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We study quasinormal modes of massive scalar perturbations in Kerr black holes using the isomonodromic method. For arbitrary scalar masses $M \mu$ and black hole spins $a/M$, we numerically determine the quasinormal frequencies for various orbital $\ell$, azimuthal $m$, and overtone $n$ numbers. In particular, we derive an analytic expression for frequencies of the zero-damping modes near the extremal limit $a/M \rightarrow 1$. For $\ell=m=1$, we reveal that the fundamental mode becomes a damped mode (rather than a zero-damping mode) if the scalar field is sufficiently heavy. By exploring the parameter space, we find numerical evidence for level-crossing between the longest-living mode and the first overtone at an exceptional point $(M\mu)_c \simeq 0.3704981$ and $(a/M)_c\simeq 0.9994660$., Comment: 20 pages, 13 graphics, 2 figures, 2 tables

We employ the isomonodromic method to study linear scalar massive perturbations of Kerr black holes for generic scalar masses $M\mu$ and generic black hole spins $a/M$. A degeneracy between the longest-living quasinormal mode and the first overtone is found for $(M\mu)_c \simeq 0.3704981$ and $(a/M)_c\simeq 0.9994660$. We show that the longest-living mode and the first overtone change continuously into each other as we vary the parameters around the point of degeneracy, providing evidence for the existence of a geometric phase around an exceptional point. We interpret our findings through a thermodynamic analogy., Comment: v2: 8 pages, 4 figures. Typos corrected and references added

We propose a relation the expansions of regular and irregular semiclassical conformal blocks at different branch points making use of the connection between the accessory parameters of the BPZ decoupling equations to the logarithm derivative of isomonodromic tau functions. We give support for these relations by considering two eigenvalue problems for the confluent Heun equations obtained from the linearized perturbation theory of black holes. We first derive the large frequency expansion of the spheroidal equations, and then compare numerically the excited quasi-normal mode spectrum for the Schwarzschild case obtained from the large frequency expansion to the one obtained from the low frequency expansion and with the literature, indicating that the relations hold generically in the complex modulus plane., Comment: 24 pages, 1 figure, 2 tables. Version published at JHEP

We study the quasinormal modes (QNMs) of a charged scalar field on a Reissner-Nordstr\"{o}m-anti-de Sitter (RN-AdS$_{5}$) black hole in the small radius limit by using the isomonodromic method. We also derive the low-temperature expansion of the fundamental QNM frequency. Finally, we provide numerical evidence that instabilities appear in the small radius limit for large values of the charge of the scalar field., Comment: 16 pages, 3 figures

We investigate spin-$0$ and spin-$\frac{1}{2}$ perturbations for non-extremal and extremal Reissner-Nordstr\"om backgrounds using the isomonodromic method. We calculate the fundamental quasinormal modes (QNMs) associated with each perturbation as a function of the electromagnetic coupling $qQ$ and ratio $Q/M$. After corroborating the literature values for generic $qQ$ and $Q/M$, we turn to study the near-extremal limit. In parallel with the study of QNMs for the Kerr geometry, we find the existence of "non-damping" modes for $qQ$ above a spin-dependent critical value, and locate the bifurcation point in the $q-Q$ parameter space., Comment: REVTeX4.2, 16 pages, 6 figures, 4 tables

We conduct an analysis of the quasi-normal modes for generic spin perturbations of the Kerr black hole using the isomonodromic method. The strategy consists of solving the Riemann-Hilbert map relating the accessory parameters of the differential equations involved to monodromy properties of the solutions, using the $\tau$-function for the Painlev\'e V transcendent. We show good accordance of the method with the literature for generic rotation parameter $a

We study the low-temperature limit of scalar perturbations of the Kerr-AdS$_{5}$ black-hole for generic rotational parameters. We motivate the study by considering real-time holography of small black hole backgrounds. Using the isomonodromic technique, we show that corrections to the extremal limit can be encoded in the monodromy parameters of the Painlev\'e V transcendent, whose expansion is given in terms of irregular chiral conformal blocks. After discussing the contribution of the intermediate states to the quasi-normal modes, we perform a numerical analysis of the low-lying frequencies. We find that the fundamental mode is perturbatively stable at low temperatures for small black holes and that excited perturbations are superradiant, as expected from thermodynamical considerations. We close by considering the holographic interpretation of the unstable modes and the decaying process., Comment: 53 pages, 9 figures. Expression for the fundamental QNM frequency revised and comparison with numerical results included. Version accepted for publication in JHEP

