Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Michel Waldschmidt. Articles written in Resonance – Journal of Science Education. Volume 13 Issue 5 May 2008 pp 440-455 General Article. Arithmetic and Cryptography · Michel Waldschmidt · More Details Fulltext PDF ...
Staff Association
2016-01-01
Michel joined CERN early 1979. He started his career in the “Experimental Physics” Division "BCDMS (N4) Muon experiment" and later continued with software support to the GEM project with Emilio Pagiola. He joined the IT Department in 2005 and participated in the implementation of the digital version of PrintShop. Michel is one of the world experts in TeX and LaTex (programming languages for text layout) and is the author of several books on the subject. But at CERN, it is foremost through the Staff Association that we know Michel who successively served as Vice President, secretary and member of the Executive Committee, and since January 2011 and until December 2015, as President of the Staff Association. Do not forget that Michel has consistently been proactive with new proposals and is the initiator of social advances such as SLS (Saved Leaved Scheme) or PRP (Progressive Retirement Programme). At the end of his mandate, Michel expressed his pride fo...
Scaff, Lawrence A.
1981-01-01
This paper investigates the unique intellectual partnership of Max Weber and Robert Michels, with particular emphasis on Weber's influence on Michel's inquiry into the sociology of parties and organization. Concludes with an evaluation of the import of Weber's critique of Michels' work. (DB)
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Vasić Aleksandar N.
2004-01-01
Full Text Available The writers whose real vocation was not music left significant traces in the history of Serbian music critics and essayism of the late 19th century and the first half of the 20th century. Numerous authors, literary historians theoreticians and critics, jurists and theatre historians, wrote successfully on music in Serbian daily newspapers, literary and other magazines, until the Second World War. This study is devoted to Gustav Michel (1868 - 1926, one of the music amateurs who ought to be remembered in the history of Serbian music critics. Gustav Michel was a pharmacist by vocation. He ran a private pharmacy in Belgrade all his life. But he was a musician as well. He played the viola in the second (in chronological order of foundation Serbian String Quartet. The ensemble mostly consisted of amateurs, and it performed standard pieces of chamber music (W. A. Mozart L. v. Beethoven, F. Schubert, F. Mendelsohn-Bartholdy, A. Dvořžak. These musicians had performed public concerts in Belgrade since 1900 up until Michel’s death. Belgrade music critics prised the performances of this string ensemble highly. Gustav Michel was also a music critic. Until now only seven articles, published by this author between 1894 and 1903, in Order (Red, Folk Newspaper (Narodne novine and Serbian Literary Magazine (Srpski književni glasnik have been found. Michel’s preserved articles unambiguously prove that their author had a solid knowledge of music theory and history, the knowledge that exceeded amateurism. Nevertheless, Michel did not burden his first critics with expert language of musicology. Later on, in Serbian Literary Magazine, the magazine which left enough room for music, Michel penetrated more into musical terminology, thus educating slowly forming Serbian concert-going public. The analysis of Michel’s texts showed that he was not, in contrast to the majority of professional music critics, an opponent of virtuosity. Gentle and liberal, he did not
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics. Michel Trottier-McDonald. Articles written in Pramana – Journal of Physics. Volume 79 Issue 5 November 2012 pp 1337-1340 Poster Presentations. Tau reconstruction, energy calibration and identification at ATLAS · Michel Trottier-McDonald on behalf of the ATLAS ...
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Yurij Castelfranchi
2006-03-01
Full Text Available Do we have to drag in the thought of Michel Foucault to show the political (and not neutral, partial and local (and not universal and non-historic, active (and not merely transmissive face of science communication? Do we need the work of the controversial French intellectual to dispute the anxious search – almost a quest like that for the Holy Grail – for the “best practices” in the dissemination of scientific culture? If we read over the pages that Foucault dedicated to words and things, to the archaeology and genealogy of knowledge, to biopolitics, we have few doubts. Two elements, on the one hand the central nature of discourse and “regimes of truth”, on the other the concept of biopower (a “power over bodies”, enable us to reflect both on the important specific features of modern science in comparison with other forms of production and organisation of knowledge, and on the central role of its communication.
Presidents' words - Michel Goossens
Staff Association
2015-01-01
Michel Goossens Already at the beginning of 1955, just a few months after the creation of CERN, the members of the Organization's staff who then numbered less than 200, realized that they had to organize themselves into a corporate body to ensure a formal representation with Management and Member States. The Staff Association was born. As the 27th President of the Staff Association since its inception 60 years ago my task is highly interesting and rewarding, with plenty of responsibility, yet not always simple. Indeed, chosen by one’s peers as primus inter pares, the president is like the conductor of an orchestra, who must first convince his musicians to study the score together, before playing it in harmony. Of course, in my position I can rely on the solid foundations laid by my 26 predecessors, as well as the enthusiasm, loyalty, continuous efforts and perseverance of a core of dedicated collaborators, the elected delegates to the Staff Council. The strength of the Staff Associati...
International Nuclear Information System (INIS)
Papoyan, V.V.
1989-01-01
A Kerr generalized solution for a stationary axially-symmetric gravitational field of rotating self-gravitational objects is given. For solving the problem Einstein equations and their combinations are used. The particular cases: internal and external Schwarzschild solutions are considered. The external solution of the stationary problem is a Kerr solution generalization. 3 refs
Measuring the Michel parameter ξ''
International Nuclear Information System (INIS)
Knowles, P.; Deutsch, J.; Egger, J.; Fetscher, W.; Foroughi, F.; Govaerts, J.; Hadri, M.; Kirch, K.; Kistryn, S.; Lang, J.; Morelle, X.; Naviliat, O.; Ninane, A.; Prieels, R.; Severijns, N.; Simons, L.; Sromicki, J.; Vandormael, S.; Hove, P. van
1999-01-01
Unlike the majority of Michel parameters which are consistent with the Standard Model V-A interaction, the experimental value of ξ''(=0.65±0.36) [1] is poorly known. Our experiment will measure the longitudinal polarization, P L , of positrons emitted from the decay of polarized muons. The value of P L , equal to unity in the Standard Model, will decrease for high energy positrons emitted antiparallel to the muon spin if the combination of Michel parameters ξ''/ξξ' - 1 deviates from the Standard Model value of zero
HR Department
2009-01-01
We deeply regret to announce the death of Mr Michel BLANC on 27 November 2009. Mr BLANC, who was born on 4 April 1952, was a member of the IT Department and had worked at CERN since 1 January 1978. The Director-General has sent his family a message of condolence on behalf of the CERN personnel. Social Affairs It was with great sadness that we learned of the death of our friend and colleague Michel Blanc on the evening of Friday 27 November. Everyone who knew him, especially those who had spent many years with him in the Computer Centre where he worked since his arrival at CERN in 1978, but also his more recent colleagues, will always remember his good humour, his quick wit and his amazing zest for life. He made staunch friends during his thirty years at CERN and often kept in touch with them after they left the Organization. His passion for motorcycling and for walks with his wife, his two sons and his friends were some of his great joys in life. Michel took a well-earned early retirement in Octobe...
Medical education... meet Michel Foucault.
Hodges, Brian D; Martimianakis, Maria A; McNaughton, Nancy; Whitehead, Cynthia
2014-06-01
There have been repeated calls for the greater use of conceptual frameworks and of theory in medical education. Although it is familiar to few medical educators, Michel Foucault's work is a helpful theoretical and methodological source. This article explores what it means to use a 'Foucauldian approach', presents a sample of Foucault's historical-genealogical studies that are relevant to medical education, and introduces the work of four researchers currently undertaking Foucauldian-inspired medical education research. Although they are not without controversy, Foucauldian approaches are employed by an increasing number of scholars and are helpful in shedding light on what it is possible to think, say and be in medical education. Our hope in sharing this Foucauldian work and perspective is that we might stimulate a dialogue that is forward-looking and optimistic about the possibilities for change in medical education. © 2014 John Wiley & Sons Ltd.
Kerr metric in cosmological background
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Vaidya, P C [Gujarat Univ., Ahmedabad (India). Dept. of Mathematics
1977-06-01
A metric satisfying Einstein's equation is given which in the vicinity of the source reduces to the well-known Kerr metric and which at large distances reduces to the Robertson-Walker metric of a nomogeneous cosmological model. The radius of the event horizon of the Kerr black hole in the cosmological background is found out.
In memoriam Michel Butor (1926 – 2016
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Christof Weiand
2016-08-01
Full Text Available Am Mittwoch, dem 24. August 2016, ist Michel Butor gestorben, drei Wochen vor seinem 90. Geburtstag. Als Beispiel für Michel Butors Dichtung soll an dieser Stelle ein Gedicht aus den Textes récents – 37 pages/Neueste Texte – 37 Seiten stehen, die 2012 erstmals erschienen sind:Michel Butor, Textes récents – 37 pages/Neueste Texte – 37 Seiten, aus dem Französischen übersetzt, kommentiert und eingerichtet von Christof Weiand (Heidelberg: Universitätsverlag Winter, 2012.
International Nuclear Information System (INIS)
Vaidya, P.C.; Patel, L.K.; Bhatt, P.V.
1976-01-01
Using Galilean time and retarded distance as coordinates the usual Kerr metric is expressed in form similar to the Newman-Unti-Tamburino (NUT) metric. The combined Kerr-NUT metric is then investigated. In addition to the Kerr and NUT solutions of Einstein's equations, three other types of solutions are derived. These are (i) the radiating Kerr solution, (ii) the radiating NUT solution satisfying Rsub(ik) = sigmaxisub(i)xisub(k), xisub(i)xisup(i) = 0, and (iii) the associated Kerr solution satisfying Rsub(ik) = 0. Solution (i) is distinct from and simpler than the one reported earlier by Vaidya and Patel (Phys. Rev.; D7:3590 (1973)). Solutions (ii) and (iii) gave line elements which have the axis of symmetry as a singular line. (author)
Existe sujeito em Michel Maffesoli?
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Marli Appel da Silva
2010-06-01
Full Text Available Este ensaio discute a concepção de sujeito na abordagem teórica de Michel Maffesoli. As ideias desse autor estão em voga em alguns meios acadêmicos no Brasil e são difundidas por algumas mídias de grande circulação nacional. Entretanto, ao longo de suas obras, os pressupostos que definem quem é o sujeito maffesoliano se encontram pouco clarificados. Portanto, para alcançar o objetivo a que se propõe, este ensaio desenvolve uma análise da epistemologia e da ontologia maffesoliana com a finalidade de compreender as origens dos pressupostos desse autor, ou seja, as teorias e os autores em que Maffesoli se baseou para desenvolver uma visão de sujeito. Com essa compreensão, pretende-se responder à questão: existe sujeito na abordagem teórica de Maffesoli.
Poder disciplinario y capitalismo en Michel Foucault
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Mauro Benente
2017-07-01
Full Text Available Establishing a relationship between the studies of Karl Marx and the research of Michel Foucault is not an easy task. There are readings describing the differences; others might emphasize the similarities while some others criticize Foucault’s developments from a Marxist perspective. In my present work I try to clarify the linkage between the disciplinary power and capitalism of Michel Foucault’s work within the context of the above-mentioned complexities. According to my proposed reading, capitalism does not explain the emergence of the disciplinary power, even if the production and accumulation of capital have applied disciplinary technics.
Selective sensitivity in Kerr microscopy.
Soldatov, I V; Schäfer, R
2017-07-01
A new technique for contrast separation in wide-field magneto-optical Kerr microscopy is introduced. Utilizing the light from eight light emitting diodes, guided to the microscope by glass fibers and being switched synchronously with the camera exposure, domain images with orthogonal in-plane sensitivity can be displayed simultaneously at real-time, and images with pure in-plane or polar contrast can be obtained. The benefit of this new method of contrast separation is demonstrated for Permalloy films, a NdFeB sinter magnet, and a cobalt crystal. Moreover, the new technique is shown to strongly enhance the sensitivity of Kerr microscopy by eliminating parasitic contrast contributions occurring in conventional setups. A doubling of the in-plane domain contrast and a sensitivity to Kerr rotations as low as 0.6 mdeg is demonstrated.
Selective sensitivity in Kerr microscopy
Soldatov, I. V.; Schäfer, R.
2017-07-01
A new technique for contrast separation in wide-field magneto-optical Kerr microscopy is introduced. Utilizing the light from eight light emitting diodes, guided to the microscope by glass fibers and being switched synchronously with the camera exposure, domain images with orthogonal in-plane sensitivity can be displayed simultaneously at real-time, and images with pure in-plane or polar contrast can be obtained. The benefit of this new method of contrast separation is demonstrated for Permalloy films, a NdFeB sinter magnet, and a cobalt crystal. Moreover, the new technique is shown to strongly enhance the sensitivity of Kerr microscopy by eliminating parasitic contrast contributions occurring in conventional setups. A doubling of the in-plane domain contrast and a sensitivity to Kerr rotations as low as 0.6 mdeg is demonstrated.
On Didelphis caudivolvula Kerr and Didelphis vulpecula Kerr
Jentink, F.A.
1885-01-01
Some months ago I was happy enough to procure for our library the rare Animal Kingdom written by Kerr. This autuhor described clearly two Phalangers under the names New-Holland descriptions have Opossum and Vulpine Opossum: these been overlooked by all the naturalist Who have studied the
Wilson loops in Kerr gravitation
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.
1981-01-01
The ordered integrals for several paths in Kerr gravitation is computed in a compact form. When the path is closed its relation with the angular parallel displacement is discussed and the corresponding Wilson loop is calculated. The validity of Mandelstam relations for gauge fields is also explicitly verified. (Author) [pt
Michele Ferro-Luzzi (1938-2015)
2015-01-01
We have learned with great sorrow of the passing away, on 11 May, of Michele Ferro-Luzzi, an engineer well-known to many physicists working at CERN from the late 1960s to the early 2000s. Michele was born in Rome in 1938. He attended primary and secondary schools in Asmara (Eritrea), where his family had moved to in 1939, and then he went to the University of Rome where he obtained a "laurea" in electronic engineering in 1962. After completing his military service he was hired by CERN, in 1965, in the applied physics group, created by the Nuclear Physics (NP) Division Leader, Peter Preiswerk, to support physics teams in the design and construction of detectors, which were becoming more and more complex at that time. Michele’s primary interest was the design of particle beams. He became an expert in beam optics and in all kinds of beam components. For twenty-five years he was the best-known member of his group, involved in nearly all its&nb...
SAN MICHELE. ENTRE CIELO Y MAR / San Michele, between sky and sea
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Pablo Blázquez Jesús
2012-11-01
Full Text Available RESUMEN El cementerio es uno de los tipos arquitectónicos más profundos y metafóricos. El concurso para la ampliación del cementerio de San Michele, convocado en 1998 por la administración Municipal de Venecia, se convierte en un excelente campo de pruebas sobre el que poder analizar el contexto histórico en torno a esta tipología, y su relación con la ciudad y el territorio. El estudio de este caso concreto nos permite descubrir personajes, relaciones casuales y hallazgos que se despliegan a lo largo del texto. La historia del cementerio de San Michele es también la crónica de la transformación de la ciudad de Venecia y su Laguna. Interpretando este concurso como un instrumento de investigación, el objetivo del artículo es el de comprender la realidad contemporánea de la arquitectura funeraria a través de la isla de San Michele, Venecia, y las propuestas finalistas de Carlos Ferrater, Enric Miralles y David Chipperfield. Una historia bajo la cual se vislumbran claves que nos sirven para reflexionar acerca del cementerio contemporáneo, la ciudad y el territorio. SUMMARY The cemetery is one of the most profound and metaphorical kinds of architecture. The competition for the extension of the San Michele Cemetery, called in 1998 by the Venice municipal administration, is an excellent testing ground on which to analyse the historical context surrounding this type of architecture, and its relationship with the city and the region. The study of this particular case allows us to uncover characters, casual relationships and findings that unfold throughout the text. The history of the San Michele cemetery is also the chronicle of the transformation of the city of Venice and its Lagoon. Interpreting this competition as a research tool, the aim of the paper is to understand the contemporary reality of funerary architecture through the island of San Michele, Venice, and the finalist proposals of Carlos Ferrater, Enric Miralles and David
Quantum teleportation and Kerr-Newman spacetime
Institute of Scientific and Technical Information of China (English)
Ge Xian-Hui; Shen You-Gen
2005-01-01
We consider the teleportation in the background of Kerr-Newman spacetime. Because of the Hawking effect, the fidelity of the teleportation is reduced. The results also show the fidelity is closely related to the mass, charge and rotating velocity of the black hole: high fidelity can be reached for massive, slowly rotating Kerr-Newman black holes.
Poder y resistencia en Michel Foucault
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Reinaldo Giraldo Díaz
2006-01-01
Full Text Available En este artículo se analizan los conceptos de poder y resistencia en las obras del período genealógico de Michel Foucault, es decir, después de El orden del discurso, texto programático y hasta el primer volumen de Historia de la Sexualidad. La voluntad de saber. El artículo realiza sobre todo una elaboración de las concepciones de Foucault sobre el poder y la resistencia en las sociedades disciplinarias y en las sociedades de control. Contrario a lo que sostienen los críticos de Foucault, en este artículo se considera que la resistencia no es negativa, ni reactiva. Nuestra hipótesis de trabajo es que para el pensador francés la resistencia es creativa, productiva y anterior al poder.
Kerr-CFT and gravitational perturbations
International Nuclear Information System (INIS)
Dias, Oscar J.C.; Reall, Harvey S.; Santos, Jorge E.
2009-01-01
Motivated by the Kerr-CFT conjecture, we investigate perturbations of the near-horizon extreme Kerr spacetime. The Teukolsky equation for a massless field of arbitrary spin is solved. Solutions fall into two classes: normal modes and traveling waves. Imposing suitable (outgoing) boundary conditions, we find that there are no unstable modes. The explicit form of metric perturbations is obtained using the Hertz potential formalism, and compared with the Kerr-CFT boundary conditions. The energy and angular momentum associated with scalar field and gravitational normal modes are calculated. The energy is positive in all cases. The behaviour of second order perturbations is discussed.
Kerr scattering coefficients via isomonodromy
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Cunha, Bruno Carneiro da [Departamento de Física, Universidade Federal de Pernambuco,50670-901, Recife, Pernambuco (Brazil); Novaes, Fábio [International Institute of Physics, Federal University of Rio Grande do Norte,Av. Odilon Gomes de Lima 1722, Capim Macio, Natal-RN 59078-400 (Brazil)
2015-11-23
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 σ between the inner and the outer horizons. Using the isomonodromy flow, we calculate σ exactly in terms of the Painlevé V τ-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 Painlevé V τ-function to Liouville irregular conformal blocks to claim that this scattering problem is solved in the combinatorial sense, with known expressions for the τ-function near the critical points.
Michel Houellebecq : un homme, une (soumission
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Marc Smeets
2015-12-01
Full Text Available Michel Houellebecq, l’auteur le plus controversé de la littérature française contemporaine, semble s’astreindre à une seule et unique mission : celle d’être « vrai » à n’importe quel prix. Observateur et peintre de la société actuelle dans tous ses états, l’auteur de Soumission s’inscrit dans une tradition littéraire qui remonte au XIXe siècle, prolongeant ainsi les fictions de Balzac, de Zola et de Huysmans. De ses prédécesseurs Houellebecq hérite d’un certain goût pour la controverse, talent qui fait naturellement la pluie et le beau temps dans la presse. Le rôle que jouent la documentation et la figure du célibataire permet de situer l’écrivain dans le sillage de la tradition réalistico-naturaliste.
