoint. We are led to the conclusion that they show features which we call extreme relativeness and spacetime-matter duality---a nontrivial reference frame dependence of their spacetime distribution and the dual roles they play as the "constituents" of spacetime and as thermal radiation. We describe black hole formation and evaporation processes in distant and infalling reference frames, showing that these two properties allow us to avoid the arguments for firewalls and to make the existence of the black hole interior consistent with unitary evolution in the sense of complementarity. Our analysis provides a concrete answer to how information can be preserved at the quantum level throughout the evolution of a black hole, and gives a basic picture of how general coordinate transformations may work at the level of full quantum gravity beyond the approximation of semiclassical theory.Comment: 44 pages, 4 figures; typos correcte

Essays on estimation of dynamic games

This thesis considers estimation of discrete choice stationary dynamic games. Chapter 1 shows that when payoffs are linear in the parameters value functions are linear in the parameters and the equation system characterizing the Markovian equilibrium is linear in the parameters. This formulation allows us to estimate the model using Least Squares. We derive an optimal weight matrix for the Least Squares estimator and show that the efficient estimator is a Generalized Least Squares estimator. Chapter 2 shows that when time invariant unobservables are present the efficient estimator is a Generalized Fixed Effects estimator. Time invariant unobservables can be correlated with observed states. We do not need to impose any distributional assumption on time invariant unobservables. Our estimators have a closed form solution. In Chapter 3 we apply the framework developed in Chapters 1 and 2 to analyze the effects of the privatization of public banks on financial development. We build a dynamic entry game to analyze the Brazilian banking market. We show that profits of private banks are positively affected by the number of public branches operating in Brazilian isolated markets. The spill-over generated by public banks is quantified based on a dynamic oligopoly model. A counterfactual in which public banks are privatized is examined. It shows that the number of active branches operating in the long-run in a small market drops significantly

Spacetime Equals Entanglement

We study the Hilbert space structure of classical spacetimes under the assumption that entanglement in holographic theories determines semiclassical geometry. We show that this simple assumption has profound implications; for example, a superposition of classical spacetimes may lead to another classical spacetime. Despite its unconventional nature, this picture admits the standard interpretation of superpositions of well-defined semiclassical spacetimes in the limit that the number of holographic degrees of freedom becomes large. We illustrate these ideas using a model for the holographic theory of cosmological spacetimes.Comment: 6 pages, 2 figures; v2: remarks on time evolution revised, v3: matches published versio

GRUPO OPERATIVO COM ESTUDANTES DE ENFERMAGEM: VIVÊNCIA EM UMA LIGA ACADÊMICA DE ONCOLOGIA

Objetivo: descrever uma atividade grupal desenvolvida em uma Liga Acadêmica de Prevenção ao Câncer. Método: relato de experiência em um grupo operativo realizado no primeiro semestre de 2019, em uma universidade pública do interior de São Paulo, com 27 graduandos do curso de Enfermagem com idades entre 17 e 25 anos, cursando entre o primeiro e o sétimo períodos letivos. Resultados: nas discussões grupais emergiram quatro temas, evidenciando aspectos do contexto de adoecimento por câncer, como estigmas, medos, anseios, fantasias, vivências do câncer como uma doença agressiva e limitante para o acometido e sua família, além de recursos de enfrentamento, como a religiosidade/espiritualidade. Conclusão: a atividade grupal desenvolvida em uma Liga Acadêmica de Prevenção ao Câncer evidenciou a importância de a oncologia ser trabalhada na formação de Enfermagem, capacitando os estudantes para lidarem com situações de intervenção e prepararem-se emocionalmente para os desafios que podem emergir nesse campo de atuação futura.Descritores: Educação em Enfermagem. Educação em Saúde. Grupos Focais. Oncologia. Psico-Oncologia