We study the quasinormal modes (QNMs) of a charged scalar field on a Reissner-Nordstr\"{o}m-anti-de Sitter (RN-AdS$_{5}$) black hole in the small radius limit by using the isomonodromic method. We also derive the low-temperature expansion of the fundamental QNM frequency. Finally, we provide numerical evidence that instabilities appear in the small radius limit for large values of the charge of the scalar field., Comment: 16 pages, 3 figures

We investigate spin-$0$ and spin-$\frac{1}{2}$ perturbations for non-extremal and extremal Reissner-Nordstr\"om backgrounds using the isomonodromic method. We calculate the fundamental quasinormal modes (QNMs) associated with each perturbation as a function of the electromagnetic coupling $qQ$ and ratio $Q/M$. After corroborating the literature values for generic $qQ$ and $Q/M$, we turn to study the near-extremal limit. In parallel with the study of QNMs for the Kerr geometry, we find the existence of "non-damping" modes for $qQ$ above a spin-dependent critical value, and locate the bifurcation point in the $q-Q$ parameter space., Comment: REVTeX4.2, 16 pages, 6 figures, 4 tables

We conduct an analysis of the quasi-normal modes for generic spin perturbations of the Kerr black hole using the isomonodromic method. The strategy consists of solving the Riemann-Hilbert map relating the accessory parameters of the differential equations involved to monodromy properties of the solutions, using the $\tau$-function for the Painlev\'e V transcendent. We show good accordance of the method with the literature for generic rotation parameter $a

We analyze the Ansatz of separability for Maxwell equations in generically spinning, five-dimensional Kerr-AdS black holes. We find that the parameter \mu introduced in a previous work by O. Lunin can be interpreted as apparent singularities of the resulting radial and angular equations. Using isomonodromy deformations, we describe a non-linear symmetry of the system, under which \mu is tied to the Painlev\'e VI transcendent. By translating the boundary conditions imposed on the solutions of the equations for quasinormal modes in terms of monodromy data, we find a procedure to fix \mu and study the behavior of the quasinormal modes in the limit of fast spinning small black holes., Comment: Minor comments on fixing of parameters and polarizations, 31 pages, 2 figures, JHEP style

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., isbn: 9786586002744, Pages: 39-46

We analyze the Ansatz of separability for Maxwell equations in generically spinning, five-dimensional Kerr-AdS black holes. We find that the parameter \mu introduced in a previous work by O. Lunin can be interpreted as apparent singularities of the resulting radial and angular equations. Using isomonodromy deformations, we describe a non-linear symmetry of the system, under which \mu is tied to the Painlev\'e VI transcendent. By translating the boundary conditions imposed on the solutions of the equations for quasinormal modes in terms of monodromy data, we find a procedure to fix \mu and study the behavior of the quasinormal modes in the limit of fast spinning small black holes., Comment: Minor comments on fixing of parameters and polarizations, 31 pages, 2 figures, JHEP style

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., Pages: 39-46

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., Pages: 39-46

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., isbn: 9786586002744, Pages: 39-46

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., isbn: 9786586002744, Pages: 39-46

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., isbn: 9786586002744, Pages: 39-46

Projetos espaciais requerem um alto nível organizacional para seu sucesso. O nível de assertividade é proveniente da escolha dos métodos de engenharia mais adequados para propor, construir, verificar, validar, operar e descartar os sistemas. Dentre os métodos empregados pelos engenheiros do INPE, existem a Engenharia de Requisitos e a Engenharia de Sistemas. Este trabalho analisou, classificou e organizou os interessados e afetados, ou stakeholders, do sistema Bazooka Cansat, operada no evento Segundo CubeDesign. Em seguida foram feitas entrevistas com os interessados e as necessidades coletadas, analisadas e transformadas em requisitos. Os requisitos foram balanceados segundo as necessidades dos entrevistados e se mostraram eficazes para as etapas subsequentes de montagem, integração, testes e uso., isbn: 9786586002744, Pages: 39-46