Michel Houellebecq and the International Sexual Economy
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Douglas Morrey
2004-01-01
Full Text Available This paper explores the notion of an ‘international sexual economy’ in the work of the French writer Michel Houellebecq, and particularly his latest novel, Plateforme (2001. Houellebecq suggests that, since westerners no longer have the time or the inclination to sleep with each other, and since those in the third world have nothing to sell but their bodies, the exchange of cash for sex on a truly international scale is likely to represent the most lucrative sector of the global economy in the coming century. Whilst acknowledging the objections to this idea, the paper shows how it is based in a serious analysis of global capitalism which has something in common with the theoretical work of Jean-François Lyotard, in terms of both the postmodern and the libidinal economies. The paper further suggests that the virulent anti-psychologism of Houellebecq’s often brutal worldview implies a (largely undeclared kinship with Friedrich Nietzsche. Finally, it offers an analysis of the ironic narrative strategies in Plateforme that are interpreted as the consequence of trying to criticize the cultural economy without being able to position oneself outside it.
Words of gratitude to Dr. Michel Huguet
International Nuclear Information System (INIS)
Yoshikawa, Masaji
2003-01-01
It is impossible for the Japanese fusion community, in particular for those associated with the ITER Project,to hear about the retirement of Dr. Michel Huguet without a great amount of gratitude, recollections, warm feelings, and the inevitable sadness. He was a first-generation ITER EDA person. Three months after the signing of the ITER EDA Agreement in July 1992, he arrived at the Naka Joint Work Site as Deputy Director of the ITER Central Team and Head of the site and he stayed for more than ten years. The Naka site was for design and technical co-ordination in the areas of magnets, plasma control and heating, plant systems, buildings, etc. Dr. Huguet was considered a highly qualified person to fill the position, since he had been successful as Deputy Director in similar areas in the JET Joint Undertaking. During the ITER EDA he co-ordinated the R and D activities in areas for which the Naka Joint Work Site was responsible. These R and D results permitted the completion of the ITER design in the above areas under his supervision. We thank Dr. Huguet for his achievements and contributions to ITER. He played a crucial role in establishing the convincing scientific and technical basis for ITER implementation. This was only made possible by his broad abilities and his dedication to the cause of fusion in general and ITER in particular
Energy Technology Data Exchange (ETDEWEB)
Bejarano, Cecilia; Guzman, Maria Jose [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Ferraro, Rafael [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)
2015-02-01
Null tetrads are shown to be a valuable tool in teleparallel theories of modified gravity. We use them to prove that Kerr geometry remains a solution for a wide family of f(T) theories of gravity. (orig.)
International Nuclear Information System (INIS)
Bejarano, Cecilia; Guzman, Maria Jose; Ferraro, Rafael
2015-01-01
Null tetrads are shown to be a valuable tool in teleparallel theories of modified gravity. We use them to prove that Kerr geometry remains a solution for a wide family of f(T) theories of gravity. (orig.)
Dressing up a Kerr naked singularity
Energy Technology Data Exchange (ETDEWEB)
Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; Nobili, L [Padua Univ. (Italy). Ist. di Fisica
1979-06-11
The evolution of a naked singularity surrounded by an accreting disk of matter is studied; two kinds of disks are considered: the standard thin-disk model and the thick barytropic model, for several initial conditions. It is shown that any Kerr naked singularity slows down in a finite time to a maximal Kerr black hole. The final mass, the luminosity and the time of evolution of the singularity are evaluated.
Radiating Kerr particle in Einstein universe
International Nuclear Information System (INIS)
Vaidya, P.C.; Patel, L.K.
1989-01-01
A generalized Kerr-NUT type metric is considered in connection with Einstein field equations corresponding to perfect fluid plus a pure radiation field. A general scheme for obtaining the exact solutions of these field equations is developed. Two physically meaningful particular cases are investigated in detail. One gives the field of a radiating Kerr particle embedded in the Einstein universe. The other solution may probably represent a deSitter-like universe pervaded by a pure radiation field. (author). 7 refs
Post-Kerr black hole spectroscopy
Glampedakis, Kostas; Pappas, George; Silva, Hector O.; Berti, Emanuele
2017-09-01
One of the central goals of the newborn field of gravitational wave astronomy is to test gravity in the highly nonlinear, strong field regime characterizing the spacetime of black holes. In particular, "black hole spectroscopy" (the observation and identification of black hole quasinormal mode frequencies in the gravitational wave signal) is expected to become one of the main tools for probing the structure and dynamics of Kerr black holes. In this paper we take a significant step toward that goal by constructing a "post-Kerr" quasinormal mode formalism. The formalism incorporates a parametrized but general perturbative deviation from the Kerr metric and exploits the well-established connection between the properties of the spacetime's circular null geodesics and the fundamental quasinormal mode to provide approximate, eikonal limit formulas for the modes' complex frequencies. The resulting algebraic toolkit can be used in waveform templates for ringing black holes with the purpose of measuring deviations from the Kerr metric. As a first illustrative application of our framework, we consider the Johannsen-Psaltis deformed Kerr metric and compute the resulting deviation in the quasinormal mode frequency relative to the known Kerr result.
Kerr Hollow Quarry Remediation Project
International Nuclear Information System (INIS)
Walker, K.L.
1993-01-01
The Kerr Hollow Quarry is a 3-acre flooded limestone quarry located near the Y-12 Facility on the Oak Ridge Reservation. The quarry was used in the 1940s as a source of construction material for the Department of Energy in Oak Ridge, Tennessee. Its use was discontinued in the early 1950s, and it was allowed to flood with water. The quarry presently has a maximum water depth of approximately 55 ft. During the period between the early 1950s until about 1988, the quarry was used for the treatment and disposal of a variety of materials including water-reactive, alkali metals, shock-sensitive chemicals, and compressed gas cylinders. For some of these materials, the treatment consisted of dropping the vessels containing the materials into the quarry from a high bluff located on one side of the quarry. The vessels were then punctured by gun shot, and the materials were allowed to react with the water and sink to the bottom of the quarry. Very few disposal records exist for the period from 1952 to 1962. The records after that time, from 1962 until 1988, indicate some 50 t of hazardous and nonhazardous materials were disposed of in the quarry. This report documents remediation efforts that have taken place at the quarry beginning in September 1990
International Nuclear Information System (INIS)
Akcay, Sarp; Matzner, Richard A
2011-01-01
It is now widely accepted that the universe as we understand it is accelerating in expansion and fits the de Sitter model rather well. As such, a realistic assumption of black holes must place them on a de Sitter background and not Minkowski as is typically done in general relativity. The most astrophysically relevant black hole is the uncharged, rotating Kerr solution, a member of the more general Kerr-Newman metrics. A generalization of the rotating Kerr black hole to a solution of the Einstein's equation with a cosmological constant Λ was discovered by Carter (1973 Les Astres Occlus ed B DeWitt and C M DeWitt (New York: Gordon and Breach)). It is typically referred to as the Kerr-de Sitter spacetime. Here, we discuss the horizon structure of this spacetime and its dependence on Λ. We recall that in a Λ > 0 universe, the term 'extremal black hole' refers to a black hole with angular momentum J > M 2 . We obtain explicit numerical results for the black hole's maximal spin value and get a distribution of admissible Kerr holes in the (Λ, spin) parameter space. We look at the conformal structure of the extended spacetime and the embedding of the 3-geometry of the spatial hypersurfaces. In analogy with Reissner-Nordstroem-de Sitter spacetime, in particular by considering the Kerr-de Sitter causal structure as a distortion of the Reissner-Nordstroem-de Sitter one, we show that spatial sections of the extended spacetime are 3-spheres containing two-dimensional topologically spherical sections of the horizons of Kerr holes at the poles. Depending on how a t = constant 3-space is defined, these holes may be seen as black or white holes (four possible combinations).
Dirac equation in Kerr space-time
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Iyer, B R; Kumar, Arvind [Bombay Univ. (India). Dept. of Physics
1976-06-01
The weak-field low-velocity approximation of Dirac equation in Kerr space-time is investigated. The interaction terms admit of an interpretation in terms of a 'dipole-dipole' interaction in addition to coupling of spin with the angular momentum of the rotating source. The gravitational gyro-factor for spin is identified. The charged case (Kerr-Newman) is studied using minimal prescription for electromagnetic coupling in the locally intertial frame and to the leading order the standard electromagnetic gyro-factor is retrieved. A first order perturbation calculation of the shift of the Schwarzchild energy level yields the main interesting result of this work: the anomalous Zeeman splitting of the energy level of a Dirac particle in Kerr metric.
Appearance of Keplerian discs orbiting Kerr superspinars
Energy Technology Data Exchange (ETDEWEB)
Stuchlik, Zdenek; Schee, Jan, E-mail: zdenek.stuchlik@fpf.slu.c, E-mail: jan.schee@fpf.slu.c [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo nam. 13, Opava (Czech Republic)
2010-11-07
We study optical phenomena related to the appearance of Keplerian accretion discs orbiting Kerr superspinars predicted by string theory. The superspinar exterior is described by standard Kerr naked singularity geometry breaking the black hole limit on the internal angular momentum (spin). We construct local photon escape cones for a variety of orbiting sources that enable us to determine the superspinars silhouette in the case of distant observers. We show that the superspinar silhouette depends strongly on the assumed edge where the external Kerr spacetime is joined to the internal spacetime governed by string theory and significantly differs from the black hole silhouette. The appearance of the accretion disc is strongly dependent on the value of the superspinar spin in both their shape and frequency shift profile. Apparent extension of the disc grows significantly with the growing spin, while the frequency shift grows with the descending spin. This behaviour differs substantially from the appearance of discs orbiting black holes enabling thus, at least in principle, to distinguish clearly the Kerr superspinars and black holes. In vicinity of a Kerr superspinar the non-escaped photons have to be separated to those captured by the superspinar and those being trapped in its strong gravitational field leading to self-illumination of the disc that could even influence its structure and cause self-reflection effect of radiation of the disc. The amount of trapped photons grows with descending superspinar spin. We thus can expect significant self-illumination effects in the field of Kerr superspinars with near-extreme spin a {approx} 1.
Measurement of the Michel Parameters in Leptonic Tau Decays
Ackerstaff, K.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bohme, J.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Hargrove, C.K.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kyberd, P.; Lafferty, G.D.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schorner, T.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Tafirout, R.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Vikas, P.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.
1999-01-01
The Michel parameters of the leptonic tau decays are measured using the OPAL detector at LEP. The Michel parameters are extracted from the energy spectra of the charged decay leptons and from their energy-energy correlations. A new method involving a global likelihood fit of Monte Carlo generated events with complete detector simulation and background treatment has been applied to the data recorded at center-of-mass energies close to sqrt(s) = M(Z) corresponding to an integrated luminosity of 155 pb-1 during the years 1990 to 1995. If e-mu universality is assumed and inferring the tau polarization from neutral current data, the measured Michel parameters are extracted. Limits on non-standard coupling constants and on the masses of new gauge bosons are obtained. The results are in agreement with the V-A prediction of the Standard Model.
Finite escape fraction for ultrahigh energy collisions around Kerr ...
Indian Academy of Sciences (India)
Abstract. We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location r = M around the Kerr naked ...
Finite escape fraction for ultrahigh energy collisions around Kerr
Indian Academy of Sciences (India)
We investigate the issue of observability of high-energy collisions around Kerr naked singularity and show that results are in contrast with the Kerr black hole case. We had shown that it would be possible to have ultrahigh energy collisions between the particles close to the location = M around the Kerr naked singularity if ...
Tidal interactions with Kerr black holes
International Nuclear Information System (INIS)
Hiscock, W.A.
1977-01-01
The tidal deformation of an extended test body falling with zero angular momentum into a Kerr black hole is calculated. Numerical results for infall along the symmetry axis and in the equatorial plane of the black hole are presented for a range of values of a, the specific angular momentum of the black hole. Estimates of the tidal contribution to the gravitational radiation are also given. The tidal contribution in equatorial infall into a maximally rotating Kerr black hole may be of the same order as the center-of-mass contribution to the gravitational radiation
Fast plunges into Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Hadar, Shahar [Racah Institute of Physics, Hebrew University,Jerusalem 91904 (Israel); Porfyriadis, Achilleas P.; Strominger, Andrew [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States)
2015-07-15
Most extreme-mass-ratio-inspirals of small compact objects into supermassive black holes end with a fast plunge from an eccentric last stable orbit. For rapidly rotating black holes such fast plunges may be studied in the context of the Kerr/CFT correspondence because they occur in the near-horizon region where dynamics are governed by the infinite dimensional conformal symmetry. In this paper we use conformal transformations to analytically solve for the radiation emitted from fast plunges into near-extreme Kerr black holes. We find perfect agreement between the gravity and CFT computations.
Normal-dispersion microresonator Kerr frequency combs
Directory of Open Access Journals (Sweden)
Xue Xiaoxiao
2016-06-01
Full Text Available Optical microresonator-based Kerr frequency comb generation has developed into a hot research area in the past decade. Microresonator combs are promising for portable applications due to their potential for chip-level integration and low power consumption. According to the group velocity dispersion of the microresonator employed, research in this field may be classified into two categories: the anomalous dispersion regime and the normal dispersion regime. In this paper, we discuss the physics of Kerr comb generation in the normal dispersion regime and review recent experimental advances. The potential advantages and future directions of normal dispersion combs are also discussed.
Some new radiating Kerr-Newman solutions
International Nuclear Information System (INIS)
Patel, L.K.; Singh, Tajinder; Koppar, S.S.
1991-01-01
Three exact non-static solutions of Einstein-Maxwell equations corresponding to a field of flowing null radiation plus an electromagnetic field are presented. These solutions are non-static generalizations of the well known Kerr-Newman solution. The current vector is null in all the three solutions. These solutions are the electromagnetic generalizations of the three generalized radiating Kerr solutions discussed by Vaidya and Patel. The solutions discussed here describe the exterior gravitational fields of rotating radiating charged bodies. Many known solutions are derived as particular cases. (author). 12 refs
Innermost stable circular orbit of Kerr-MOG black hole
Energy Technology Data Exchange (ETDEWEB)
Lee, Hyun-Chul; Han, Yong-Jin [Soonchunhyang University, Department of Physics, Asan (Korea, Republic of)
2017-10-15
We study the innermost stable circular orbit (ISCO) of the metric of the Kerr black hole in modified gravity (Kerr-MOG black hole), which is one of the exact solutions of the field equation of modified gravity in the strong gravity regime. The Kerr-MOG metric is constructed; it is the commonly known Kerr metric in Boyer-Lindquist coordinates by adding a repulsive term like the Yukawa force, which is explained in quantum gravity. In this paper, we numerically calculate the circular orbit of a photon and the ISCO of a test particle of Kerr-MOG black holes. (orig.)
New entropy formula for Kerr black holes
Directory of Open Access Journals (Sweden)
González Hernán A.
2018-01-01
Full Text Available We introduce a new entropy formula for Kerr black holes inspired by recent results for 3-dimensional black holes and cosmologies with soft Heisenberg hair. We show that also Kerr–Taub–NUT black holes obey the same formula.
Kerr black holes with scalar hair.
Herdeiro, Carlos A R; Radu, Eugen
2014-06-06
We present a family of solutions of Einstein's gravity minimally coupled to a complex, massive scalar field, describing asymptotically flat, spinning black holes with scalar hair and a regular horizon. These hairy black holes (HBHs) are supported by rotation and have no static limit. Besides mass M and angular momentum J, they carry a conserved, continuous Noether charge Q measuring the scalar hair. HBHs branch off from the Kerr metric at the threshold of the superradiant instability and reduce to spinning boson stars in the limit of vanishing horizon area. They overlap with Kerr black holes for a set of (M, J) values. A single Killing vector field preserves the solutions, tangent to the null geodesic generators of the event horizon. HBHs can exhibit sharp physical differences when compared to the Kerr solution, such as J/M^{2}>1, a quadrupole moment larger than J^{2}/M, and a larger orbital angular velocity at the innermost stable circular orbit. Families of HBHs connected to the Kerr geometry should exist in scalar (and other) models with more general self-interactions.
Modulational instability in nonlocal nonlinear Kerr media
DEFF Research Database (Denmark)
Krolikowski, Wieslaw; Bang, Ole; Juul Rasmussen, Jens
2001-01-01
We study modulational instability (MI) of plane waves in nonlocal nonlinear Kerr media. For a focusing nonlinearity we show that, although the nonlocality tends to suppress MI, it can never remove it completely, irrespective of the particular profile of the nonlocal response function. For a defoc...
Michel Houellebecq uusi inimeksitetsi territooriume kaardistamas / Triinu Tamm
Tamm, Triinu
2010-01-01
Prantsuse kirjaniku Michel Houellebecq uuest romaanist "Kaart ja territoorium" ("La carte et le territoire", "Flammarion"), mille ilmumine on tekitanud palju poleemikat ja püsib mitme maineka kirjandusauhinna pretendentide seas, muuhulgas juba teist vooru Goncourt'i auhinda püüdvate romaanide nimekirjas
Editorial | Michell | Southern African Journal of Critical Care
African Journals Online (AJOL)
Southern African Journal of Critical Care. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 32, No 2 (2016) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Editorial. Lance Michell. Abstract. Care or burn in ...
An architect for mental health: an appreciation of Michele Tansella.
Thornicroft, Graham
2017-06-01
Michele Tansella, Professor of Psychiatry at the University of Verona, died in 2015. This editorial pays tribute to his contributions to scholarship in the field of psychiatric epidemiology and health service research, and to his highly effective efforts to improve mental healthcare, locally, nationally and internationally. © The Royal College of Psychiatrists 2017.
Analysis of the normal optical, Michel and molecular potentials on ...
Indian Academy of Sciences (India)
6. — journal of. June 2016 physics pp. 1275–1286. Analysis of the normal ... the levels are obtained for the three optical potentials to estimate the quality ... The experimental angular distribution data for the 40Ca(6Li, d)44Ti reaction .... analysed using the normal optical, Michel and molecular potentials within the framework.
Directory of Open Access Journals (Sweden)
Alexander Burinskii
2013-01-01
Full Text Available The 4D Kerr geometry displays many wonderful relations with quantum world and, in particular, with superstring theory. The lightlike structure of fields near the Kerr singular ring is similar to the structure of Sen solution for a closed heterotic string. Another string, open and complex, appears in the complex representation of the Kerr geometry initiated by Newman. Combination of these strings forms a membrane source of the Kerr geometry which is parallel to the structure of M-theory. In this paper we give one more evidence of this relationship, emergence of the Calabi-Yau twofold (K3 surface in twistorial structure of the Kerr geometry as a consequence of the Kerr theorem. Finally, we indicate that the Kerr stringy system may correspond to a complex embedding of the critical N = 2 superstring.
Kerr black holes are not fragile
Energy Technology Data Exchange (ETDEWEB)
McInnes, Brett, E-mail: matmcinn@nus.edu.sg [Centro de Estudios Cientificos (CECs), Valdivia (Chile); National University of Singapore (Singapore)
2012-04-21
Certain AdS black holes are 'fragile', in the sense that, if they are deformed excessively, they become unstable to a fundamental non-perturbative stringy effect analogous to Schwinger pair-production [of branes]. Near-extremal topologically spherical AdS-Kerr black holes, which are natural candidates for string-theoretic models of the very rapidly rotating black holes that have actually been observed to exist, do represent a very drastic deformation of the AdS-Schwarzschild geometry. One therefore has strong reason to fear that these objects might be 'fragile', which in turn could mean that asymptotically flat rapidly rotating black holes might be fragile in string theory. Here we show that this does not happen: despite the severe deformation implied by near-extremal angular momenta, brane pair-production around topologically spherical AdS-Kerr-Newman black holes is always suppressed.
Asymptotic twistor theory and the Kerr theorem
International Nuclear Information System (INIS)
Newman, Ezra T
2006-01-01
We first review asymptotic twistor theory with its real subspace of null asymptotic twistors: a five-dimensional CR manifold. This is followed by a description of the Kerr theorem (the identification of shear-free null congruences, in Minkowski space, with the zeros of holomorphic functions of three variables) and an asymptotic version of the Kerr theorem that produces regular asymptotically shear-free null geodesic congruences in arbitrary asymptotically flat Einstein or Einstein-Maxwell spacetimes. A surprising aspect of this work is the role played by analytic curves in H-space, each curve generating an asymptotically flat null geodesic congruence. Also there is a discussion of the physical space realizations of the two associated five- and three-dimensional CR manifolds
Stabilized vortices in layered Kerr media
International Nuclear Information System (INIS)
Montesinos, Gaspar D.; Perez-Garcia, Victor M.; Michinel, Humberto; Salgueiro, Jose R.
2005-01-01
In this paper, we demonstrate the possibility of stabilizing beams with angular momentum propagating in Kerr media against filamentation and collapse. Very long propagation distances can be achieved by combining the choice of an appropriate layered medium with alternating focusing and defocusing nonlinearities with the presence of an incoherent guiding beam which is itself stabilized in this medium. The applicability of the results to the field of matter waves is also discussed
An outline of ethics on the work of Michel Foucault
DEFF Research Database (Denmark)
Christensen, Gerd
An outline of ethics on the work of Michel Foucault The French philosopher Michel Foucault is well known for his critical thinking and for his genealogies of the human subject. In these analyzes power and knowledge (power-knowledge) plays a decisive role. For Foucault power-knowledge is the very...... (Kelly (edt.) 1994). Nevertheless, Foucault ended his academic career discussing ethics in the form of ethos (Foucault 1994). In this form his ethical project approaches an aesthetic project in the form of the individual’s self-creation. In my presentation I will introduce Foucault’s concept of ethos...... and discuss the possibilities and limitations in this position. In addition, I will argue that his insistently critical stance and power-knowledge concept can be considered as an ethical stance different from both deontology and utilitarism. As such, it could have an important impact on the practice...
Poder y subjetividad en Michel Foucault: traslaciones, modificaciones, ambivalencias
Directory of Open Access Journals (Sweden)
Lorena Acosta Iglesias
2016-05-01
Full Text Available The goal of this article is to measure the translations, modifications and ambivalences of the relationship between power and subjectivity in two land-marks of the philosophical production of Michel Foucault: Discipline and punish (1975, and The birth of biopolitics (1978-79. In this way, we will try to extract the foucaultian procedure some clues to a current materialistic approach of this relation at a time of maximum social dissolution.
Post Media Literacy: Menyaksikan Kuasa Media Bersama Michel Foucault
Iswandi Syahputra
2017-01-01
This article would like to present Michel Foucault’s idea concerning Knowledge and Power in media industry. As a contemporary intellectual, Foucault’s thought has a unique style of postmodernism. His thought had gone beyond traditional critical theory whose trying to disclose the relation of power and economic behind the ideology of media. Foucault’s thought had given new perspective in understanding how the media produce truth under tightly control process into something that seems normal. ...
The Kerr geometry, complex world lines and hyperbolic strings
International Nuclear Information System (INIS)
Burinskii, A.Ya.
1994-01-01
In the Lind-Newman representation the Kerr geometry is created by a source moving along an analytical complex world line. An equivalence of the complex world line and complex (hyperbolic) string is considered. Therefore the hyperbolic string may play the role of the complex source of the Kerr geometry. The Kerr solution with the complex string source acquires Regge behavior of the angular momentum. (orig.)
Critical exponents of extremal Kerr perturbations
Gralla, Samuel E.; Zimmerman, Peter
2018-05-01
We show that scalar, electromagnetic, and gravitational perturbations of extremal Kerr black holes are asymptotically self-similar under the near-horizon, late-time scaling symmetry of the background metric. This accounts for the Aretakis instability (growth of transverse derivatives) as a critical phenomenon associated with the emergent symmetry. We compute the critical exponent of each mode, which is equivalent to its decay rate. It follows from symmetry arguments that, despite the growth of transverse derivatives, all generally covariant scalar quantities decay to zero.
Bejarano, Cecilia; Ferraro, Rafael; Guzmán, María José
2014-01-01
Null tetrads are shown to be a valuable tool in teleparallel theories of modified gravity. We use them to prove that Kerr geometry remains a solution for a wide family of theories of gravity. Fil: Bejarano, Cecilia Soledad. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Fí...
Terahertz-induced Kerr effect in amorphous chalcogenide glasses
DEFF Research Database (Denmark)
Zalkovskij, Maksim; Strikwerda, Andrew; Iwaszczuk, Krzysztof
2013-01-01
We have investigated the terahertz-induced third-order (Kerr) nonlinear optical properties of the amorphous chalcogenide glasses As2S3 and As2Se3. Chalcogenide glasses are known for their high optical Kerr nonlinearities which can be several hundred times greater than those of fused silica. We use...
El concepto de heterotopía en Michel Foucault
Directory of Open Access Journals (Sweden)
María Cristina Toro Zambrano
2018-02-01
Full Text Available El análisis del concepto de heterotopía, explicado por Michel Foucault en su conferencia “Los espacios otros”, tiene importancia dentro del proyecto general de una historia crítica del pensamiento. Las heterotopías pertenecen a un tipo específico de espacio, que tiene dentro de sí poderes, fuerzas, ideas, regularidades o discontinuidades, se pueden clasificar según el tiempo o el lugar al que pertenecen y abren la posibilidad de crear nuevos espacios con sus propias lógicas.
Determination of the Michel parameter in tau decay
International Nuclear Information System (INIS)
Albrecht, H.; Ehrlichmann, H.; Harder, G.; Krueger, A.; Nau, A.; Nilsson, A.W.; Nippe, A.; Oest, T.; Reidenbach, M.; Schaefer, M.; Schmidt-Parzefall, W.; Schroeder, H.; Schulz, H.D.; Sefkow, F.; Wurth, R.; Appuhn, R.D.; Drescher, A.; Hast, C.; Herrera, G.; Kolanoski, H.; Lange, A.; Lindner, A.; Mankel, R.; Scheck, H.; Schieber, M.; Schweda, G.; Spaan, B.; Walther, A.; Wegener, D.; Britton, D.I.; MacFarlane, D.B.; McLean, K.W.; Patel, P.M.; Tsipolitis, G.; Tzamariudaki, K.; Charlesworth, C.E.K.; Krieger, P.; Kutschke, R.; Orr, R.S.; Parsons, J.A.; Prentice, J.D.; Seidel, S.C.; Yoon, T.S.; Edwards, K.W.; Kapitza, H.; Ruf, T.; Schael, S.; Schubert, K.R.; Strahl, K.; Waldi, R.; Weseler, S.
1990-01-01
Using the ARGUS detector at the DORIS II e + e - storage ring we have studied the electron and muon energy spectra in τ - →e - νanti ν and τ - →μ - νanti ν. The measured value of the Michel parameter, ρ=0.742±0.035±0.020, is in good agreement with a standard V-A coupling at the τ-ν τ -W vertex. Pure V, A and V+A couplings are completely excluded by this measurement. Upper limits have been obtained for two-body tau decays, including final states with a Goldstone boson. (orig.)
Michel Foucault’s ‘Apology’ for Neoliberalism
DEFF Research Database (Denmark)
Dean, Mitchell
2014-01-01
Lecture delivered at the British Library on the 30th anniversary of the death of Michel Foucault, June 25, 2014. This lecture evaluates the claim made by one of his closest followers, François Ewald, that Foucault offered an apology for neoliberalism, particularly of the American school represented......-democratic take-up of neoliberal thought. It indicates three limitations of his thought: the problem of state ‘veridiction’; the question of inequality; and the concept of the economy. It also indicates how these might be addressed within a general appreciation of his thought....
[Michel Foucault and the persistence of psychiatric power].
Caponi, Sandra
2009-01-01
This article aims studying the course held by Michel Foucault at the Collège de France in 1973-1974. The records of this course were published in 2003 under the name ' Psychiatric power' . The objective was to compare the different ways in which Foucault analyzes the question of madness in ' Psychiatric power' and in ' History of Madness in the Classical Age' (1961). It is a comparative study about the different ways of analyzing madness developed by Michel Foucault during the archeological and genealogic periods of his work. The absence of the body; binary diagnosis; the description of the surface of symptoms; the classification of diseases more similar to the botanical classification than to pathology; the process of cure directly linked to restitution of behaviors and moral values; as well as the over-power of the psychiatrist, seem to speak about the persistence of an old model of power, a pre-modern and pre-capitalist model, a residue of the old sovereign power.
Hawking radiation as tunneling from the Kerr and Kerr-Newman black holes
International Nuclear Information System (INIS)
Jiang Qingqan; Wu Shuangqing; Cai Xu
2006-01-01
Recent work, which treats the Hawking radiation as a semiclassical tunneling process at the horizon of the Schwarzschild and Reissner-Nordstroem spacetimes, indicates that the exact radiant spectrum is no longer pure thermal after considering the black hole background as dynamical and the conservation of energy. In this paper, we extend the method to investigate Hawking radiation as massless particles tunneling across the event horizon of the Kerr black hole and that of charged particles from the Kerr-Newman black hole by taking into account the energy conservation, the angular momentum conservation, and the electric charge conservation. Our results show that when self-gravitation is considered, the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum, but is consistent with an underlying unitary theory
The superradiant instability regime of the spinning Kerr black hole
Hod, Shahar
2016-07-01
Spinning Kerr black holes are known to be superradiantly unstable to massive scalar perturbations. We here prove that the instability regime of the composed Kerr-black-hole-massive-scalar-field system is bounded from above by the dimensionless inequality Mμ r+ is the dimensionless ratio between the horizon radii of the black hole. It is further shown that this analytically derived upper bound on the superradiant instability regime of the spinning Kerr black hole agrees with recent numerical computations of the instability resonance spectrum.
Scaling dimensions in hidden Kerr/CFT correspondence
International Nuclear Information System (INIS)
Lowe, David A.; Messamah, Ilies; Skanata, Antun
2011-01-01
It has been proposed that a hidden conformal field theory (CFT) governs the dynamics of low frequency scattering in a general Kerr black hole background. We further investigate this correspondence by mapping higher order corrections to the massless wave equations in a Kerr background to an expansion within the CFT in terms of higher dimension operators. This implies the presence of infinite towers of CFT primary operators with positive conformal dimensions compatible with unitarity. The exact Kerr background softly breaks the conformal symmetry and the scaling dimensions of these operators run with frequency. The scale-invariant fixed point is dual to a degenerate case of flat spacetime.
Kerr metric in the deSitter background
International Nuclear Information System (INIS)
Vaidya, P.C.
1984-01-01
In addition to the Kerr metric with cosmological constant Λ several other metrics are presented giving a Kerr-like solution of Einstein's equations in the background of deSitter universe. A new metric of what may be termed as rotating deSitter space-time devoid of matter but containing null fluid with twisting null rays, has been presented. This metric reduces to the standard deSitter metric when the twist in the rays vanishes. Kerr metric in this background is the immediate generalization of Schwarzschild's exterior metric with cosmological constant. (author)
Equatorial circular motion in Kerr spacetime
International Nuclear Information System (INIS)
Pugliese, Daniela; Quevedo, Hernando; Ruffini, Remo
2011-01-01
We analyze the properties of circular orbits of test particles on the equatorial plane of a rotating central mass whose gravitational field is described by the Kerr spacetime. For rotating black holes and naked singularities we explore all the spatial regions where circular orbits can exist and analyze the behavior of the energy and the angular momentum of the corresponding test particles. In particular, we find all the radii at which a test particle can have zero angular momentum due to the repulsive gravity effects generated by naked singularities. We classify all the stability zones of circular orbits. It is shown that the geometric structure of the stability zones of black holes is completely different from that of naked singularities.
Post Media Literacy: Menyaksikan Kuasa Media Bersama Michel Foucault
Directory of Open Access Journals (Sweden)
Iswandi Syahputra
2017-01-01
Full Text Available This article would like to present Michel Foucault’s idea concerning Knowledge and Power in media industry. As a contemporary intellectual, Foucault’s thought has a unique style of postmodernism. His thought had gone beyond traditional critical theory whose trying to disclose the relation of power and economic behind the ideology of media. Foucault’s thought had given new perspective in understanding how the media produce truth under tightly control process into something that seems normal. With the assumption of media has the power to create mass culture, which has to be studied critically by media literacy approach, Foucault’s thought had given new space of discursive. An alternative thought on how to estimate the work of mass media as supervisor of truth and creator of information trough normalization practice.
Symmetries in nature the scientific heritage of Louis Michel
Todorov, Ivan; Zhilinskii, Boris
2014-01-01
Reflecting the oeuvre of “a man of two cultures: the culture of pure mathematics and the culture of theoretical physics” (in the words of his long time friend and co-author, Kameshwar Wali), this volume is centred around the notion of symmetry and its breaking. Starting with particle physics, the content proceeds to symmetries of matter, defects, and crystals. The mathematics of group extensions, non-linear group action, critical orbits and phase transitions is developed along the way. The symmetry principles and general mathematical tools provide unity in the treatment of different topics. The papers and lecture notes are preceded by a lively biography of Louis Michel and a commentary that relates his selected works both to the physics of his time and to contemporary trends. This book should be of interest to theoretical physicists, chemists, applied mathematicians and historians of science, and is accessible to graduate (and advanced undergraduate) students.
Introduction to Louis Michel's lattice geometry through group action
Zhilinskii, Boris
2015-01-01
Group action analysis developed and applied mainly by Louis Michel to the study of N-dimensional periodic lattices is the central subject of the book. Different basic mathematical tools currently used for the description of lattice geometry are introduced and illustrated through applications to crystal structures in two- and three-dimensional space, to abstract multi-dimensional lattices and to lattices associated with integrable dynamical systems. Starting from general Delone sets the authors turn to different symmetry and topological classifications including explicit construction of orbifolds for two- and three-dimensional point and space groups. Voronoï and Delone cells together with positive quadratic forms and lattice description by root systems are introduced to demonstrate alternative approaches to lattice geometry study. Zonotopes and zonohedral families of 2-, 3-, 4-, 5-dimensional lattices are explicitly visualized using graph theory approach. Along with crystallographic applications, qualitative ...
STS-93 M.S. Michel Tognini in white room
1999-01-01
STS-93 Mission Specialist Michel Tognini of France is checked out by white room closeout crew members before entering the orbiter Columbia. Tognini is with the Centre National d'Etudes Spatiales (CNES). The white room is an environmental chamber at the end of the orbiter access arm that provides entry to the orbiter crew compartment. STS-93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. After Space Shuttle Columbia's July 20 and 22 launch attempts were scrubbed, the launch was again rescheduled for Friday, July 23, at 12:24 a.m. EDT. The target landing date is July 27 at 11:20 p.m. EDT.
On the (non-)optimality of Michell structures
DEFF Research Database (Denmark)
Sigmund, Ole; Aage, Niels; Andreassen, Erik
2016-01-01
Optimal analytical Michell frame structures have been extensively used as benchmark examples in topology optimization, including truss, frame, homogenization, density and level-set based approaches. However, as we will point out, partly the interpretation of Michell’s structural continua...... as discrete frame structures is not accurate and partly, it turns out that limiting structural topology to frame-like structures is a rather severe design restriction and results in structures that are quite far from being stiffness optimal. The paper discusses the interpretation of Michell’s theory...... in the context of numerical topology optimization and compares various topology optimization results obtained with the frame restriction to cases with no design restrictions. For all examples considered, the true stiffness optimal structures are composed of sheets (2D) or closed-walled shell structures (3D...
The zero mass limit of Kerr and Kerr-(anti-)de-Sitter space-times: exact solutions and wormholes
Birkandan, T.; Hortaçsu, M.
2018-03-01
Heun-type exact solutions emerge for both the radial and the angular equations for the case of a scalar particle coupled to the zero mass limit of both the Kerr and Kerr-(anti)de-Sitter spacetime. Since any type D metric has Heun-type solutions, it is interesting that this property is retained in the zero mass case. This work further refutes the claims that M going to zero limit of the Kerr metric is both locally and globally the same as the Minkowski metric.
Small Kerr-anti-de Sitter black holes are unstable
International Nuclear Information System (INIS)
Cardoso, Vitor; Dias, Oscar J.C.
2004-01-01
Superradiance in black hole spacetimes can trigger instabilities. Here we show that, due to superradiance, small Kerr-anti-de Sitter black holes are unstable. Our demonstration uses a matching procedure, in a long wavelength approximation
Non-extremal Kerr black holes as particle accelerators
Gao, Sijie; Zhong, Changchun
2011-01-01
It has been shown that extremal Kerr black holes can be used as particle accelerators and arbitrarily high energy may be obtained near the event horizon. We study particle collisions near the event horizon (outer horizon) and Cauchy horizon (inner horizon) of a non-extremal Kerr black hole. Firstly, we provide a general proof showing that particles cannot collide with arbitrarily high energies at the outter horizon. Secondly, we show that ultraenergetic collisions can occur near the inner hor...
Spatial Discrete Soliton in Two dimensional with Kerr medium
International Nuclear Information System (INIS)
Aghdami, M.; Mostafavi, D.; Mokhtari, F.; Keradmand, R.
2012-01-01
In this theoretical work propagation of the Gaussian beam through a two dimensional waveguides array is numerically investigated, in which each waveguide contains medium with Kerr nonlinearity considering coupling to vertical, horizontal and diagonal neighbor through light electric field. Different values of intensity, nonlinear coefficient Kerr and Gaussian beam width of incident Gaussian beam are examined and finally suitable parameters for providing central spatial solitons are obtained.
International Nuclear Information System (INIS)
Carter, B.; McLenaghan, R.G.
1982-01-01
It is shown how previous general formulae for the separated radial and angular parts of the massive, charged scalar (Klein, Gordon) wave equation on one hand, and of the zero mass, neutral, but higher spin (neutrino, electromagnetic and gravitational) wave equations on the other hand may be combined in a more general formula which also covers the case of the full massive charged Dirac equation in a Kerr or Kerr-Newman background space. (Auth.)
Radiation transport around Kerr black holes
Schnittman, Jeremy David
This Thesis describes the basic framework of a relativistic ray-tracing code for analyzing accretion processes around Kerr black holes. We begin in Chapter 1 with a brief historical summary of the major advances in black hole astrophysics over the past few decades. In Chapter 2 we present a detailed description of the ray-tracing code, which can be used to calculate the transfer function between the plane of the accretion disk and the detector plane, an important tool for modeling relativistically broadened emission lines. Observations from the Rossi X-Ray Timing Explorer have shown the existence of high frequency quasi-periodic oscillations (HFQPOs) in a number of black hole binary systems. In Chapter 3, we employ a simple "hot spot" model to explain the position and amplitude of these HFQPO peaks. The power spectrum of the periodic X-ray light curve consists of multiple peaks located at integral combinations of the black hole coordinate frequencies, with the relative amplitude of each peak determined by the orbital inclination, eccentricity, and hot spot arc length. In Chapter 4, we introduce additional features to the model to explain the broadening of the QPO peaks as well as the damping of higher frequency harmonics in the power spectrum. The complete model is used to fit the power spectra observed in XTE J1550-564, giving confidence limits on each of the model parameters. In Chapter 5 we present a description of the structure of a relativistic alpha- disk around a Kerr black hole. Given the surface temperature of the disk, the observed spectrum is calculated using the transfer function mentioned above. The features of this modified thermal spectrum may be used to infer the physical properties of the accretion disk and the central black hole. In Chapter 6 we develop a Monte Carlo code to calculate the detailed propagation of photons from a hot spot emitter scattering through a corona surrounding the black hole. The coronal scattering has two major observable
Viscous shear in the Kerr metric
International Nuclear Information System (INIS)
Anderson, M.R.; Lemos, J.P.S.