Quasinormal modes of usual, four dimensional, Kerr black holes are described by certain solutions of a confluent Heun differential equation. In this work, we express these solutions in terms of the connection matrices for a Riemann-Hilbert problem, which was recently solved in terms of the Painlev\'e V transcendent. We use this formulation to generate the small-frequency expansion for the angular spheroidal harmonic eigenvalue, and derive conditions on the monodromy properties for the radial modes. Using exponentiation, we relate the accessory parameter to a semi-classical conformal description and discuss the properties of the operators involved. For the radial equation, while the operators at the horizons have Liouville momenta proportional to the entropy intake, we find that spatial infinity is described by a Whittaker operator., Comment: REVTeX4.2, 17 pages

Temos o prazer de apresentar o 10° Workshop em Engenharia e Tecnologia Espaciais (WETE), que será realizado nos dias 7, 8 e 9 de agosto de 2019 no Auditório Fernando de Mendonça, nas dependências do Instituto Nacional de Pesquisas Espaciais em São José dos Campos. O WETE é um evento promovido pelos alunos da Pós-Graduação em Engenharia e Tecnologia Espaciais (PG-ETE). A PG-ETE possui 4 Áreas de Concentração: Engenharia e Gerenciamento de Sistemas Espaciais (CSE), Combustão e Propulsão (PCP), Mecânica Espacial e Controle (CMC) e Materiais e Sensores (CMS). As linhas de pesquisa distribuídas dentro de cada área de concentração se complementam e, dessa forma, é gerado o conhecimento necessário para os estudos relacionados à Engenharia Espacial. Dessa maneira, o WETE tem como um de seus objetivos promover a integração entre os discentes e docentes das diferentes Áreas de Concentração do curso, viabilizando uma discussão em torno dos trabalhos, de modo a sugerir melhorias, apresentar outros pontos de vista e desenvolver novas ideias. O WETE também cumpre o papel fundamental de: apresentar aos novos alunos os trabalhos que estão sendo executados no contexto da PG-ETE; divulgar à comunidade cientifica os trabalhos em andamento; estimular um ambiente criativo, inovador e desafiador e de produção científica. Cada WETE é sempre uma nova oportunidade de trocar conhecimentos na área de engenharia e tecnologia espaciais., Number of Pages: 32

Quasinormal modes of usual, four dimensional, Kerr black holes are described by certain solutions of a confluent Heun differential equation. In this work, we express these solutions in terms of the connection matrices for a Riemann-Hilbert problem, which was recently solved in terms of the Painlev\'e V transcendent. We use this formulation to generate the small-frequency expansion for the angular spheroidal harmonic eigenvalue, and derive conditions on the monodromy properties for the radial modes. Using exponentiation, we relate the accessory parameter to a semi-classical conformal description and discuss the properties of the operators involved. For the radial equation, while the operators at the horizons have Liouville momenta proportional to the entropy intake, we find that spatial infinity is described by a Whittaker operator., Comment: JHEP style, 24 pages

Temos o prazer de apresentar o 10º Workshop em Engenharia e Tecnologia Espaciais (WETE), que será realizado nos dias 7, 8 e 9 de agosto de 2019 no Auditório Fernando de Mendonça, nas dependências do Instituto Nacional de Pesquisas Espaciais em São José dos Campos. O WETE é um evento promovido pelos alunos da Pós-Graduação em Engenharia e Tecnologia Espaciais (PG-ETE). A PG-ETE possui 4 Áreas de Concentração: Engenharia e Gerenciamento de Sistemas Espaciais (CSE), Combustão e Propulsão (PCP), Mecânica Espacial e Controle (CMC) e Materiais e Sensores (CMS). As linhas de pesquisa distribuídas dentro de cada área de concentração se complementam e, dessa forma, é gerado o conhecimento necessário para os estudos relacionados à Engenharia Espacial. Dessa maneira, o WETE tem como um de seus objetivos promover a integração entre os discentes e docentes das diferentes Áreas de Concentração do curso, viabilizando uma discussão em torno dos trabalhos, de modo a sugerir melhorias, apresentar outros pontos de vista e desenvolver novas ideias. O WETE também cumpre o papel fundamental de: apresentar aos novos alunos os trabalhos que estão sendo executados no contexto da PG-ETE; divulgar à comunidade cientifica os trabalhos em andamento; estimular um ambiente criativo, inovador e desafiador e de produção científica. Cada WETE é sempre uma nova oportunidade de trocar conhecimentos na área de engenharia e tecnologia espaciais., Number of Pages: 32

Temos o prazer de apresentar o 10º Workshop em Engenharia e Tecnologia Espaciais (WETE), que será realizado nos dias 7, 8 e 9 de agosto de 2019 no Auditório Fernando de Mendonça, nas dependências do Instituto Nacional de Pesquisas Espaciais em São José dos Campos. O WETE é um evento promovido pelos alunos da Pós-Graduação em Engenharia e Tecnologia Espaciais (PG-ETE). A PG-ETE possui 4 Áreas de Concentração: Engenharia e Gerenciamento de Sistemas Espaciais (CSE), Combustão e Propulsão (PCP), Mecânica Espacial e Controle (CMC) e Materiais e Sensores (CMS). As linhas de pesquisa distribuídas dentro de cada área de concentração se complementam e, dessa forma, é gerado o conhecimento necessário para os estudos relacionados à Engenharia Espacial. Dessa maneira, o WETE tem como um de seus objetivos promover a integração entre os discentes e docentes das diferentes Áreas de Concentração do curso, viabilizando uma discussão em torno dos trabalhos, de modo a sugerir melhorias, apresentar outros pontos de vista e desenvolver novas ideias. O WETE também cumpre o papel fundamental de: apresentar aos novos alunos os trabalhos que estão sendo executados no contexto da PG-ETE; divulgar à comunidade cientifica os trabalhos em andamento; estimular um ambiente criativo, inovador e desafiador e de produção científica. Cada WETE é sempre uma nova oportunidade de trocar conhecimentos na área de engenharia e tecnologia espaciais., Number of Pages: 32

Temos o prazer de apresentar o 10º Workshop em Engenharia e Tecnologia Espaciais (WETE), que será realizado nos dias 7, 8 e 9 de agosto de 2019 no Auditório Fernando de Mendonça, nas dependências do Instituto Nacional de Pesquisas Espaciais em São José dos Campos. O WETE é um evento promovido pelos alunos da Pós-Graduação em Engenharia e Tecnologia Espaciais (PG-ETE). A PG-ETE possui 4 Áreas de Concentração: Engenharia e Gerenciamento de Sistemas Espaciais (CSE), Combustão e Propulsão (PCP), Mecânica Espacial e Controle (CMC) e Materiais e Sensores (CMS). As linhas de pesquisa distribuídas dentro de cada área de concentração se complementam e, dessa forma, é gerado o conhecimento necessário para os estudos relacionados à Engenharia Espacial. Dessa maneira, o WETE tem como um de seus objetivos promover a integração entre os discentes e docentes das diferentes Áreas de Concentração do curso, viabilizando uma discussão em torno dos trabalhos, de modo a sugerir melhorias, apresentar outros pontos de vista e desenvolver novas ideias. O WETE também cumpre o papel fundamental de: apresentar aos novos alunos os trabalhos que estão sendo executados no contexto da PG-ETE; divulgar à comunidade cientifica os trabalhos em andamento; estimular um ambiente criativo, inovador e desafiador e de produção científica. Cada WETE é sempre uma nova oportunidade de trocar conhecimentos na área de engenharia e tecnologia espaciais., Number of Pages: 32

An analytic expression for the scalar quasinormal modes of the generic, spinning Kerr-$\mathrm{AdS_5}$ black holes was previously proposed by the authors in ref. 1, in terms of transcendental equations involving the Painlev\'e VI (PVI) $\tau$ function. In this work, we carry out a numerical investigation of the modes for generic rotation parameters, comparing implementations of expansions for the PVI $\tau$ function both in terms of conformal blocks (Nekrasov functions) and Fredholm determinants. We compare the results with standard numerical methods for the subcase of Schwarzschild black holes. We then derive asymptotic formulas for the angular eigenvalues and the quasinormal modes in the small black hole limit for generic scalar mass and discuss, both numerically and analytically, the appearance of superradiant modes., Comment: JHEP style, 42 pages, 3 figures, 3 tables; Updated discussion on the superradiant modes