1988-01-01
Models of viscous flows on to black holes commonly assume a zero-torque boundary condition at the radius of the last stable Keplerian orbit. It is here shown that this condition is wrong. The viscous torque is generally non-zero at both the last stable orbit and the horizon itself. The existence of a non-zero viscous torque at the horizon does not require the transfer of energy or angular momentum across any spacelike distance, and so does not violate causality. Further, in comparison with the viscous torque in the distant, Newtonian regime, the viscous torque on the horizon is often reversed, so that angular momentum is viscously advected inwards rather than outwards. This phenomenon is first suggested by an analysis of the quasi-stationary case, and then demonstrated explicitly for a series of cold, dynamical flows which fall freely from the last stable orbit in the Schwarzschild and Kerr metrics. In the steady flows constructed here, the net torque on the hole is always directed in the usual sense; any reversal in the viscous torque is offset by an increase in the convected flux of angular momentum. (author)
Axisymmetric plasma equilibria in a Kerr metric
Elsässer, Klaus
2001-10-01
Plasma equilibria near a rotating black hole are considered within the multifluid description. An isothermal two-component plasma with electrons and positrons or ions is determined by four structure functions and the boundary conditions. These structure functions are the Bernoulli function and the toroidal canonical momentum per mass for each species. The quasi-neutrality assumption (no charge density, no toroidal current) allows to solve Maxwell's equations analytically for any axisymmetric stationary metric, and to reduce the fluid equations to one single scalar equation for the stream function \\chi of the positrons or ions, respectively. The basic smallness parameter is the ratio of the skin depth of electrons to the scale length of the metric and fluid quantities, and, in the case of an electron-ion plasma, the mass ratio m_e/m_i. The \\chi-equation can be solved by standard methods, and simple solutions for a Kerr geometry are available; they show characteristic flow patterns, depending on the structure functions and the boundary conditions.
[The birth of acknowledgement: Michel Foucault and Werner Leibbrand].
Mildenberger, Florian
2006-01-01
In 1964, Werner Leibbrand (1896-1974) was the first German medical historian to present, in Sudhoffs Archiv, a review of the work of Michel Foucault (1926-1984). This paper examines some of the reasons leading to the fact that Leibbrand's own generation refused to acknowledge the importance of Foucault's ideas, while, later on, younger German medical historians, although impressed with Foucault's writings, failed to acknowledge, first, the close relationship between Leibbrand's and Foucault's world views, and, second, Leibbrand's attempts at introducing Foucault to German medical historians. Leibbrand with his Jewish wife had survived the Nazi period partly in hiding. His attempts at clearing post-war German psychiatry and medical historiography of NS-sympathizers isolated him among his colleagues, many of whom had begun their career during the Third Reich. Leibbrand enjoyed the support by the Swiss medical historian and avowed Communist Erwin Ackerknecht (1906-1988), but later turned against him, possibly because Acknerknecht had called Leibbrand's writings "unscientific". Leibbrand was unable to overcome his antagonisms with his contemporaries. At the same time, opposition to Ackerknecht made him appear a respresentative of the past in the eyes of the younger generation. Thus, when Foucault was accepted by the latter, they were not prepared to examine the work of Leibbrand and realize how close some of the ideas developed by Leibbrand and Foucault had been.
A measurement of the tau Michel parameters at SLD
International Nuclear Information System (INIS)
Quigley, J.
1997-05-01
This thesis presents a measurement of the tau Michel parameters. This measurement utilizes the highly polarized SLC electron beam to extract these quantities directly from the measured tau decay spectra using the 1993--95 SLD sample of 4,528 tau pair events. The results are ρ e = 0.71 ± 0.14 ± 0.05, ξ e = 1.16 ± 0.52 ± 0.06, and (ξδ) e = 0.85 ± 0.43 ± 0.08 for tau decays to electrons and ρ μ = 0.54 ± 0.28 - 0.14, η μ = -0.59 ± 0.82 ± 0.45, ξ μ = 0.75 ± 0.50 ± 0.14, and (ξδ) μ = 0.82 ± 0.32 ± 0.07 for tau decays to muons. Combining all leptonic tau decays gives ρ = 0.72 ± 0.09 ± 0.03, ξ = 1.05 ± 0.35 ± 0.04, and Ξδ = 0.88 ± 0.27 ± 0.04. These results agree well with the current world average and the Standard Model
Optical activity via Kerr nonlinearity in a spinning chiral medium
Energy Technology Data Exchange (ETDEWEB)
Khan, Anwar Ali, E-mail: anwarali@uom.edu.pk [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Bacha, Bakht Amin, E-mail: aminoptics@gmail.com [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Khan, Rahmat Ali, E-mail: rahmat_alipk@yahoo.com [Department of Mathematics, University of Malakand (Pakistan)
2016-11-11
Optical activity is investigated in a chiral medium by employing the four level cascade atomic model, in which the optical responses of the atomic medium are studied with Kerr nonlinearity. Light entering into a chiral medium splits into circular birefringent beams. The angle of divergence between the circular birefringent beams and the polarization states of the two light beams is manipulated with Kerr nonlinearity. In the stationary chiral medium the angle of divergence between the circular birefringent beams is calculated to be 1.3 radian. Furthermore, circular birefringence is optically controlled in a spinning chiral medium, where the maximum rotary photon drag angle for left (right) circularly polarized beam is ±1.1 (±1.5) microradian. The change in the angle of divergence between circular birefringent beams by rotary photon drag is calculated to be 0.4 microradian. The numerical results may help to understand image designing, image coding, discovery of photonic crystals and optical sensing technology. - Highlights: • Coherent control of a circular birefringence in a chiral medium is studied. • Angle of divergence between birefringent beams is modified with Kerr nonlinearity. • Rotary photon drag is controlled for birefringent beams and enhanced with Kerr nonlinearity in a spinning medium. • Rotation of the angle of divergence is observed with mechanical rotation of the medium about an axis and modified with Kerr effect. • A change in the angle of divergence is calculated by about a microradian with rotary photon drag.
Revisiting scalar geodesic synchrotron radiation in Kerr spacetime
International Nuclear Information System (INIS)
Macedo, Caio F.B.; Crispino, Luis C.B.
2011-01-01
Full text: The Kerr solution [R. P. Kerr, Phys. Rev. D 11, 5 (1963)] is one of the most important black hole solutions of Einstein equations. It describes a chargeless rotating black hole, with Schwarzschild black hole as a particular case. It is estimated, inferred using distinct methods, that most black hole candidates have a considerable value of the rotation parameter [E. Berti, V. Cardoso, and A. Starinets, Classical Quantum Gravity 26, 163001 (2009)]. Although the Schwarzschild solution is suitable for a great variety of phenomena in star and black hole physics, the Kerr solution becomes very important in the explanation of the electrodynamical aspects of accretion disks for binary X-ray sources [The Kerr Spacetime: Rotating Black Holes in General Relativity, edited by D. L. Wiltshire, M. Visser, and S. M. Scott (Cambridge University Press, Cambridge, 2009)]. Thus, the investigation of how radiation emission processes are modified by the nontrivial curvature of rotating black holes is particularly important. As a first approximation to the problem, one can consider a moving particle, minimally coupled to the massless scalar field, in circular geodesic motion. The radiation emitted in this configuration is called scalar geodesic synchrotron radiation. In this work, we revisit the main aspects of scalar geodesic synchrotron radiation in Kerr spacetime, including some effects occurring in the high-frequency approximation. Our results can be readily compared with the results of the equivalent phenomena in Schwarzschild spacetime. (author)
Equatorial circular orbits in the Kerr-de Sitter spacetimes
International Nuclear Information System (INIS)
Stuchlik, Zdenek; Slany, Petr
2004-01-01
Equatorial motion of test particles in Kerr-de Sitter spacetimes is considered. Circular orbits are determined, their properties are discussed for both black-hole and naked-singularity spacetimes, and their relevance for thin accretion disks is established. The circular orbits constitute two families that coalesce at the so-called static radius. The orientation of the motion along the circular orbits is, in accordance with case of asymptotically flat Kerr spacetimes, defined by relating the motion to the locally nonrotating frames. The minus-family orbits are all counterrotating, while the plus-family orbits are usually corotating relative to these frames. However, the plus-family orbits become counterrotating in the vicinity of the static radius in all Kerr-de Sitter spacetimes, and they become counterrotating in the vicinity of the ring singularity in Kerr-de Sitter naked-singularity spacetimes with a low enough rotational parameter. In such spacetimes, the efficiency of the conversion of the rest energy into heat energy in the geometrically thin plus-family accretion disks can reach extremely high values exceeding the efficiency of the annihilation process. The transformation of a Kerr-de Sitter naked singularity into an extreme black hole due to accretion in the thin disks is briefly discussed for both the plus-family and minus-family disks. It is shown that such a conversion leads to an abrupt instability of the innermost parts of the plus-family accretion disks that can have strong observational consequences
The Kerr-Tomimatsu-Sato family of spinning mass solutions
International Nuclear Information System (INIS)
Yamazaki, M.
1982-01-01
The closed form with an arbitrary positive integer distortion parameter delta of the Kerr-Tomimatsu-Sato family of spinning mass solutions, i.e., stationary axisymmetric, asymptotically flat exact solutions of Einstein's vacuum field equations Rsub(μγ) = 0 is presented. The generalization of the Kerr-Tomimatsu-Sato family of solutions to the case of the arbitrary positive non-integral distortion parameter delta is conjectured. Some analytic properties of the family of solutions are studied. It is shown that all ring singularities are of first order and all ergosurfaces are simple zeros of metric functions f. The charged Kerr-Tomimatsu-Sato family of solutions is also given in the closed form with an arbitrary positive integer distortion parameter delta. It is shown that the Christodoulou-Ruffini mass formula of the Kerr-Newman field or the delta = 1 member of the present family of solutions also holds true in the case of the charged Kerr-Tomimatsu-Sato family of solutions with an arbitary odd integer delta. (Auth.)
Shadows of Kerr Black Holes with Scalar Hair.
Cunha, Pedro V P; Herdeiro, Carlos A R; Radu, Eugen; Rúnarsson, Helgi F
2015-11-20
Using backwards ray tracing, we study the shadows of Kerr black holes with scalar hair (KBHSH). KBHSH interpolate continuously between Kerr BHs and boson stars (BSs), so we start by investigating the lensing of light due to BSs. Moving from the weak to the strong gravity region, BSs-which by themselves have no shadows-are classified, according to the lensing produced, as (i) noncompact, which yield not multiple images, (ii) compact, which produce an increasing number of Einstein rings and multiple images of the whole celestial sphere, and (iii) ultracompact, which possess light rings, yielding an infinite number of images with (we conjecture) a self-similar structure. The shadows of KBHSH, for Kerr-like horizons and noncompact BS-like hair, are analogous to, but distinguishable from, those of comparable Kerr BHs. But for non-Kerr-like horizons and ultracompact BS-like hair, the shadows of KBHSH are drastically different: novel shapes arise, sizes are considerably smaller, and multiple shadows of a single BH become possible. Thus, KBHSH provide quantitatively and qualitatively new templates for ongoing (and future) very large baseline interferometry observations of BH shadows, such as those of the Event Horizon Telescope.
Ivask, Ivar, 1927-1992
2010-01-01
Michel Butor külastas 1971-1981 Oklahoma Ülikooli kolmel korral: 1971 esines loengutega, 1974 kuulus Neustadti kirjandusauhinna žüriisse ning 1981 toimus ülikoolis tema loomingule pühendatud Puterbaugh' konverents
Advanced MOKE magnetometry in wide-field Kerr-microscopy
Soldatov, I. V.; Schäfer, R.
2017-10-01
The measurement of MOKE (Magneto-Optical Kerr Effect) magnetization loops in a wide-field Kerr microscope offers the advantage that the relevant domain images along the loop can be readily recorded. As the microscope's objective lens is exposed to the magnetic field, the loops are usually strongly distorted by non-linear Faraday rotations of the polarized light that occur in the objective lens and that are superimposed to the MOKE signal. In this paper, an experimental method, based on a motorized analyzer, is introduced which allows to compensate the Faraday contributions, thus leading to pure MOKE loops. A wide field Kerr microscope, equipped with this technology, works well as a laser-based MOKE magnetometer, additionally offering domain images and thus providing the basis for loop interpretation.
Complex structure of Kerr geometry and rotating 'photon rocket' solutions
International Nuclear Information System (INIS)
Burinskii, Alexander
2003-01-01
In the frame of the Kerr-Schild approach, we obtain a generalization of the Kerr solution to a nonstationary case corresponding to a rotating source moving with arbitrary acceleration. Similar to the Kerr solution, the solutions obtained have geodesic and shearfree principal null congruence. The current parameters of the solutions are determined by a complex retarded-time construction via a given complex worldline of source. The real part of the complex worldline defines the values of the boost and acceleration while the imaginary part controls the rotation. The acceleration of the source is accompanied by lightlike radiation along the principal null congruence. The solutions obtained generalize to the rotating case the known Kinnersley class of the 'photon rocket' solutions
Joule-Thomson expansion of Kerr-AdS black holes
Energy Technology Data Exchange (ETDEWEB)
Oekcue, Oezguer; Aydiner, Ekrem [Istanbul University, Department of Physics, Faculty of Science, Istanbul (Turkey)
2018-02-15
In this paper, we study Joule-Thomson expansion for Kerr-AdS black holes in the extended phase space. A Joule-Thomson expansion formula of Kerr-AdS black holes is derived. We investigate both isenthalpic and numerical inversion curves in the T-P plane and demonstrate the cooling-heating regions for Kerr-AdS black holes. We also calculate the ratio between minimum inversion and critical temperatures for Kerr-AdS black holes. (orig.)
Effects of resonator input power on Kerr lens mode-locked lasers
Indian Academy of Sciences (India)
lasers. S KAZEMPOUR, A KESHAVARZ∗ and G HONARASA. Department of Physics, Faculty of Sciences, Shiraz University of Technology, Shiraz, Iran ... Keywords. Femtosecond pulses; Kerr lens sensitivity; Kerr lens mode-locked laser. ... The optical lengths of Kerr medium with thickness d and refractive index n under.
2010-04-16
... Drought Management Planning at the Kerr Hydroelectric Project, Flathead Lake, MT AGENCY: Bureau of Indian... Impact Statement (FEIS) for Drought Management Planning at the Kerr Hydroelectric Project, Flathead Lake... drought management planning at the Kerr Hydroelectric Project no sooner than 30 days following the...
Charged boson bound states in the kerr-newman metric
International Nuclear Information System (INIS)
Li Yuanjie; Zhang Duanming
1986-01-01
Charged boson bound states in Kerr-Newman metric are discussed. It is found that massless boson cannot be attracted by Kerr-Newman black hole to form bound states. For the massive boson, the condition of the nonbound states when 0 2 - Q 2 and both the condition and wave functions of the bound states when a = √M 2 - Q 2 are obtained. The energy mode of the bound states is single, E = (m√M 2 - Q 2 + eQM)/(2M 2 - Q 2 ). When Q = 0 or e = 0, the conclusion is in agreement with that of Zhang Shiwei and Su Rukeng
Polarizability of Fluid Droplets and the Kerr Effect on Microemulsions
Lisy, V
2001-01-01
Spheroidal fluid droplets immersed in another fluid and thermally fluctuating in the shape are considered. The polarizability of the droplet is evaluated up to the second order in the fluctuation amplitudes. The correlation functions of the polarizability tensor components are found and used to describe the polarized and depolarized scattering of light, and the Kerr effect on microemulsions. By comparison of the theoretical results with the Kerr constant measurements from the literature, we estimate the bending rigidity of the surfactant monolayer that separates the oil and water phases in droplet microemulsions.
Logarithmic corrections to black hole entropy from Kerr/CFT
International Nuclear Information System (INIS)
Pathak, Abhishek; Porfyriadis, Achilleas P.; Strominger, Andrew; Varela, Oscar
2017-01-01
It has been shown by A. Sen that logarithmic corrections to the black hole area-entropy law are entirely determined macroscopically from the massless particle spectrum. They therefore serve as powerful consistency checks on any proposed enumeration of quantum black hole microstates. Sen’s results include a macroscopic computation of the logarithmic corrections for a five-dimensional near extremal Kerr-Newman black hole. Here we compute these corrections microscopically using a stringy embedding of the Kerr/CFT correspondence and find perfect agreement.
Collapse of Incoherent Light Beams in Inertial Bulk Kerr Media
DEFF Research Database (Denmark)
Bang, Ole; Edmundson, Darran; Królikowski, Wieslaw
1999-01-01
We use the coherent density function theory to show that partially coherent beams are unstable and may collapse in inertial bulk Kerr media. The threshold power for collapse, and its dependence on the degree of coherence, is found analytically and checked-numerically. The internal dynamics of the...... of the walk-off modes is illustrated for collapsing and diffracting partially coherent beams.......We use the coherent density function theory to show that partially coherent beams are unstable and may collapse in inertial bulk Kerr media. The threshold power for collapse, and its dependence on the degree of coherence, is found analytically and checked-numerically. The internal dynamics...
Cross-Kerr nonlinearities in an optically dressed periodic medium
Energy Technology Data Exchange (ETDEWEB)
Slowik, K; Raczynski, A; Zaremba, J [Instytut Fizyki, Uniwersytet Mikolaja Kopernika, ulica Grudziadzka 5, 87-100 Torun (Poland); Zielinska-Kaniasty, S [Instytut Matematyki i Fizyki, Uniwersytet Technologiczno-Przyrodniczy, Aleja Prof. S Kaliskiego 7, 85-789 Bydgoszcz (Poland); Artoni, M [Department of Physics and Chemistry of Materials, CNR-INFM Sensor Lab, Brescia University and European Laboratory for Nonlinear Spectroscopy, Firenze (Italy); La Rocca, G C, E-mail: karolina@fizyka.umk.pl [Scuola Normale Superiore and CNISM, Pisa (Italy)
2011-02-15
Cross-Kerr nonlinearities are analyzed for two light beams propagating in an atomic medium in the tripod configuration, dressed by a strong standing-wave laser field that induces periodic optical properties. The reflection and transmission spectra as well as the phases of both the reflected and transmitted components of the two beams are analyzed theoretically with nonlinearities up to third order being taken into account. Ranges of parameters are sought in which the cross-Kerr effect can be used as the basis of the phase gate.
Logarithmic corrections to black hole entropy from Kerr/CFT
Energy Technology Data Exchange (ETDEWEB)
Pathak, Abhishek [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Porfyriadis, Achilleas P. [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Department of Physics, UCSB,Santa Barbara, CA 93106 (United States); Strominger, Andrew [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Varela, Oscar [Center for the Fundamental Laws of Nature, Harvard University,Cambridge, MA 02138 (United States); Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut),Am Mühlenberg 1, D-14476 Potsdam (Germany); Department of Physics, Utah State University,Logan, UT 84322 (United States)
2017-04-14
It has been shown by A. Sen that logarithmic corrections to the black hole area-entropy law are entirely determined macroscopically from the massless particle spectrum. They therefore serve as powerful consistency checks on any proposed enumeration of quantum black hole microstates. Sen’s results include a macroscopic computation of the logarithmic corrections for a five-dimensional near extremal Kerr-Newman black hole. Here we compute these corrections microscopically using a stringy embedding of the Kerr/CFT correspondence and find perfect agreement.
Black and gray Helmholtz-Kerr soliton refraction
International Nuclear Information System (INIS)
Sanchez-Curto, Julio; Chamorro-Posada, Pedro; McDonald, Graham S.
2011-01-01
Refraction of black and gray solitons at boundaries separating different defocusing Kerr media is analyzed within a Helmholtz framework. A universal nonlinear Snell's law is derived that describes gray soliton refraction, in addition to capturing the behavior of bright and black Kerr solitons at interfaces. Key regimes, defined by beam and interface characteristics, are identified, and predictions are verified by full numerical simulations. The existence of a unique total nonrefraction angle for gray solitons is reported; both internal and external refraction at a single interface is shown possible (dependent only on incidence angle). This, in turn, leads to the proposal of positive or negative lensing operations on soliton arrays at planar boundaries.