An analytic expression for the scalar quasinormal modes of the generic, spinning Kerr-$\mathrm{AdS_5}$ black holes was previously proposed by the authors in ref. 1, in terms of transcendental equations involving the Painlev\'e VI (PVI) $\tau$ function. In this work, we carry out a numerical investigation of the modes for generic rotation parameters, comparing implementations of expansions for the PVI $\tau$ function both in terms of conformal blocks (Nekrasov functions) and Fredholm determinants. We compare the results with standard numerical methods for the subcase of Schwarzschild black holes. We then derive asymptotic formulas for the angular eigenvalues and the quasinormal modes in the small black hole limit for generic scalar mass and discuss, both numerically and analytically, the appearance of superradiant modes., Comment: JHEP style, 42 pages, 3 figures, 3 tables; Updated discussion on the superradiant modes

We review the relation between four-dimensional global conformal blocks and field propagation in ${\rm AdS_5}$. Following the standard argument that marginal perturbations should backreact in the geometry, we turn to the study of scalar fields in the generic Kerr-${\rm AdS_5}$ geometry. On one hand, the result for scattering coefficients can be obtained exactly using the isomonodromy technique, giving exact expressions in terms of $c=1$ chiral conformal blocks. On the other hand, one can use the analogy between the scalar field equations to the Level 2 null field Ward identity in two dimensional Liouville field theory to write approximate expressions for the same coefficients in terms of semi-classical chiral Liouville conformal blocks. Surprisingly, the conformal block thus constructed has a well-behaved interpretation in terms of Liouville vertex operators., Comment: JHEP3 style, 34 pages, 2 figures; Minor changes in the text and a corrected near-extremal radial monodromy calculation. Version accepted to JHEP

Usual gauge fixing procedures in classical general relativity rely on the existence of solutions of a second order wave equation. We propose to use the equation to relate asymptotic symmetries at infinity to asymptotic symmetries of a black hole horizon, in tune with recent proposals. We illustrate the construction for the BTZ and four-dimensional Kerr black holes. We find in both cases a realization of the group of diffeomorphisms of the circle $S^1$., Comment: JHEP3 style, 27 pages, 2 figures, References added, typos corrected

We review the relation between four-dimensional global conformal blocks and field propagation in ${\rm AdS_5}$. Following the standard argument that marginal perturbations should backreact in the geometry, we turn to the study of scalar fields in the generic Kerr-${\rm AdS_5}$ geometry. On one hand, the result for scattering coefficients can be obtained exactly using the isomonodromy technique, giving exact expressions in terms of $c=1$ chiral conformal blocks. On the other hand, one can use the analogy between the scalar field equations to the Level 2 null field Ward identity in two dimensional Liouville field theory to write approximate expressions for the same coefficients in terms of semi-classical chiral Liouville conformal blocks. Surprisingly, the conformal block thus constructed has a well-behaved interpretation in terms of Liouville vertex operators., Comment: JHEP3 style, 34 pages, 2 figures; Minor changes in the text and a corrected near-extremal radial monodromy calculation. Version accepted to JHEP

Usual gauge fixing procedures in classical general relativity rely on the existence of solutions of a second order wave equation. We propose to use the equation to relate asymptotic symmetries at infinity to asymptotic symmetries of a black hole horizon, in tune with recent proposals. We illustrate the construction for the BTZ and four-dimensional Kerr black holes. We find in both cases a realization of the group of diffeomorphisms of the circle $S^1$., Comment: JHEP3 style, 27 pages, 2 figures, References added, typos corrected