Entropy of Kerr-de Sitter black hole
Li, Huai-Fan; Ma, Meng-Sen; Zhang, Li-Chun; Zhao, Ren
2017-07-01
Based on the consideration that the black hole horizon and the cosmological horizon of Kerr-de Sitter black hole are not independent of each other, we conjecture the total entropy of the system should have an extra term contributed from the correlations between the two horizons, except for the sum of the two horizon entropies. By employing globally effective first law and effective thermodynamic quantities, we obtain the corrected total entropy and find that the region of stable state for Kerr-de Sitter is related to the angular velocity parameter a, i.e., the region of stable state becomes bigger as the rotating parameters a is increases.
Routes to spatiotemporal chaos in Kerr optical frequency combs.
Coillet, Aurélien; Chembo, Yanne K
2014-03-01
We investigate the various routes to spatiotemporal chaos in Kerr optical frequency combs, obtained through pumping an ultra-high Q-factor whispering-gallery mode resonator with a continuous-wave laser. The Lugiato-Lefever model is used to build bifurcation diagrams with regards to the parameters that are externally controllable, namely, the frequency and the power of the pumping laser. We show that the spatiotemporal chaos emerging from Turing patterns and solitons display distinctive dynamical features. Experimental spectra of chaotic Kerr combs are also presented for both cases, in excellent agreement with theoretical spectra.
Kerr-Newman metric in deSitter background
International Nuclear Information System (INIS)
Patel, L.K.; Koppar, S.S.; Bhatt, P.V.
1987-01-01
In addition to the Kerr-Newman metric with cosmological constant several other metrics are presented giving Kerr-Newman type solutions of Einstein-Maxwell field equations in the background of deSitter universe. The electromagnetic field in all the solutions is assumed to be source-free. A new metric of what may be termed as an electrovac rotating deSitter space-time- a space-time devoid of matter but containing source-free electromagnetic field and a null fluid with twisting rays-has been presented. In the absence of the electromagnetic field, these solutions reduce to those discussed by Vaidya (1984). 8 refs. (author)
Using iron line reverberation and spectroscopy to distinguish Kerr and non-Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Jiang, Jiachen; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 220 Handan Road, 200433 Shanghai (China); Steiner, James F., E-mail: jcjiang12@fudan.edu.cn, E-mail: bambi@fudan.edu.cn, E-mail: jsteiner@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2015-05-01
The iron Kα line commonly observed in the X-ray spectrum of both stellar-mass and supermassive black hole candidates is produced by the illumination of a cold accretion disk by a hot corona. In this framework, the activation of a new flaring region in the hot corona imprints a time variation on the iron line spectrum. Future X-ray facilities with high time resolution and large effective areas may be able to measure the so-called 2-dimensional transfer function; that is, the iron line profile detected by a distant observer as a function of time in response to an instantaneous flare from the X-ray primary source. This work is a preliminary study to determine if and how such a technique can provide more information about the spacetime geometry around the compact object than the already possible measurements of the time-integrated iron line profile. Within our simplified model, we find that a measurement of iron line reverberation can improve constraints appreciably given a sufficiently strong signal, though that most of the information is present in the time-integrated spectrum. Our aim is to test the Kerr metric. We find that current X-ray facilities and data are unable to provide strong tests of the Kerr nature of supermassive black hole candidates. We consider an optimistic case of 10{sup 5} iron line photons from a next-generation data set. With such data, the reverberation model improves upon the spectral constraint by an order of magnitude.
Domain structure in soft ferrites by the longitudinal Kerr effect
International Nuclear Information System (INIS)
Kaczmarek, R.; Dautain, M.; Barradi-Ismail, T.
1992-01-01
For the first time, the longitudinal Kerr effect has been used in order to observe magnetic domains and their development in power ferrites. Image subtraction and processing leads to a magnetic contrast being a quasi derivative of the domains. A kind of integration procedure applied to them permits a reconstruction of a local hysteresis which parameters closely approach the global hysteresis data. (orig.)
Cosmic censorship in a Kerr-like collapse scenario
Energy Technology Data Exchange (ETDEWEB)
Rudnicki, W. [Institute of Physics, Pedagogical University, Rzeszow (Poland)
1998-04-01
In this contribution we discuss a recent result which shows that a gravitational collapse cannot in generic situations lead to the formation of a final state resembling the Kerr solution with a naked singularity. This result supports the validity of the cosmic censorship hypothesis. (author)
Cosmic censorship in a Kerr-like collapse scenario
International Nuclear Information System (INIS)
Rudnicki, W.
1998-01-01
In this contribution we discuss a recent result which shows that a gravitational collapse cannot in generic situations lead to the formation of a final state resembling the Kerr solution with a naked singularity. This result supports the validity of the cosmic censorship hypothesis. (author)
Horizon geometry for Kerr black holes with synchronized hair
Delgado, Jorge F. M.; Herdeiro, Carlos A. R.; Radu, Eugen
2018-06-01
We study the horizon geometry of Kerr black holes (BHs) with scalar synchronized hair [1], a family of solutions of the Einstein-Klein-Gordon system that continuously connects to vacuum Kerr BHs. We identify the region in parameter space wherein a global isometric embedding in Euclidean 3-space, E3, is possible for the horizon geometry of the hairy BHs. For the Kerr case, such embedding is possible iff the horizon dimensionless spin jH (which equals the total dimensionless spin, j ), the sphericity s and the horizon linear velocity vH are smaller than critical values, j(S ),s(S ),vH(S ), respectively. For the hairy BHs, we find that jH
Giant Kerr nonlinearities using refractive-index enhancement
International Nuclear Information System (INIS)
Yavuz, D. D.; Sikes, D. E.
2010-01-01
By utilizing refractive-index enhancement with vanishing absorption, a scheme is suggested that achieves giant Kerr nonlinearities between two weak laser beams. One application of this scheme is discussed and an all-optical distributed Bragg reflector is proposed that works at very low light levels.
Non-linear Q-clouds around Kerr black holes
International Nuclear Information System (INIS)
Herdeiro, Carlos; Radu, Eugen; Rúnarsson, Helgi
2014-01-01
Q-balls are regular extended ‘objects’ that exist for some non-gravitating, self-interacting, scalar field theories with a global, continuous, internal symmetry, on Minkowski spacetime. Here, analogous objects are also shown to exist around rotating (Kerr) black holes, as non-linear bound states of a test scalar field. We dub such configurations Q-clouds. We focus on a complex massive scalar field with quartic plus hexic self-interactions. Without the self-interactions, linear clouds have been shown to exist, in synchronous rotation with the black hole horizon, along 1-dimensional subspaces – existence lines – of the Kerr 2-dimensional parameter space. They are zero modes of the superradiant instability. Non-linear Q-clouds, on the other hand, are also in synchronous rotation with the black hole horizon; but they exist on a 2-dimensional subspace, delimited by a minimal horizon angular velocity and by an appropriate existence line, wherein the non-linear terms become irrelevant and the Q-cloud reduces to a linear cloud. Thus, Q-clouds provide an example of scalar bound states around Kerr black holes which, generically, are not zero modes of the superradiant instability. We describe some physical properties of Q-clouds, whose backreaction leads to a new family of hairy black holes, continuously connected to the Kerr family
Carmona-Fonseca, Jaime
2006-12-01
Several techniques are available to measure red cell cholinesterase; therefore, evaluations with several methods provide a measure of concordance. An equation was formulated to transform native data of reference values to reference units of cholinesterase activity as measured by Michel and EQM tests. The experimental design was descriptive, transversal and prospective. The group sampled was a representative adult working population, aged 18-75, without previous exposure to cholinesterase inhibitors pesticides. The individuals were affiliated to the Social Security System and resided in Valle de Aburrá and Cercano Oriente Antioqueño (Antioquia Province, northwestern Colombia). Of 827 individuals, quantitative erythrocytes (Michel y EQM) tests exhibited "r" coefficients between 0.67 and R2 coefficient of 44%.,This indicated that one test explained the results in other test in 44% of the cases. The corelation was higher in Aburrá than in Oriente. The linear model for the 827 individuals was as follows: EQM U/g oxy-hemoglobin = 9.575 U/ g oxy-hemoglobin + 29.791 (Michel delta pH/hour). Michel delta pH/hr = 0.3312 delta pH/hour + 0.0149 (EQM U/g oxy-hemoglobin), where EQM was expressed in U/g oxy-hemoglobin and Michel pH change/hr. Inter-sections (coefficient a) and inclines (coefficient b) were significant in this model. In the adjusted equations, after exclusion of 12 extreme data (1.5% of 827), the r coefficient increased from 0.67 to 0.72 The adjusted equations were as follows: EQM U/g oxy-hemoglobin = 8.1884 U/g oxy-hemoglobin + 31.3920 (Michel delta pH/hour); Michel delta pH/hr = 0.2925 delta pH/hr + 0.0161 (EQM U/g oxy-hemoglobin). This system of linear equations permitted the transformation of Michel (delta PH/ hr) units to EQM (U/g oxy-hemoglobin) units and vice versa. This will facilitate data comparisons by clinicians and epidemiologists who are using these methods of cholinesterase measurement.
Simulacra, Symbolic Exchange and Technology in Michel Tournier's La Goutte d'Or
Directory of Open Access Journals (Sweden)
David W. Price
1993-06-01
Full Text Available In La Goutte d'Or , Michel Tournier offers a critique of Western culture by constructing a novel that reflects both Jean Baudrillard's theories of simulacra and the political economy of the sign and Martin Heidegger's meditations on technology. Tournier's novel explores the relationship between Heidegger's explanation of technology as an act of Enframing ( Ge-stell and Baudrillard's description of an economy based upon exchange-sign value. Thus, through La Goutte d 'Or , Michel Tournier depicts the violent confrontation between a symbolic exchange economy based on poietic acts and late capitalist economies of autonomized signs.
Observers in Kerr spacetimes. The ergoregion on the equatorial plane
Energy Technology Data Exchange (ETDEWEB)
Pugliese, D. [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics, Opava (Czech Republic); Quevedo, H. [Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico, DF (Mexico); Kazakh National University, Department of Theoretical and Nuclear Physics, Almaty (Kazakhstan)
2018-01-15
We perform a detailed analysis of the properties of stationary observers located on the equatorial plane of the ergosphere in a Kerr spacetime, including light-surfaces. This study highlights crucial differences between black hole and the super-spinner sources. In the case of Kerr naked singularities, the results allow us to distinguish between ''weak'' and ''strong'' singularities, corresponding to spin values close to or distant from the limiting case of extreme black holes, respectively. We derive important limiting angular frequencies for naked singularities. We especially study very weak singularities as resulting from the spin variation of black holes. We also explore the main properties of zero angular momentum observers for different classes of black hole and naked singularity spacetimes. (orig.)
Kerr Reservoir LANDSAT experiment analysis for March 1981
Lecroy, S. R. (Principal Investigator)
1982-01-01
LANDSAT radiance data were used in an experiment conducted on the waters of Kerr Reservoir to determine if reliable algorithms could be developed that relate water quality parameters to remotely sensed data. A mix of different types of algorithms using the LANDSAT bands was generated to provide a thorough understanding of the relationships among the data involved. Except for secchi depth, the study demonstrated that for the ranges measured, the algorithms that satisfactorily represented the data encompass a mix of linear and nonlinear forms using only one LANDSAT band. Ratioing techniques did not improve the results since the initial design of the experiment minimized the errors against which this procedure is effective. Good correlations were found for total suspended solids, iron, turbidity, and secchi depth. Marginal correlations were discovered for nitrate and tannin + lignin. Quantification maps of Kerr Reservoir are presented for many of the water quality parameters using the developed algorithms.
The Quantization of a Kerr-AdS Black Hole
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Claus Gerhardt
2018-01-01
Full Text Available We apply our model of quantum gravity to a Kerr-AdS space-time of dimension 2m+1, m≥2, where all rotational parameters are equal, resulting in a wave equation in a quantum space-time which has a sequence of solutions that can be expressed as a product of stationary and temporal eigenfunctions. The stationary eigenfunctions can be interpreted as radiation and the temporal ones as gravitational waves. The event horizon corresponds in the quantum model to a Cauchy hypersurface that can be crossed by causal curves in both directions such that the information paradox does not occur. We also prove that the Kerr-AdS space-time can be maximally extended by replacing in a generalized Boyer-Lindquist coordinate system the r variable by ρ=r2 such that the extended space-time has a timelike curvature singularity in ρ=-a2.
Linear Einstein equations and Kerr-Schild maps
International Nuclear Information System (INIS)
Gergely, Laszlo A
2002-01-01
We prove that given a solution of the Einstein equations g ab for the matter field T ab , an autoparallel null vector field l a and a solution (l a l c , T ac ) of the linearized Einstein equation on the given background, the Kerr-Schild metric g ac + λl a l c (λ arbitrary constant) is an exact solution of the Einstein equation for the energy-momentum tensor T ac + λT ac + λ 2 l (a T c)b l b . The mixed form of the Einstein equation for Kerr-Schild metrics with autoparallel null congruence is also linear. Some more technical conditions hold when the null congruence is not autoparallel. These results generalize previous theorems for vacuum due to Xanthopoulos and for flat seed spacetime due to Guerses and Guersey
Stationary spherical shells around Kerr-Newman naked singularities
International Nuclear Information System (INIS)
Zdenek Stuchlik; Stanislav Hledik
1998-01-01
It is shown that in the field of some Kerr-Newman naked singularities a stationary spherical shell of charged dust can exist, with the specific charge being the same for all particles of the dusty shell. Gravitational attractions acting on the particles are balanced by electromagnetic repulsion in such a way that the shell is stable against radial perturbations. Particles of the shell move along orbits with constant latitude and radius. Rotation of the shell is differential. The shell is corotating relative to static observers at infinity, but it is counter rotating relative to the family of locally non-rotating observers. No such a shell can exist in the field of Kerr-Newman black holes. (authors)
Photon emission of extremal Kerr-Newman black holes
Energy Technology Data Exchange (ETDEWEB)
Wei, Shao-Wen; Gu, Bao-Min; Wang, Yong-Qiang; Liu, Yu-Xiao [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China)
2017-02-15
In this paper, we deal with the null geodesics extending from the near-horizon region out to a distant observatory in an extremal Kerr-Newman black hole background. In particular, using the matched asymptotic expansion method, we analytically solve the null geodesics near the superradiant bound in the form of algebraic equations. For the case that the photon trajectories are limited in the equatorial plane, the shifts in the azimuthal angle and time are obtained. (orig.)
Vortical null orbits, repulsive barriers, energy confinement in Kerr metric
Energy Technology Data Exchange (ETDEWEB)
Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; De Felice, F
1978-10-01
The complete analytical description of the null trajectories in the field of a Kerr naked singularity is given. Two peculiar phenomena are described: the existence of repulsive barriers in the r < O world and the existence of null circular bound orbits which surround the singularity in 'shells'. They distribute around the surface at r = m, which is the position of the horizon in the extreme black-hole case; this suggests that a naked singularity 'remembers' the position of the last horizon.
Photon trajectories in the Kerr-Newman metric
Energy Technology Data Exchange (ETDEWEB)
Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; de Felice, F; Nobili, L [Palermo Univ. (Italy). Ist. di Fisica
1980-10-01
A more detailed description of the null trajectories in the Kerr-Newman metric is given. Interesting results which were not expected from what was known in the uncharged case are the considerable enhancement of the energy storage in a restricted region around the source in the use of a naked singularity case and the complete separation of the singularity from the asymptotic region in the sense that no photon can reach it even in the equatorial plane.
Quasinormal modes of Kerr-de Sitter black holes
International Nuclear Information System (INIS)
Yoshida, Shijun; Uchikata, Nami; Futamase, Toshifumi
2010-01-01
We calculate the fundamental quasinormal modes of the Kerr-de Sitter black hole for the first time. In order to calculate the quasinormal modes, we employ the master equations derived by Suzuki, Takasugi, and Umetsu, who transform the Teukolsky equations for the Kerr-de Sitter black hole into the standard form of the Heun's equation. The transformed functions are expanded around the outer horizon of the black hole or the symmetric axis in the Froebenius series whose coefficients satisfy a three-term recurrence relation. These three-term recurrence relations allow us to use Leaver's continued fraction method to calculate the angular separation constant and the quasinormal mode frequency. Any unstable fundamental quasinormal mode is not found in this paper. It is also observed that for some black holes characterized by a large mass parameter, some retrograde modes in the slow rotation limit become prograde as the black hole spin increases. This phenomenon does not occur for the fundamental modes of the Kerr black hole.
Quasilocal energy and surface geometry of Kerr spacetime
Yu, Chengjie; Liu, Jian-Liang
2017-04-01
We study the quasilocal energy (QLE) and the surface geometry for Kerr spacetime in the Boyer-Lindquist coordinates without taking the slow rotation approximation. We also consider in the region r ≤2 m , which is inside the ergosphere. For a certain region, r >rk(a ) , the Gaussian curvature of the surface with constant t , r is positive, and for r >√{3 }a the critical value of the QLE is positive. We found that the three curves: the outer horizon r =r+(a ), r =rk(a ) and r =√{3 }a intersect at the point a =√{3 }m /2 , which is the limit for the horizon to be isometrically embedded into R3. The numerical result indicates that the Kerr QLE is monotonically decreasing to the ADM m from the region inside the ergosphere to large r . Based on the second law of black hole dynamics, the QLE is increasing with respect to the irreducible mass Mir. From the results of Chen-Wang-Yau, we conclude that in a certain region, r >rh(a ), the critical value of the Kerr QLE is a global minimum.
Valley-selective optical Stark effect probed by Kerr rotation
LaMountain, Trevor; Bergeron, Hadallia; Balla, Itamar; Stanev, Teodor K.; Hersam, Mark C.; Stern, Nathaniel P.
2018-01-01
The ability to monitor and control distinct states is at the heart of emerging quantum technologies. The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for such control, with the optical Stark effect allowing for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-sensitive optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. More sensitive polarization-based spectroscopy is required to better probe ultrafast Stark shifts for all-optical manipulation of valley energy levels. Here, we show time-resolved Kerr rotation to be a more sensitive probe of the valley-selective optical Stark effect in monolayer TMDCs. Compared to the established time-resolved reflectance methods, Kerr rotation is less sensitive to background effects. Kerr rotation provides a fivefold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley and energy selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.
EIT enhanced self-Kerr nonlinearity in the three-level lambda system under Doppler broadening
International Nuclear Information System (INIS)
Doai, Le Van; Khoa, Dinh Xuan; Bang, Nguyen Huy
2015-01-01
Using density-matrix theory, an analytical expression of the self-Kerr nonlinear coefficient of a three-level lambda EIT medium for a weak probe light is derived. Influences of the coupling light and Doppler broadening on the self-Kerr coefficient are investigated and compared to experimental observation with a good agreement. The self-Kerr nonlinearity of the medium is modified and greatly enhanced in the spectral region of EIT window. Furthermore, sign, slope, and magnitude of the self-Kerr coefficient can be controlled with frequency and intensity of the coupling light and temperature of the medium. In particular, for a given set of fixed values of the parameter coupling and probe lights, it is possible to choose an optimized temperature with which to obtain the largest magnitude of the self-Kerr coefficient. Such a controllable Kerr nonlinearity can find interesting applications in optoelectronic devices working with low-light intensity at various temperature conditions. (paper)
EIT enhanced self-Kerr nonlinearity in the three-level lambda system under Doppler broadening
International Nuclear Information System (INIS)
Dinh Xuan Khoa; Le Van Doai; Pham Van Trong; Tran Manh Cuong; Vu Ngoc Sau; Nguyen Huy Bang; Le Nguyen Mai Anh
2014-01-01
Using density-matrix theory, an analytical expression of the self-Kerr nonlinear coefficient of a three-level lambda EIT medium for a weak probe light is derived. Influences of the coupling light and Doppler broadening on the self-Kerr coefficient are investigated and compared to experimental observation with a good agreement. The self-Kerr nonlinearity of the medium is modified and greatly enhanced in the spectral region of EIT window. Furthermore, sign, slope, and magnitude of the self-Kerr coefficient can be controlled with frequency and intensity of the coupling light and temperature of the medium. Specially, for a given set of fixed values of the parameters of coupling and probe lights, it could be able to choose an optimized temperature to have largest magnitude of the self-Kerr coefficient. Such controllable Kerr nonlinearity can find interesting applications in optoelectronic devices working with low-light intensity at various temperature conditions. (author)
Aspirational individuals in the work of Michel Houellebecq and James Buchanan
E. Dekker (Erwin)
2017-01-01
textabstractLoneliness and alienation are central themes in the work of French novelist Michel Houellebecq. His works Whatever (1998) and The Possibility of an Island (2004, hereafter TPI), which will be our central focus here, explore the extent to which man can be an island, or indeed is made into
Lire soumission entre Charlie hebdo et le Bataclan : L’islamisation selon Michel
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José Domingues de Almeida
2015-12-01
Full Text Available This paper aims to a critical reading of Michel Houellebecq’s novel Soumission (2015 just after Paris attacks, and intends to identify some features of continuity and rupture when compared with Houellebecq’s former novels’ narrative procedures and topics.
Lire soumission entre Charlie hebdo et le Bataclan : L’islamisation selon Michel
José Domingues de Almeida
2015-01-01
This paper aims to a critical reading of Michel Houellebecq’s novel Soumission (2015) just after Paris attacks, and intends to identify some features of continuity and rupture when compared with Houellebecq’s former novels’ narrative procedures and topics.
Lire soumission entre Charlie hebdo et le Bataclan : L’islamisation selon Michel
Directory of Open Access Journals (Sweden)
José Domingues de Almeida
2015-01-01
Full Text Available This paper aims to a critical reading of Michel Houellebecq’s novel Soumission (2015 just after Paris attacks, and intends to identify some features of continuity and rupture when compared with Houellebecq’s former novels’ narrative procedures and topics.
Prantsuse minister : Toidukontroll rangemaks! / Michel Barnier ; interv. Silja Lättemäe
Barnier, Michel, 1951-
2008-01-01
Ilmunud ka: Vesti Dnja 13. märts lk. 5. Oma intervjuus kinnitas Eestit väisanud Prantsuse põllumajandusminister Michel Barnier, et Prantsusmaa pooldab rangemat toiduohutuse kontrolli Euroopa Liidu välispiiril, samuti piimakvootide säilimist ja tootmise eelistamist maaelu arengule, Eestiga koostööd ollakse valmis tegema energeetikas
Justice vs. Power in reviewing by Noam Chomsky and Michel Foucault
Directory of Open Access Journals (Sweden)
Šuvaković Uroš V.
2012-01-01
Full Text Available This paper is a review of the debate led by Noam Chomsky and Michel Foucault in 1971. The debate was referred to both the principles of human knowledge and the need for political engagement of intellectuals led by the principle 'justice against the power', which is also the title of the transcript of this discussion published in Serbian in 2011. .
Qi, Jie
This paper explores how educators would raise different questions about educational issues by using Karl Marx's framework, Antonio Gramsci's conception, and Michel Foucault's notions, respectively. First, the paper compares the historical perspectives of Marx and Foucault. Marx concludes that history is a progressive linear production and that…
Abraham Pais Prize for History of Physics Talk: Henry Cavendish, John Michell, Weighing the Stars
McCormmach, Russell
2010-03-01
This talk is about an interaction between two 18th-century natural philosophers (physical scientists), Henry Cavendish and John Michell, and its most important outcome, the experiment of weighing the world (their name for it) using a torsion balance (our name for it). Michell was the most inventive of the 18th century English natural philosophers, and Cavendish was the first of his countrymen to possess abilities at all comparable with Newton's. By their interests and skills, they were drawn to one another. Both were universal natural philosophers, equally adept at building scientific instruments, performing experiments, constructing theory, and using mathematics; both had a penchant for exacting, quantitative work. Both also had fitful habits of publication, which did not begin to reveal the range of their work, to the mystification of later scientists and historians. Late in life, Cavendish and Michell turned their attention to the force that Newton had examined most completely, a singular triumph of his natural philosophy, the force of universal gravitation. Over the course of the 18th century, abundant evidence of attraction had been gathered from the motions of the earth, moon, planets, and comets, phenomena which span the intermediate range of masses, sizes, and distances. But in three domains of experience, involving the extreme upper and lower limits of masses and dimensions, the universality of gravitation remained an article of faith. These were the gravity of the ``fixed'' stars, the mutual attraction of terrestrial bodies, and the gravitation of light and other special substances. Michell took on himself the task of deducing observable consequences from each of these prospective instances of universal gravitation. Cavendish encouraged Michell, and he followed up the resulting observational and experimental questions. The experiment of weighing the world was the last experiment Mitchell planned and the last experiment Cavendish published. The capstone of
Mechanical Kerr nonlinearities due to bipolar optical forces between deformable silicon waveguides.
Ma, Jing; Povinelli, Michelle L
2011-05-23
We use an analytical method based on the perturbation of effective index at fixed frequency to calculate optical forces between silicon waveguides. We use the method to investigate the mechanical Kerr effect in a coupled-waveguide system with bipolar forces. We find that a positive mechanical Kerr coefficient results from either an attractive or repulsive force. An enhanced mechanical Kerr coefficient several orders of magnitude larger than the intrinsic Kerr coefficient is obtained in waveguides for which the optical mode approaches the air light line, given appropriate design of the waveguide dimensions.
Constraints on two accretion disks centered on the equatorial plane of a Kerr SMBH
Pugliese, Daniela; Stuchlík, Zdeněk
2017-12-01
The possibility that two toroidal accretion configurations may be orbiting around a super–massive Kerr black hole has been addressed. Such tori may be formed during different stages of the Kerr attractor accretion history. We consider the relative rotation of the tori and the corotation or counterrotation of a single torus with respect to the Kerr attractor. We give classification of the couples of accreting and non–accreting tori in dependence on the Kerr black hole dimensionless spin. We demonstrate that only in few cases a double accretion tori system may be formed under specific conditions.
Spherical null geodesics of rotating Kerr black holes
International Nuclear Information System (INIS)
Hod, Shahar
2013-01-01
The non-equatorial spherical null geodesics of rotating Kerr black holes are studied analytically. Unlike the extensively studied equatorial circular orbits whose radii are known analytically, no closed-form formula exists in the literature for the radii of generic (non-equatorial) spherical geodesics. We provide here an approximate formula for the radii r ph (a/M;cosi) of these spherical null geodesics, where a/M is the dimensionless angular momentum of the black hole and cos i is an effective inclination angle (with respect to the black-hole equatorial plane) of the orbit. It is well-known that the equatorial circular geodesics of the Kerr spacetime (the prograde and the retrograde orbits with cosi=±1) are characterized by a monotonic dependence of their radii r ph (a/M;cosi=±1) on the dimensionless spin-parameter a/M of the black hole. We use here our novel analytical formula to reveal that this well-known property of the equatorial circular geodesics is actually not a generic property of the Kerr spacetime. In particular, we find that counter-rotating spherical null orbits in the range (3√(3)−√(59))/4≲cosi ph (a/M;cosi=const) on the dimensionless rotation-parameter a/M of the black hole. Furthermore, it is shown that spherical photon orbits of rapidly-rotating black holes are characterized by a critical inclination angle, cosi=√(4/7), above which the coordinate radii of the orbits approach the black-hole radius in the extremal limit. We prove that this critical inclination angle signals a transition in the physical properties of the spherical null geodesics: in particular, it separates orbits which are characterized by finite proper distances to the black-hole horizon from orbits which are characterized by infinite proper distances to the horizon.
Quantization of a scalar field in the Kerr spacetime
International Nuclear Information System (INIS)
Ford, L.H.
1974-01-01
A discussion of field quantization in a curved background spacetime is presented, with emphasis on the quantization of a scalar field in the Kerr spacetime. The ambiguity in the choice of a Fock space is discussed. The example of quantized fields in a rotating frame of reference in Minkowski space is analyzed, and it is shown that there is a preferred choice of states which makes particle number an invariant under transformation to the rotating frame. This choice allows the existence of negative energy quanta of the field
Energy Technology Data Exchange (ETDEWEB)
Mello Junior, Antonio Goncalves de
2000-07-01
Several types of hydraulic turbines can be used in small hydroelectric power plant, as Pelton, Francis, Turgo, Kaplan, Propeller, Banki, etc. In Brazil the more used are Francis and Kaplan followed by Pelton. The usage of the other types is almost unknown, mainly the Turgo turbine. The cross flow turbine, also known by the names of Michell-Banki, Banki, and Michell-Ossberger is defined as an action turbine that can be applicable to falls from 1 to 200 m and flows from 0,025 to 13 m{sup 3}/s. With the technical evolution mainly in the last two decades by traditional firms like Ossberger Turbinenfabrik and new firms like CINK, that turbine can reach diameters of rotors of 1,0 m with width of 2,6 m and to develop capacity up to 2,000 k W, with efficiency near 90%. The main evolutions are concentrated in modifications presented in the injector of the turbine by several manufacturers, and the use of new materials in the blades of the runner, shafts, bearings and the use of the draft tube. Case study shows the technical and economical implications using a cross flow turbine in comparison to a Francis turbine and a Kaplan. The conclusions will be reported after technical and economical viability analysis among the three types of turbines. (author)
Managing the research university : Clark Kerr and the University of California
Soo, M; Carson, C
In the 1950s and 1960s, Clark Kerr led the University of California's Berkeley campus, and then the University of California as a whole. Throughout these years, he developed a system of managerial strategies. This paper shows how Kerr's administrative views drew upon his background in industrial
Massive-spin-1/2 wave around a Kerr-Newman black hole
International Nuclear Information System (INIS)
Lee, C.H.
1977-01-01
Using the separation of variables of the Dirac equations for the electron in the Kerr-Newman geometry, it is explicitly shown that the super-radiant scattering is not allowed for the electron wave on a Kerr-Newman black hole
Rizo, P. J.; Pugzlys, A.; Liu, J.; Reuter, D.; Wieck, A. D.; van der Wal, C. H.; van Loosdrecht, P. H. M.; Pugžlys, A.
2008-01-01
A compact cryogenic Kerr microscope for operation in the small volume of high-field magnets is described. It is suited for measurements both in Voigt and Faraday configurations. Coupled with a pulsed laser source, the microscope is used to measure the time-resolved Kerr rotation response of
Bartolomé de las Casas y Michel de Montaigne: Escritura y lectura del Nuevo Mundo
Directory of Open Access Journals (Sweden)
Juan Durán Luzio
2016-04-01
Full Text Available Se trata de mostrar cómo la obra de Bartolomé de Las Casas, Brevísima relación de la destrucción de las Indias, publicada en 1552 y traducida al francés en 1579,fue leída por Michel de Montaigne e incorporada en sus párrafos y doctrinas más relevantes en sus dos ensayos sobre el Nuevo Mundo: "Des Cannibales" (1580 y "Des Coches" (1588. The work of Bartolomé de Las Casas Brevísima relación de la destrucción de las Indias, published in 1552 and translated into French in 1579, is shown to have been read by Michel de Montaigne who included it in the most relevant paragraphs and doctrines in his two essays about the new world: "Des Cannibales" (1850 and "Des Coches" (1588.
Michel Borghini as a Mentor and Father of the Theory of Polarization in Polarized Targets
de Boer, Wim
2016-02-01
This paper is a contribution to the memorial session for Michel Borghini at the Spin 2014 conference in Bejing, honoring his pivotal role for the development of polarized targets in high energy physics. Borghini proposed for the first time the correct mechanism for dynamic polarization in polarized targets using organic materials doped with free radicals. In these amorphous materials the spin levels are broadened by spin-spin interactions and g-factor anisotropy, which allows a high dynamic polarization of nuclei by cooling of the spin-spin interaction reservoir. In this contribution I summarize the experimental evidence for this mechanism. These pertinent experiments were done at CERN in the years 1971 - 1974, when I was a graduate student under the guidance of Michel Borghini. I finish by shortly describing how Borghini’s spin temperature theory is now applied in cancer therapy.
Verdade e diferença no pensamento de Michel Foucault
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Cesar Candiotto
2007-01-01
Full Text Available O presente artigo versará sobre as articulações entre verdade e história no pensamento de Michel Foucault, e seu distanciamento da concepção originária e universalista de verdade. Acontecimento e diferença constituem conceitos decisivos para situar sua demarcação no domínio de estudo das ciências humanas, especialmente em seu primeiro grande livro, História da loucura na idade clássica.The paper deals with the articulation between truth and history in Michel Foucault's thought, and their separation from the originary and universal concept of truth. Event and difference constitute decisive concepts to situate his demarcation in the study domains of human sciences, especially in his first great book Madness and Civilization: A History of Insanity in the Age of Reason.
Topological Aspects of Entropy and Phase Transition of Kerr Black Holes
Institute of Scientific and Technical Information of China (English)
YANG Guo-Hong; YAN Ji-Jiang; TIAN Li-Jun; DUAN Yi-Shi
2005-01-01
In the light of topological current and the relationship between the entropy and the Euler characteristic, the topological aspects of entropy and phase transition of Kerr black holes are studied. From Gauss-Bonnet-Chern theorem,it is shown that the entropy of Kerr black holes is determined by the singularities of the Killing vector field of spacetime.By calculating the Hopf indices and Brouwer degrees of the Killing vector field at the singularities, the entropy S = A/4for nonextreme Kerr black holes and S = 0 for extreme ones are obtained, respectively. It is also discussed that, with the change of the ratio of mass to angular momentum for unit mass, the Euler characteristic and the entropy of Kerr black holes will change discontinuously when the singularities on Cauchy horizon merge with the singularities on event horizon, which will lead to the first-order phase transition of Kerr black holes.
Proposal for electro-optic multiplier based on dual transverse electro-optic Kerr effect.
Li, Changsheng
2008-10-20
A novel electro-optic multiplier is proposed, which can perform voltage multiplication operation by use of the Kerr medium exhibiting dual transverse electro-optic Kerr effect. In this kind of Kerr medium, electro-optic phase retardation is proportional to the square of its applied electric field, and orientations of the field-induced birefringent axes are only related to the direction of the field. Based on this effect, we can design an electro-optic multiplier by selecting the crystals of 6/mmm, 432, and m3m classes and isotropic Kerr media such as glass. Simple calculation demonstrates that a kind of glass-ceramic material with a large Kerr constant can be used for the design of the proposed electro-optic multiplier.
Almeida, José Domingues de
2015-01-01
Cet article vise une lecture critique du roman Soumission (2015) de Michel Houellebecq dans la foulée des attentats parisiens, en essayant de détecter les lignes de continuité et de rupture par rapport aux procédés narratifs employés et aux thématiques présentes dans les romans précédents.
War, Power and Liberalism: the Politicization in the Work of Michel Foucault
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Joaquín Fortanet
2009-04-01
Full Text Available This paper attempts to examine the analysis on liberalism that Michel Foucault developed during his last courses in the Collège de France. This analysis becomes a redefinition of the concept of power, understood as war, and a reflection on the concepts of security and population, by means of which the relation between war, power and liberalism offers a map of the present time, an age when the new rationalityof government can be defined as specifically liberal.
Robert Michels y las teorías elitista-competitivas de la democracia
Caparrós Valderrama, Rafael
2008-01-01
Robert Michel's main work is "Political parties. A Sociological Study on the Oligarchical Tendencies of Modern Democracy", issued in 1911, which is an analysis on the internal organization evolving dynamics of the German Social-Democrat Party (SDP), to which the author was intensely attached for several years. The aim of this essay is hte sociological study of the leadership emergence, power psicology and the organizational oligarchical tendencies. In it all argumentation can be found on the ...
L’église Saint-Michel de Lille : chronologie d’un chantier
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Catherine Guillot
2012-04-01
Full Text Available Après le démantèlement des fortifications de Lille en 1858, un nouveau quartier est aménagé au sud de la ville, dont un des équipements importants est l’église Saint-Michel, construite entre 1868 et 1874 par l’architecte Alfred Coisel. Très bien documenté, son chantier dévoile un mobilier et un décor exemplaire par son homogénéité et par la place accordée à la peinture murale. Cette étude met en évidence, outre le rôle du peintre Alphonse Colas, des artistes méconnus comme Albéric Duyver et Marie Carin. L’iconographie, qui révèle un des plus importants cycles consacrés à l’archange saint Michel, est également extrêmement caractéristique de son temps.After the demolition of the fortifications at Lille, in 1858, a new quarter developed to the south of the city. One of the important features of this new neighbourhood was the Saint-Michel church, built between 1868 and 1874 to the designs of the architect Alfred Coisel. The building of this church is exceptionally well documented and reveals church furnishings and decoration of an exemplary nature in terms of homogeneity and the special place given over to mural paintings. This study underlines the role of the painter Alphonse Colas, but also the contribution of other, less well known artists such as Albéric Duyver and Marie Carin. The iconographical theme is one of the most important cycles of its time devoted to the archangel Saint Michel, and is highly characteristic of the period.
[Maria Goeppert-Mayer Award to Taiwan-born and raised American physicist Michele Ma Chung-pei
2003-01-01
"The American Physical Society conferred the prestigious Maria Goeppert-Mayer Award to Taiwan-born and raised American physicist Michele Ma Chung-pei recently in recognition of her important contributions to theoretical astrophysics" (1 page).
Iron Kα line of Kerr black holes with scalar hair
Energy Technology Data Exchange (ETDEWEB)
Ni, Yueying; Zhou, Menglei; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 220 Handan Road, 200433 Shanghai (China); Cárdenas-Avendaño, Alejandro [Programa de Matemática, Fundación Universitaria Konrad Lorenz, Carrera 9 Bis No. 62-43, 110231 Bogotá (Colombia); Herdeiro, Carlos A R; Radu, Eugen, E-mail: yyni13@fudan.edu.cn, E-mail: mlzhou13@fudan.edu.cn, E-mail: alejandro.cardenasa@konradlorenz.edu.co, E-mail: bambi@fudan.edu.cn, E-mail: herdeiro@ua.pt, E-mail: eugen.radu@ua.pt [Departamento de Física da Universidade de Aveiro and Center for Research and Development in Mathematics and Applications (CIDMA), Campus de Santiago, 3810-183 Aveiro (Portugal)
2016-07-01
Recently, a family of hairy black holes in 4-dimensional Einstein gravity minimally coupled to a complex, massive scalar field was discovered [1]. Besides the mass M and spin angular momentum J , these objects are characterized by a Noether charge Q , measuring the amount of scalar hair, which is not associated to a Gauss law and cannot be measured at spatial infinity. Introducing a dimensionless scalar hair parameter q , ranging from 0 to 1, we recover (a subset of) Kerr black holes for q = 0 and a family of rotating boson stars for q = 1. In the present paper, we explore the possibility of measuring q for astrophysical black holes with current and future X-ray missions. We study the iron Kα line expected in the reflection spectrum of such hairy black holes and we simulate observations with Suzaku and eXTP. As a proof of concept, we point out, by analyzing a sample of hairy black holes, that current observations can already constrain the scalar hair parameter q , because black holes with q close to 1 would have iron lines definitively different from those we observe in the available data. We conclude that a detailed scanning of the full space of solutions, together with data from the future X-ray missions, like eXTP, will be able to put relevant constraints on the astrophysical realization of Kerr black holes with scalar hair.