We point out a simple relation between the bulk field at an arbitrary radial position and the boundary OPE, by placing some old work by Ferrara, Gatto, Grillo and Parisi in the AdS/CFT context. This gives us, in principle, a prescription for extracting the classical bulk field from the boundary conformal block, and also clarifies why the latter is computed by a geodesic Witten diagram. We apply this prescription to the BTZ black hole - viewed as a pure state created by the insertion of a heavy operator in the boundary CFT_2 - and use it to relate a classical field in the bulk to a heavy-light Virasoro conformal block in the boundary. In particular, we obtain a relation between the radial bulk position and the conformal ratios in the boundary CFT. We use this to show that the singular points of the radial bulk equation occur when the dual boundary operators approach each other and that the associated bulk monodromies map to monodromies of the (appropriately transformed) conformal block, thus providing a CFT interpretation of the radial monodromy., Comment: 30 pp, 3 figures

We point out a simple relation between the bulk field at an arbitrary radial position and the boundary OPE, by placing some old work by Ferrara, Gatto, Grillo and Parisi in the AdS/CFT context. This gives us, in principle, a prescription for extracting the classical bulk field from the boundary conformal block, and also clarifies why the latter is computed by a geodesic Witten diagram. We apply this prescription to the BTZ black hole - viewed as a pure state created by the insertion of a heavy operator in the boundary CFT_2 - and use it to relate a classical field in the bulk to a heavy-light Virasoro conformal block in the boundary. In particular, we obtain a relation between the radial bulk position and the conformal ratios in the boundary CFT. We use this to show that the singular points of the radial bulk equation occur when the dual boundary operators approach each other and that the associated bulk monodromies map to monodromies of the (appropriately transformed) conformal block, thus providing a CFT interpretation of the radial monodromy., Comment: 30 pp, 3 figures

We study the scattering of a massless scalar field in a generic Kerr background. Using a particular gauge choice based on the current conservation of the radial equation, we give a generic formula for the scattering coefficient in terms of the composite monodromy parameter $\sigma$ between the inner and the outer horizons. Using the isomonodromy flow, we calculate $\sigma$ exactly in terms of the Painlev\'e V $\tau$-function. We also show that the eigenvalue problem for the angular equation (spheroidal harmonics) can be calculated using the same techniques. We use recent developments relating the Painlev\'e V $\tau$-function to Liouville irregular conformal blocks to claim that this scattering problem is solved in the combinatorial sense, with known expressions for the $\tau$-function near the critical points., Comment: version accepted at JHEP, JHEP style, 23 pages. Major revision with overall rewriting and including discussion about the angular equation and asymptotics of wavefunctions

We discuss the existence of monodromies associated with the singular points of the eigenvalue problem for the Rabi model. The complete control of the full monodromy data requires the taming of the Stokes phenomenon associated with the unique irregular singular point. The monodromy data, in particular the composite monodromy, are written in terms of the parameters of the model via the isomonodromy method and the tau-function of the Painlev\'e V. These data provide a systematic way to obtain the quantized spectrum of the Rabi model., Comment: 6 pages, two-columns

Scattering data can be generically described in terms of monodromies. Here we obtain scattering amplitudes for conformally coupled scalar fields in Kerr-de Sitter black holes using this monodromy technique. The only non-trivial parameter, the composite monodromy parameter $\sigma_{ij}$ between two regular singular points, can be solved implicitily in terms of the Painlev\'e VI $\tau$-function. The application of the Virasoro conformal blocks to solve the latter can now be interpreted as a verification of the striking relationship between conformal symmetry and black holes., Comment: JHEP style, 2 figures, 35 pages

Scattering data can be generically described in terms of monodromies. Here we obtain scattering amplitudes for conformally coupled scalar fields in Kerr-de Sitter black holes using this monodromy technique. The only non-trivial parameter, the composite monodromy parameter $\sigma_{ij}$ between two regular singular points, can be solved implicitily in terms of the Painlev\'e VI $\tau$-function. The application of the Virasoro conformal blocks to solve the latter can now be interpreted as a verification of the striking relationship between conformal symmetry and black holes., Comment: JHEP style, 2 figures, 35 pages