The Kerr/CFT Correspondence and its Extensions
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Geoffrey Compère
2012-10-01
Full Text Available We present a first-principles derivation of the main results of the Kerr/CFT correspondence and its extensions using only tools from gravity and quantum field theory, filling a few gaps in the literature when necessary. Firstly, we review properties of extremal black holes that imply, according to semi-classical quantization rules, that their near-horizon quantum states form a centrally-extended representation of the one-dimensional conformal group. This motivates the conjecture that the extremal Kerr and Reissner–Nordström black holes are dual to the chiral limit of a two-dimensional CFT. We also motivate the existence of an SL (2,ℤ family of two-dimensional CFTs, which describe in their chiral limit the extremal Kerr–Newman black hole. We present generalizations in anti-de Sitter spacetime and discuss other matter-coupling and higher-derivative corrections. Secondly, we show how a near-chiral limit of these CFTs reproduces the dynamics of near-superradiant probes around near-extremal black holes in the semi-classical limit. Thirdly, we review how the hidden conformal symmetries of asymptotically-flat black holes away from extremality, combined with their properties at extremality, allow for a microscopic accounting of the entropy of non-extremal asymptotically-flat rotating or charged black holes. We conclude with a list of open problems.
A Zeroth Law Compatible Model to Kerr Black Hole Thermodynamics
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Viktor G. Czinner
2017-02-01
Full Text Available We consider the thermodynamic and stability problem of Kerr black holes arising from the nonextensive/nonadditive nature of the Bekenstein–Hawking entropy formula. Nonadditive thermodynamics is often criticized by asserting that the zeroth law cannot be compatible with nonadditive composition rules, so in this work we follow the so-called formal logarithm method to derive an additive entropy function for Kerr black holes also satisfying the zeroth law’s requirement. Starting from the most general, equilibrium compatible, nonadditive entropy composition rule of Abe, we consider the simplest non-parametric approach that is generated by the explicit nonadditive form of the Bekenstein–Hawking formula. This analysis extends our previous results on the Schwarzschild case, and shows that the zeroth law-compatible temperature function in the model is independent of the mass–energy parameter of the black hole. By applying the Poincaré turning point method, we also study the thermodynamic stability problem in the system.
Faraday and Kerr Effects Diagnostics for Underwater Exploding Wires
Sarkisov, G. S.; Fedotov-Gefen, A. V.; Krasik, Ya. E.
2012-10-01
Two-channel laser polarimeter was used to measure magnetic and electric fields in vicinity of underwater exploding wire. Nd:YAG Q-switch laser with 532nm wavelength, 100mJ energy and 5ns pulse width was used for probing. Single wire, parallel wires and X and V- shaped wires was used in experiments. Electric and magnetic field induced birefringes in the water results in changing of polarization stage of probing beam after propagation through this anisotropic medium. Magnetic field results in circular anisotropy of the water, while electric field creates linear anisotropy. Magnetic field results in rotation of polarization plan of linear-polarized probing beam. Electric field effect is more complicated- polarization plan of the laser beam subjected to pulsation and changing of ellipticity. Effect of electric field depends on initial probing geometry- angle between electrical field vector E and polarization plane of probing wave. In our exploding wire experiments we found influence of both Faraday and Kerr effects. It was demonstrated existence of Kerr effect inside bubbles at high voltage electrode. Effect of magnetic fields interaction for multi-wire loads was observed.
Magnification relations for Kerr lensing and testing cosmic censorship
International Nuclear Information System (INIS)
Werner, M. C.; Petters, A. O.
2007-01-01
A Kerr black hole with mass parameter m and angular momentum parameter a acting as a gravitational lens gives rise to two images in the weak field limit. We study the corresponding magnification relations, namely, the signed and absolute magnification sums and the centroid up to post-Newtonian order. We show that there are post-Newtonian corrections to the total absolute magnification and centroid proportional to a/m, which is in contrast to the spherically symmetric case where such corrections vanish. Hence we also propose a new set of lensing observables for the two images involving these corrections, which should allow measuring a/m with gravitational lensing. In fact, the resolution capabilities needed to observe this for the Galactic black hole should in principle be accessible to current and near-future instrumentation. Since a/m>1 indicates a naked singularity, a most interesting application would be a test of the cosmic censorship conjecture. The technique used to derive the image properties is based on the degeneracy of the Kerr lens and a suitably displaced Schwarzschild lens at post-Newtonian order. A simple physical explanation for this degeneracy is also given
Cosmic censorship conjecture in Kerr-Sen black hole
Gwak, Bogeun
2017-06-01
The validity of the cosmic censorship conjecture for the Kerr-Sen black hole, which is a solution to the low-energy effective field theory for four-dimensional heterotic string theory, is investigated using charged particle absorption. When the black hole absorbs the particle, the charge on it changes owing to the conserved quantities of the particle. Changes in the black hole are constrained to the equation for the motion of the particle and are consistent with the laws of thermodynamics. Particle absorption increases the mass of the Kerr-Sen black hole to more than that of the absorbed charges such as angular momentum and electric charge; hence, the black hole cannot be overcharged. In the near-extremal black hole, we observe a violation of the cosmic censorship conjecture for the angular momentum in the first order of expansion and the electric charge in the second order. However, considering an adiabatic process carrying the conserved quantities as those of the black hole, we prove the stability of the black hole horizon. Thus, we resolve the violation. This is consistent with the third law of thermodynamics.
Direct imaging rapidly-rotating non-Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Bambi, Cosimo, E-mail: Cosimo.Bambi@physik.uni-muenchen.de [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universitaet Muenchen, 80333 Munich (Germany); Caravelli, Francesco, E-mail: fcaravelli@perimeterinstitute.ca [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, 14476 Golm (Germany); Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Modesto, Leonardo, E-mail: lmodesto@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada)
2012-05-01
Recently, two of us have argued that non-Kerr black holes in gravity theories different from General Relativity may have a topologically non-trivial event horizon. More precisely, the spatial topology of the horizon of non-rotating and slow-rotating objects would be a 2-sphere, like in Kerr space-time, while it would change above a critical value of the spin parameter. When the topology of the horizon changes, the black hole central singularity shows up. The accretion process from a thin disk can potentially overspin these black holes and induce the topology transition, violating the Weak Cosmic Censorship Conjecture. If the astrophysical black hole candidates are not the black holes predicted by General Relativity, we might have the quite unique opportunity to see their central region, where classical physics breaks down and quantum gravity effects should appear. Even if the quantum gravity region turned out to be extremely small, at the level of the Planck scale, the size of its apparent image would be finite and potentially observable with future facilities.
Abdesselam, A.
2017-06-22
We present the first measurement of the Michel parameters $\\bar{\\eta}$ and $\\xi\\kappa$ in the radiative leptonic decay of the $\\tau$ lepton using 703 f$\\mathrm{b}^{-1}$ of data collected with the Belle detector at the KEKB $e^+e^-$ collider. The Michel parameters are measured by an unbinned maximum likelihood fit to the kinematic information of $e^+e^-\\rightarrow\\tau^+\\tau^-\\rightarrow (\\pi^+\\pi^0 \\bar{\
Entanglement dynamics of a double two-photon Jaynes–Cummings model with Kerr-like medium
International Nuclear Information System (INIS)
Xi-Cheng, Ouyang; Mao-Fa, Fang; Guo-Dong, Kang; Xiao-Juan, Deng; Li-Yuan, Huang
2010-01-01
In this paper, the entanglement dynamics of a double two-photon Jaynes–Cummings model with Kerr-like medium is investigated. It is shown that initial entanglement has an interesting subsequent time evolution, including the so-called entanglement sudden death effect. It is also shown analytically that the Kerr-like medium can repress entanglement sudden death and enhance the degree of atom-atom entanglement. A more interesting fact is that the Kerr effect is more obvious when each of the two cavities with have the Kerr-like medium than only one of them with the Kerr-like medium
Energy Technology Data Exchange (ETDEWEB)
Belhai, D.; Ouabadi, A.
2016-10-01
Michel Durand-Delga made a success of an outstanding career in geology. His route might be considered as one of a pioneer of a new kind. He set a meticulous rhythm in this discipline of the Earth sciences, particularly in Algeria, the country he loved for its geology, landscapes and population. The first of his fructuous works was published in 1948 on the geology of the Petite Kabylie and he continued, for most his life, to work very closely on this zone which he characterized, in a definitive way, as different from the African continent with at first structural then stratigraphical evidence. He highlighted the Kabylian thrust where the northern domain (internal, also called Kabyle) overlaps a southern domain (external or African). All the geological information that came later either produced by him or later by his students and opponents supported this great hypothesis which today has become a reliable paradigm. (Author)
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Petr Kyloušek
2015-12-01
Full Text Available In the frame of Quebec literature, Michel Tremblay’s poetics is an attempt to transfiguration of plebeian axiology in high literature, universal in scope. The slang of the Montreal periphery (so called joual and its speakers, which are mostly marginal characters, are highlighted by the application of the principles of religious drama, Greek tragedy and opera as the constituent parts of Tremblay’s theater and prose. To identify and illustrate these principles at different structural levels, the paper analyses the novels Le Premier Quartier de la lune (1989, Le cahier noir (2003, La Traversée de la ville (2008 and the drama Sainte Carmen de la Main (1976.
Magneto-optical Kerr spectroscopy of noble metals
Uba, L.; Uba, S.; Antonov, V. N.
2017-12-01
Magneto-optical (MO) response of the noble metals Cu, Ag, and Au in the joint experimental and ab initio theoretical study is reported. The magneto-optical polar Kerr effect (MOKE) spectra of the noble-metal films were measured with the high sensitivity in the applied magnetic field of 1.5 T over the photon energy range 0.74-5.8 eV. Complete set of the optical conductivity tensor elements was determined precisely from the MOKE and the optical spectra measured at the same energy points. The importance of the off-diagonal intraband Drude-type transitions is demonstrated explicitly for each noble metal and found to be a substantial contribution to the observed spectra. It is shown that the first-principles calculations using the spin-polarized fully relativistic Dirac linear-muffin-tin-orbital method with the inclusion of correlation effects by GGA+U approach reproduce well the experimental spectra and allow to explain the microscopic origin of the noble metals' magneto-optical response in terms of interband transitions. Although the energy band structures of Cu, Ag, and Au are very similar, there are some distinctive differences in bandwidths and the energy positions of the bands (especially in X and L symmetry points), mainly due to different spin-orbit splitting and differences in the spatial extent of 3 d , 4 d , and 5 d valence wave functions of noble metals. It was found that the small differences in the band positions lead to significant differences in the MO properties of three noble metals. Although the spin-orbit interaction in Au is about six times larger than in Cu, and approximately two times larger than in Ag, the absolute value of Kerr rotation in Au is of the same magnitude as in Cu and one order of magnitude smaller as compared to Ag. The sharp Kerr effect spectral peak in Ag is not due to the electronic interband transitions, but rather to the plasma-edge splitting. The band-by-band decomposition of the Cu, Ag, and Au MO spectra is presented and the
Spinning Kerr black holes with stationary massive scalar clouds: the large-coupling regime
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [Marine sciences, The Ruppin Academic Center,Ruppin, Emeq Hefer 40250 (Israel); Biotechnology, The Hadassah Academic College,37 Hanevi’im St., Jerusalem 9101001 (Israel)
2017-01-09
We study analytically the Klein-Gordon wave equation for stationary massive scalar fields linearly coupled to spinning Kerr black holes. In particular, using the WKB approximation, we derive a compact formula for the discrete spectrum of scalar field masses which characterize the stationary composed Kerr-black-hole-massive-scalar-field configurations in the large-coupling regime Mμ≫1 (here M and μ are respectively the mass of the central black hole and the proper mass of the scalar field). We confirm our analytically derived formula for the Kerr-scalar-field mass spectrum with numerical data that recently appeared in the literature.
Hawking radiation of Dirac particles in the hot NUT-Kerr-Newman spacetime
International Nuclear Information System (INIS)
Ahmed, M.
1991-01-01
The Hawking radiation of charged Dirac particles on the horizons of the hot NUT-Kerr-Newman spacetime is studied in this paper. To this end, we obtain the radial decoupled Dirac equation for the electron in the hot NUT-Kerr-Newman spacetime. Next we solve the Dirac equation near the horizons. Finally, by analytic continuation, the Hawking thermal spectrum formula of Dirac particles is obtained. The problem of the Hawking evaporation of Dirac particles in the hot NUT-Kerr-Newman background is thus solved. (orig.)
Fluctuating twistor-beam solutions and Pre-Quantum Kerr-Schild geometry
Energy Technology Data Exchange (ETDEWEB)
Burinskii, Alexander, E-mail: bur@ibrae.ac.r [Laboratory of Theoretical Physics, NSI Russian Academy of Sciences, B.Tulskaya 52, Moscow, 115191 (Russian Federation)
2010-04-01
Kerr-Schild (KS) geometry is based on a congruence of twistors which is determined by the Kerr theorem. We describe time-dependent KS solutions for electromagnetic excitations of black-holes taking into account the consistent back-reaction to metric. The exact solutions have the form of singular beam-like pulses supported on twistor null lines of the Kerr congruence. The twistor-beams have very strong back reaction to metric and BH horizon and produce a fluctuating KS geometry which takes an intermediate position between the Classical and Quantum gravity.
Fluctuating twistor-beam solutions and Pre-Quantum Kerr-Schild geometry
International Nuclear Information System (INIS)
Burinskii, Alexander
2010-01-01
Kerr-Schild (KS) geometry is based on a congruence of twistors which is determined by the Kerr theorem. We describe time-dependent KS solutions for electromagnetic excitations of black-holes taking into account the consistent back-reaction to metric. The exact solutions have the form of singular beam-like pulses supported on twistor null lines of the Kerr congruence. The twistor-beams have very strong back reaction to metric and BH horizon and produce a fluctuating KS geometry which takes an intermediate position between the Classical and Quantum gravity.
Transients of the electromagnetically-induced-transparency-enhanced refractive Kerr nonlinearity
International Nuclear Information System (INIS)
Pack, M. V.; Camacho, R. M.; Howell, J. C.
2007-01-01
We report observations of the dynamics of electromagnetically induced transparency (EIT) in a Λ system when the ground states are Stark shifted. Interactions of this type exhibit large optical nonlinearities called Kerr nonlinearities, and have numerous applications. The EIT Kerr nonlinearity is relatively slow, which is a limiting factor that may make many potential applications impossible. Using rubidium atoms, we observe the dynamics of the EIT Kerr nonlinearity using a Mach-Zehnder interferometer to measure phase modulation of the EIT fields resulting from a pulsed signal beam Stark shifting the ground state energy levels. The rise times and transients agree well with theory
DEFF Research Database (Denmark)
Plum, Maja
2012-01-01
Denne antologi introducerer til centrale politologiske, filosofiske, sociologiske, økonomiske og psykologiske tænkere og perspektiver, hvis teorier kan anvendes som analytiske redskaber og rammer inden for det sociale felt. Bogen giver læseren redskaber til at reflektere over og skabe kobling mel...
ISCO and Principal Null Congruences in Extremal Kerr Spacetime
International Nuclear Information System (INIS)
Pradhan, Parthapratim
2012-01-01
The effective potential in universal like coordinates(U, V, θ, φ), which are smooth across the event horizon is derived and investigated the ISCO(Innermost Stable Circular Orbits) explicitly in these coordinates for extremal Kerr spacetime. Extremization of the effective potential for timelike circular orbit shows that the existence of a stable circular geodesics in the extremal spacetime for direct orbit, precisely on the event horizon in terms of the radial coordinate which coincides with the principal null geodesic congruences of the event horizon. These null geodesic congruences mold themselves to the spacetime curvature in such a way that Weyl conformal tensor and its dual are vanished, that is why they are in-fact doubly degenerate principal null congruences.
Higher-order geodesic deviations applied to the Kerr metric
Colistete, R J; Kerner, R
2002-01-01
Starting with an exact and simple geodesic, we generate approximate geodesics by summing up higher-order geodesic deviations within a general relativistic setting, without using Newtonian and post-Newtonian approximations. We apply this method to the problem of closed orbital motion of test particles in the Kerr metric spacetime. With a simple circular orbit in the equatorial plane taken as the initial geodesic, we obtain finite eccentricity orbits in the form of Taylor series with the eccentricity playing the role of a small parameter. The explicit expressions of these higher-order geodesic deviations are derived using successive systems of linear equations with constant coefficients, whose solutions are of harmonic oscillator type. This scheme gives best results when applied to orbits with low eccentricities, but with arbitrary possible values of (GM/Rc sup 2).
Improved approximate inspirals of test bodies into Kerr black holes
International Nuclear Information System (INIS)
Gair, Jonathan R; Glampedakis, Kostas
2006-01-01
We present an improved version of the approximate scheme for generating inspirals of test bodies into a Kerr black hole recently developed by Glampedakis, Hughes and Kennefick. Their original 'hybrid' scheme was based on combining exact relativistic expressions for the evolution of the orbital elements (the semilatus rectum p and eccentricity e) with an approximate, weak-field, formula for the energy and angular momentum fluxes, amended by the assumption of constant inclination angle ι during the inspiral. Despite the fact that the resulting inspirals were overall well behaved, certain pathologies remained for orbits in the strong-field regime and for orbits which are nearly circular and/or nearly polar. In this paper we eliminate these problems by incorporating an array of improvements in the approximate fluxes. First, we add certain corrections which ensure the correct behavior of the fluxes in the limit of vanishing eccentricity and/or 90 deg. inclination. Second, we use higher order post-Newtonian formulas, adapted for generic orbits. Third, we drop the assumption of constant inclination. Instead, we first evolve the Carter constant by means of an approximate post-Newtonian expression and subsequently extract the evolution of ι. Finally, we improve the evolution of circular orbits by using fits to the angular momentum and inclination evolution determined by Teukolsky-based calculations. As an application of our improved scheme, we provide a sample of generic Kerr inspirals which we expect to be the most accurate to date, and for the specific case of nearly circular orbits we locate the critical radius where orbits begin to decircularize under radiation reaction. These easy-to-generate inspirals should become a useful tool for exploring LISA data analysis issues and may ultimately play a role in the detection of inspiral signals in the LISA data
‘Michel de Certeau. Le marcheur blessé’.
Directory of Open Access Journals (Sweden)
François Dosse
2002-09-01
Full Text Available Quatrième de couverture. Jésuite et historien spécialiste du 17 e siècle et de la mystique, sociologue de la culture du quotidien, anthropologue, sémiologue et cofondateur de l'école lacanienne, Michel de Certeau est une figure singulière de l'histoire intellectuelle du 20 e siècle. Célébré par le tout-Paris lors de sa disparition en janvier 1986, il fut toute sa vie un franc-tireur. Position qui n'a sans doute pas permis de mesurer son apport au renouvellement des ...
Literary Practice according to Michel Henry: A Philosophical Introduction to his Novels
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Jean-Baptiste Dussert
2012-12-01
Full Text Available Although the author of four novels, Michel Henry never produced an aesthetics of literature. The purpose of this article is, after a presentation of his philosophy of immanence and his concept of life, to locate where the literary practice takes place in his system. In this study, we are not interested in the poetic quality of his works, but in the possibility to base his singular creativity on his philosophical reflection. This leads us to insert literature in the vast phenomenon of culture and ethics, and to grasp the function of poetics in the struggle against barbarism.