We discuss the existence of monodromies associated with the singular points of the eigenvalue problem for the Rabi model. The complete control of the full monodromy data requires the taming of the Stokes phenomenon associated with the unique irregular singular point. The monodromy data, in particular the composite monodromy, are written in terms of the parameters of the model via the isomonodromy method and the tau-function of the Painlev\'e V. These data provide a systematic way to obtain the quantized spectrum of the Rabi model., Comment: 6 pages, two-columns

We study the scattering of a massless scalar field in a generic Kerr background. Using a particular gauge choice based on the current conservation of the radial equation, we give a generic formula for the scattering coefficient in terms of the composite monodromy parameter $\sigma$ between the inner and the outer horizons. Using the isomonodromy flow, we calculate $\sigma$ exactly in terms of the Painlev\'e V $\tau$-function. We also show that the eigenvalue problem for the angular equation (spheroidal harmonics) can be calculated using the same techniques. We use recent developments relating the Painlev\'e V $\tau$-function to Liouville irregular conformal blocks to claim that this scattering problem is solved in the combinatorial sense, with known expressions for the $\tau$-function near the critical points., Comment: version accepted at JHEP, JHEP style, 23 pages. Major revision with overall rewriting and including discussion about the angular equation and asymptotics of wavefunctions

We consider the dynamics of the Sorkin-Johnston (SJ) state for a massless scalar field in two dimensions. We conduct a study of the renormalized stress-tensor by a subtraction procedure, and compare the results with those of the conformal vacuum, with an important contribution from correction term. We find a large trace anomaly and compute backreaction effects to two dimensional (Liouville) gravity. We find a natural interpretation for the mirror behavior of the SJ state described in previous works., Comment: 8 pages, 1 figure. RevTeX 4.1

We apply the method of isomonodromy to study the scattering of a generic Kerr-NUT-(A)dS black hole. For generic values of the charges, the problem is related to the connection problem of the Painlev\'e VI transcendent. We review a few facts about Painlev\'e VI, Garnier systems and the Hamiltonian structure of flat connections in the Riemann sphere. We then outline a method for computing the scattering amplitudes based on Hamilton-Jacobi structure of Painlev\'e, and discuss the implications of the generic result to black hole complementarity., Comment: 40 pages, 4 figures, JHEP style

The Kerr theorem is revisited as part of the twistor program in six dimensions. The relationship between pure spinors and integrable 3-planes is investigated. The real condition for Lorentzian spacetimes is seen to induce a projective property in the space of solutions, reminiscent of the quaternionic structure of the 6-dimensional Lorentz group. The twistor equation (or Killing spinor equations generically) also has an interpretation as integrable null planes and a family of Einstein spacetimes with this property are presented in the Kerr-Schild fashion., Comment: JHEP style, 19 pages, minor corrections. Matches printed version

We consider the dynamics of the Sorkin-Johnston (SJ) state for a massless scalar field in two dimensions. We conduct a study of the renormalized stress-tensor by a subtraction procedure, and compare the results with those of the conformal vacuum, with an important contribution from correction term. We find a large trace anomaly and compute backreaction effects to two dimensional (Liouville) gravity. We find a natural interpretation for the mirror behavior of the SJ state described in previous works., Comment: 8 pages, 1 figure. RevTeX 4.1

We apply the method of isomonodromy to study the scattering of a generic Kerr-NUT-(A)dS black hole. For generic values of the charges, the problem is related to the connection problem of the Painlev\'e VI transcendent. We review a few facts about Painlev\'e VI, Garnier systems and the Hamiltonian structure of flat connections in the Riemann sphere. We then outline a method for computing the scattering amplitudes based on Hamilton-Jacobi structure of Painlev\'e, and discuss the implications of the generic result to black hole complementarity., Comment: 40 pages, 4 figures, JHEP style

The Kerr theorem is revisited as part of the twistor program in six dimensions. The relationship between pure spinors and integrable 3-planes is investigated. The real condition for Lorentzian spacetimes is seen to induce a projective property in the space of solutions, reminiscent of the quaternionic structure of the 6-dimensional Lorentz group. The twistor equation (or Killing spinor equations generically) also has an interpretation as integrable null planes and a family of Einstein spacetimes with this property are presented in the Kerr-Schild fashion., Comment: JHEP style, 19 pages, minor corrections. Matches printed version

Lima W.C., Lima D.A.S.D., Rodrigues M.C., Quessada A.M., Último A.P. & Pinheiro B.C. [Rectal prolapse in agouti (Dasyprocta aguti) - Case report.] Prolapso retal em cutia (Dasyprocta aguti) - Relato de caso. Revista Brasileira de Medicina Veterinária, 36(4):409-411, 2014. Curso de Pós-Graduação em Ciência Animal, Centro de Ciências Agrárias, Universidade Federal do Piauí, Campus Socopo, Teresina, PI 64049-550, Brasil. E-mail: atsocamil@yahoo.com.br The clinical signs and treatment of rectal prolapse in agouti (Dasyprocta agouti) are described in the present report. The animal, coming from the Nucleus of wild animals of the Federal University of Piauí, was admited in Veterinary Hospital of the institution with a reddish and shiny mass out of the anus. At the clinic examination rectal prolapse was diagnosed. The rectum was manually repositioned and was made a purse-string suture. However, the prolapse relapsed, then was performed colopexy following celiotomy, which was efficient to reduce rectal prolapse in the agouti., No presente relato são descritos os sinais clínicos e o tratamento de prolapso retal em cutia (Dasyprocta aguti). O animal, oriundo do Nú- cleo de Animais Silvestres da Universidade Federal do Piauí, foi atendido no Hospital Veterinário da instituição com relato de presença de massa avermelhada e brilhosa saindo do ânus. Ao exame clínico, diagnosticou-se prolapso retal, sendo que o reto foi reposicionado manualmente e foi feita sutura de contenção. O prolapso recidivou, por isso foi realizada colopexia após celiotomia, a qual se mostrou eficaz para a redução de prolapso retal em cutia.

We study the near horizon geometry of generic Killing horizons constructing suitable coordinates and taking the appropriate scaling limit. We are able to show that the geometry will always show an enhancement of symmetries, and, in the extremal case, will develop a causally disconnected "throat" as expected. We analyze the implications of this to the Kerr/CFT conjecture and the attractor mechanism. We are also able to construct a set of special (pure) spinors associated with the horizon structure using their interpretation as maximally isotropic planes. The structure generalizes the usual reduced holonomy manifold in an interesting way and may be fruitful to the search of new types of compactification backgrounds., Comment: 32 pages, RevTeX4.1, Clarifications on the Attractor Mechanism added. Matches printed version

We study the near horizon geometry of generic Killing horizons constructing suitable coordinates and taking the appropriate scaling limit. We are able to show that the geometry will always show an enhancement of symmetries, and, in the extremal case, will develop a causally disconnected "throat" as expected. We analyze the implications of this to the Kerr/CFT conjecture and the attractor mechanism. We are also able to construct a set of special (pure) spinors associated with the horizon structure using their interpretation as maximally isotropic planes. The structure generalizes the usual reduced holonomy manifold in an interesting way and may be fruitful to the search of new types of compactification backgrounds., Comment: 32 pages, RevTeX4.1, Clarifications on the Attractor Mechanism added. Matches printed version

We propose the holographic principle as a dynamical cutoff for any quantum theory of gravity with a geometric description at low energies, incorporating ideas of effective field theory. We illustrate the proposal by revisiting the problem of defining a measure for homogeneous and isotropic spacetimes coupled to a scalar field and conclude by discussing the implications to the inflationary model., Comment: 18 pages, RevTeX4.1, Clarifications on the geometrical nature of the cutoff. Version matches printed version

A spinorial approach to 6-dimensional differential geometry is constructed and used to analyze tensor fields of low rank, with special attention to the Weyl tensor. We perform a study similar to the 4-dimensional case, making full use of the SO(6) symmetry to uncover results not easily seen in the tensorial approach. Using spinors, we propose a classification of the Weyl tensor by reinterpreting it as a map from 3-vectors to 3-vectors. This classification is shown to be intimately related to the integrability of maximally isotropic subspaces, establishing a natural framework to generalize the Goldberg-Sachs theorem. We work in complexified spaces, showing that the results for any signature can be obtained by taking the desired real slice., Comment: 23 pages; This version matches the published one