Hilbers, Antonis
2001-01-01
Die vorliegende Dissertation schließt eine doppelte Forschungslücke: zum einen wird erstmals im Bereich der deutschsprachigen Romanistik dem Werk des 1933 in Madrid geborenen und seit 1957 im französischen Literaturbetrieb fortwährend präsenten Autors Michel del Castillo eine monographische Studie gewidmet. Zum anderen handelt es sich um die erste Arbeit überhaupt, die das Frühwerk (den Hypotext "Tanguy", 1957) mit dem Spätwerk del Castillos (den Hypertexten "Le crime des pères", 1993 und "Ru...
O deserto e o espelho. Refletindo sobre a heterotopia com Michel Foucault e Nadine Gordimer
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Anderson Bastos Martins
2009-06-01
Full Text Available Este ensaio representa uma tentativa de releitura do artigo “De outros espaços”, de Michel Foucault, seguindo uma análise da relaçáo estabelecida entre a protagonista do romance The pickup [O engate], de Nadine Gordimer, e o deserto, durante a viagem que ela faz à casa de campo de seu noivo. Apresentaremos um reenfoque do conceito foucaultiano de heterotopia através da elucidaçáo de sua noçáo de espelho e sua contribuiçáo potencial para refletir sobre a experiência espacial na contemporaneidade.
Marées et touristes au Mont-Saint-Michel
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Fernand Verger
2001-09-01
Full Text Available L’imaginaire collectif fait la plus grande place au phénomène des grandes marées dans la baie du Mont-Saint-Michel, mais la fréquentation touristique n’est que faiblement déterminée par l’occurrence des grandes marées, malgré l’existence d’un public spécifique, relativement peu nombreux, attiré par le spectacle du mascaret.
A Measurement of the Michel Parameters in Leptonic Decays of the Tau
Energy Technology Data Exchange (ETDEWEB)
Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Darling, C.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N. [University of Kansas, Lawrence, Kansas 66045 (United States); Anderson, S.; Kubota, Y.; Lattery, M.; ONeill, J.J.; Patton, S.; Poling, R.; Riehle, T.; Savinov, V.; Smith, A. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Severini, H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Blinov, S.; Duboscq, J.E.; Fujino, D.; Fulton, R.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P.; Wood, M. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P. [Purdue University, West Lafayette, Indiana 47907 (United States); Yurko, M.; Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Schaffner, S.F.; Ugolini, D.; Wang, R.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; Stroynowski, R.; Volobouev, I.; Ye, J. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Efimov, A.; Frasconi, F.; Gao, M.; Goldberg, M.; He, D.; Kopp, S.; Moneti, G.C.; Mountain, R.; Mukhin, Y.; Schuh, S.; Skwarnicki, T.; Stone, S.; Viehhauser, G.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; Jain, V.; and others
1997-06-01
We have measured the spectral shape Michel parameters {rho} and {eta} using leptonic decays of the {tau} , recorded by the CLEO II detector. Assuming e-{mu} universality in the vectorlike couplings, we find {rho}{sub e{mu}}=0.735{plus_minus}0.013{plus_minus}0.008 and {eta}{sub e{mu}}=-0.015{plus_minus}0.061{plus_minus}0.062 , where the first error is statistical and the second systematic. We also present measurements for the parameters for e and {mu} final states separately. {copyright} {ital 1997} {ital The American Physical Society}
Tangenciando o gesto autobiográfico em Michel Leiris e Herberto Helder
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Carolina Anglada de Rezende
2014-06-01
Full Text Available In position of the extensive discussion about the autobiography and its questioned status as a literary genre, this article aims to discuss the comparative gesture and his autobiographical traces in the works of two writers who, each in his own way, break the protocol associated with the writings of the self. In the foreground, it is the work A idade viril of Michel Leiris, in which writing, confession, memories and dreams merge, which will be compared to Photomaton & Vox, meeting of essays, reviews, poems and reports of the portuguese poet Herbert Helder.
The Michel parameter for the decay τ→eνanti ν
International Nuclear Information System (INIS)
Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Kloiber, T.; Koch, W.; Marsiske, H.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Maschmann, W.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Jakubowski, Z.; Muryn, B.; Nowak, G.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Peck, C.; Porter, F.C.; Ratoff, P.; Williams, D.A.; Karch, K.; Heimlich, F.H.
1989-01-01
The Crystal Ball detector at the Doris II storage ring at DESY has been used to study the electron energy spectrum of the decay τ→eνanti ν. In the standard model the Lorentz structure of the decay matrix element is of the well known V-A type, resulting in a Michel parameter of ρ=0.75. Our spectrum is found to be consistent with this value. A fit yields the value of 0.64±0.06±0.07. (orig.)
Universality of the quasinormal spectrum of near-extremal Kerr-Newman black holes
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)
2015-06-15
Our current knowledge about the quasinormal resonance spectrum of charged and rotating Kerr-Newman black holes is quite poor. This unsatisfactory situation is a direct consequence of the fact that all attempts to decouple the gravitational and electromagnetic perturbations of generic Kerr-Newman black holes have failed thus far. Recently, Zilhao et al. (Phys Rev D 90:12, 124088, 2014. arXiv:1410.0694) have studied the nonlinear stability of Kerr-Newman black holes. We show here that their numerical results for the time evolutions of the spacetime deformations of near-extremal Kerr-Newman black holes are described extremely well by a simple and universal analytical formula for the quasinormal resonances of the black holes. This formula is expressed in terms of the black-hole physical parameters: the horizon angular velocity Ω{sub H} and the Bekenstein-Hawking temperature T{sub BH}. (orig.)
Giant enhancement of Kerr rotation in two-dimensional Bismuth iron garnet/Ag photonic crystals
International Nuclear Information System (INIS)
Liang Hong; Zhang Qiang; Liu Huan; Fu Shu-Fang; Zhou Sheng; Wang Xuan-Zhang
2015-01-01
Kerr effects of two-dimensional (2D) Bismuth iron garnet (BIG)/Ag photonic crystals (PCs) combined magnetic and plasmonic functionalities is investigated with the effective medium theory. An analytical expression of Kerr rotation angles is derived, in which the effects of the surface pasmons polaritons (SPP) on magneto–optical (MO) activities are reflected. The largest enhancement of Kerr rotation up to now is demonstrated, which is improved three orders of magnitude compared with that of BIG film. When λ < 750 nm all of the reflection are over 10% for the arbitrary filling ratio f 1 , in addition, the enhancement of Kerr rotation angles are at least one order of magnitude. (paper)
How to observe a non-Kerr spacetime using gravitational waves.
Apostolatos, Theocharis A; Lukes-Gerakopoulos, Georgios; Contopoulos, George
2009-09-11
We present a generic criterion which can be used in gravitational-wave data analysis to distinguish an extreme-mass-ratio inspiral into a Kerr background spacetime from one into a non-Kerr spacetime. We exploit the fact that when an integrable system, such as the system that describes geodesic orbits in a Kerr spacetime, is perturbed, the tori in phase space which initially corresponded to resonances disintegrate so as to form Birkhoff chains on a surface of section. The KAM curves of the islands in such a chain share the same ratio of frequencies, even though the frequencies themselves vary from one KAM curve to another inside an island. However the KAM curves, which do not lie in a Birkhoff chain, do not share this characteristic property. Such a temporal constancy of the ratio of frequencies during the evolution of the gravitational-wave signal will signal a non-Kerr spacetime.
Transverse Kerr effect in one-dimensional magnetophotonic crystals: Experiment and theory
International Nuclear Information System (INIS)
Erokhin, S.; Boriskina, Yu.; Vinogradov, A.; Inoue, M.; Kobayashi, D.; Fedyanin, A.; Gan'shina, E.; Kochneva, M.; Granovsky, A.
2006-01-01
Magneto-optical transverse Kerr and Faraday effects are studied experimentally and theoretically in one-dimensional magnetophotonic crystals fabricated from a stack of four repetitions of layers of Bi-substituted yttrium iron garnet and SiO 2 layers. The results of theoretical calculations in the framework of modified matrices approach are consistent with the obtained experimental data with the exception of the one cusp at 480 nm in the transverse Kerr effect spectra. Possible mechanisms of this disagreement are discussed
Eruptive Massive Vector Particles of 5-Dimensional Kerr-Gödel Spacetime
Övgün, A.; Sakalli, I.
2018-02-01
In this paper, we investigate Hawking radiation of massive spin-1 particles from 5-dimensional Kerr-Gödel spacetime. By applying the WKB approximation and the Hamilton-Jacobi ansatz to the relativistic Proca equation, we obtain the quantum tunneling rate of the massive vector particles. Using the obtained tunneling rate, we show how one impeccably computes the Hawking temperature of the 5-dimensional Kerr-Gödel spacetime.
Il razzismo come strategia di difesa sociale. Michel Foucault e le forme attuali del biopotere
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Maura Simone
2010-01-01
Full Text Available Racism as a Social Defense Strategy. Michel Foucault and Current Forms of Biopower - During his lessons held at the College de France in 1976 Michel Foucault presents a genealogy of two types of narratives, concerning respectively war and race theory, considered in their historical development from the XVIth Century. Foucault’s work Il faut défendre la société outlines a specific model for the function of race theory, seen as a technique of normalization of diversity, and not longer as an “exceptional event” produced by the “totalitarian” narratives which arose in the XXth Century. This paper aims to stress the actuality of Foucault’s position, trying to show how the concept of bio-power, already at work in these lessons, deserves an active and productive role in the analysis of contemporary “democratic” societies, because of the structure of their internal cohesion, based on strategies developing “inclusion”/“exclusion” dynamics.
[A non-classical approach to medical practices: Michel Foucault and Actor-Network Theory].
Bińczyk, E
2001-01-01
The text presents an analysis of medical practices stemming from two sources: Michel Foucault's conception and the research of Annemarie Mol and John Law, representatives of a trend known as Actor-Network Theory. Both approaches reveal significant theoretical kinship: they can be successfully consigned to the framework of non-classical sociology of science. I initially refer to the cited conceptions as a version of non-classical sociology of medicine. The identity of non-classical sociology of medicine hinges on the fact that it undermines the possibility of objective definitions of disease, health and body. These are rather approached as variable social and historical phenomena, co-constituted by medical practices. To both Foucault and Mol the main object of interest was not medicine as such, but rather the network of medical practices. Mol and Law sketch a new theoretical perspective for the analysis of medical practices. They attempt to go beyond the dichotomous scheme of thinking about the human body as an object of medical research and the subject of private experience. Research on patients suffering blood-sugar deficiency provide the empirical background for the thesis of Actor-Network Theory representatives. Michel Foucault's conceptions are extremely critical of medical practices. The French researcher describes the processes of 'medicalising' Western society as the emergence of a new type of power. He attempts to sensitise the reader to the ethical dimension of the processes of medicalising society.
Banki-Michell Optimal Design by Computational Fluid Dynamics Testing and Hydrodynamic Analysis
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Tullio Tucciarelli
2013-04-01
Full Text Available In hydropower, the exploitation of small power sources requires the use of small turbines that combine efficiency and economy. Banki-Michell turbines represent a possible choice for their simplicity and for their good efficiency under variable load conditions. Several experimental and numerical tests have already been designed for examining the best geometry and optimal design of cross-flow type machines, but a theoretical framework for a sequential design of the turbine parameters, taking full advantage of recently expanded computational capabilities, is still missing. To this aim, after a review of the available criteria for Banki-Michell parameter design, a novel two-step procedure is described. In the first step, the initial and final blade angles, the outer impeller diameter and the shape of the nozzle are selected using a simple hydrodynamic analysis, based on a very strong simplification of reality. In the second step, the inner diameter, as well as the number of blades and their shape, are selected by testing single options using computational fluid dynamics (CFD simulations, starting from the suggested literature values. Good efficiency is attained not only for the design discharge, but also for a large range of variability around the design value.
Analytical study of a Kerr-Sen black hole and a charged massive scalar field
Bernard, Canisius
2017-11-01
It is reported that Kerr-Newman and Kerr-Sen black holes are unstable to perturbations of charged massive scalar field. In this paper, we study analytically the complex frequencies which characterize charged massive scalar fields in a near-extremal Kerr-Sen black hole. For near-extremal Kerr-Sen black holes and for charged massive scalar fields in the eikonal large-mass M ≫μ regime, where M is the mass of the black hole, and μ is the mass of the charged scalar field, we have obtained a simple expression for the dimensionless ratio ωI/(ωR-ωc) , where ωI and ωR are, respectively, the imaginary and real parts of the frequency of the modes, and ωc is the critical frequency for the onset of super-radiance. We have also found our expression is consistent with the result of Hod [Phys. Rev. D 94, 044036 (2016), 10.1103/PhysRevD.94.044036] for the case of a near-extremal Kerr-Newman black hole and the result of Zouros and Eardly [Ann. Phys. (N.Y.) 118, 139 (1979), 10.1016/0003-4916(79)90237-9] for the case of neutral scalar fields in the background of a near-extremal Kerr black hole.
Notes on constraints for the observation of Polar Kerr Effect in complex materials
International Nuclear Information System (INIS)
Kapitulnik, Aharon
2015-01-01
While Kerr effect has been used extensively for the study of magnetic materials, it is only recently that its has shown to be a powerful tool for the study of more complex quantum matter. Since such materials tend to exhibit a wealth of new phases and broken symmetries, it is important to understand the general constraints on the possibility of observing a finite Kerr effect. In this paper we reviewed the consequences of reciprocity on the scattering of electromagnetic waves. In particular we concentrate on the possible detection of Kerr effect from chiral media with and without time-reversal symmetry breaking. We show that a finite Kerr effect is possible only if reciprocity is broken. Introducing the utilization of the Sagnac interferometer as a detector for breakdown of reciprocity via the detection of a finite Kerr effect, we argue that in the linear regime, a finite detection is possible only if reciprocity is broken. We then discuss possible Kerr effect detection for materials with natural optical activity, magnetism, and chiral superconductivity
Notes on constraints for the observation of Polar Kerr Effect in complex materials
Energy Technology Data Exchange (ETDEWEB)
Kapitulnik, Aharon, E-mail: aharonk@stanford.edu [Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
2015-03-01
While Kerr effect has been used extensively for the study of magnetic materials, it is only recently that its has shown to be a powerful tool for the study of more complex quantum matter. Since such materials tend to exhibit a wealth of new phases and broken symmetries, it is important to understand the general constraints on the possibility of observing a finite Kerr effect. In this paper we reviewed the consequences of reciprocity on the scattering of electromagnetic waves. In particular we concentrate on the possible detection of Kerr effect from chiral media with and without time-reversal symmetry breaking. We show that a finite Kerr effect is possible only if reciprocity is broken. Introducing the utilization of the Sagnac interferometer as a detector for breakdown of reciprocity via the detection of a finite Kerr effect, we argue that in the linear regime, a finite detection is possible only if reciprocity is broken. We then discuss possible Kerr effect detection for materials with natural optical activity, magnetism, and chiral superconductivity.
Photon motion in Kerr-de Sitter spacetimes
Energy Technology Data Exchange (ETDEWEB)
Charbulak, Daniel; Stuchlik, Zdenek [Silesian University in Opava, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Opava (Czech Republic)
2017-12-15
We study the general motion of photons in the Kerr-de Sitter black-hole and naked singularity spacetimes. The motion is governed by the impact parameters X, related to the axial symmetry of the spacetime, and q, related to its hidden symmetry. Appropriate 'effective potentials' governing the latitudinal and radial motion are introduced and their behavior is examined by the 'Chinese boxes' technique giving regions allowed for the motion in terms of the impact parameters. Restrictions on the impact parameters X and q are established in dependence on the spacetime parameters M, Λ, a. The motion can be of orbital type (crossing the equatorial plane, q > 0) and vortical type (tied above or below the equatorial plane, q < 0). It is shown that for negative values of q, the reality conditions imposed on the latitudinal motion yield stronger constraints on the parameter X than that following from the reality condition of the radial motion, excluding the existence of vortical motion of constant radius. The properties of the spherical photon orbits of the orbital type are determined and used along with the properties of the effective potentials as criteria of classification of the KdS spacetimes according to the properties of the motion of the photon. (orig.)
Neutrino oscillations in the Kerr-Newman spacetime
International Nuclear Information System (INIS)
Ren Jun; Zhang Chengmin
2010-01-01
The mass neutrino oscillation in the Kerr-Newman (K-N) spacetime is studied in the plane θ = θ 0 , and general equations of the oscillation phases are given. The effect of the rotation and electric charge on the phase is presented. Then, we consider three special cases. (1) The neutrinos travel along the geodesics with angular momentum L = aE in the equatorial plane. (2) The neutrinos travel along the geodesics with L = 0 in the equatorial plane. (3) The neutrinos travel along the radial geodesics in the direction θ = 0. Finally, we calculate the proper oscillation length in the K-N spacetime. The effect of the gravitational field on the oscillation length is embodied in the gravitational red shift factor. When the neutrino travels out of the gravitational field, a blue shift of the oscillation length takes place. We discuss the variation of the oscillation length influenced by the gravitational field strength, the rotation a 2 and charge Q.
3-D collapse of rotating stars to Kerr black holes
International Nuclear Information System (INIS)
Baiotti, L; Hawke, I; Montero, P J; Loeffler, F L; Rezzolla, L; Stergioulas, N; Font, J A; Seidel, E
2005-01-01
We study gravitational collapse of uniformly rotating neutron stars to Kerr black holes, using a new three-dimensional, fully general relativistic hydrodynamics code, which uses high-resolution shock-capturing techniques and a conformal traceless formulation of the Einstein equations. We investigate the gravitational collapse by carefully studying not only the dynamics of the matter, but also that of the trapped surfaces, i.e. of both the apparent and event horizons formed during the collapse. The use of these surfaces, together with the dynamical horizon framework, allows for a precise measurement of the black-hole mass and spin. The ability to successfully perform these simulations for sufficiently long times relies on excising a region of the computational domain which includes the singularity and is within the apparent horizon. The dynamics of the collapsing matter is strongly influenced by the initial amount of angular momentum in the progenitor star and, for initial models with sufficiently high angular velocities, the collapse can lead to the formation of an unstable disc in differential rotation
UN ETHOS HISTORICO La historia en los últimos trabajos de Michel Foucault.
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Luis César Sanfelippo
2016-06-01
Full Text Available En el presente texto, se indagará la concepción de la historia presente en los últimos trabajos de Michel Foucault. Estos trabajos se inscriben en un contexto de crisis del régimen moderno de historicidad, centrado en las ideas de progreso y de revolución. Intentaremos demostrar que, en dicho contexto, la obra del filósofo francés permitiría abordar una relación diferente entre la práctica intelectual y las prácticas de resistencia, entre la labor historiográfica y unos modos de vida que, en el presente, permitirían una transformación de lo que somos.
The Desire for Knowledge as an Incentive for Life in Community, following Michel de Montaigne
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Víctor H. Palacios Cruz
2015-12-01
Full Text Available A tendency towards truth indicates an inclination towards being in tune with the world and inserting one’s own life within it. It is a process that requires the concurrence of other viewpoints, fragmentary and diverse, the incorporation of which ensures the objectivity of knowledge and respects the richness of what it is real. Knowledge requires habits of coexistence and communication that establish a common space for equality and plurality in exchanges. Michel de Montaigne, in the troubled sixteenth century, celebrated the pleasure of discussion and exhorted people to travel as a form of avoiding personal pride and increasing their being through the encounter. A loyal search for truth in conjunction with courtesy in controversy would entail the promotion of civic virtues beyond mere tolerance and bring about attitudes of mutual interest, cordiality, dialogue, inclusion and care for that which is common.
MICHEL FOUCAULT AND THE FINANCIAL GOVERNABILITY REFLECTIONS ON THE INTERNATIONAL FINANCIAL CRISIS
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Juan Omar, Agüero
2010-01-01
Full Text Available In this paper I present a governability or power technology form what I call financial governability that differs from the German ordoliberalism and the North American anacor-liberalism, analyzed by Michel Foucault. In which context does this form emerge from financial rationality?, how does it emerge and develop itself?, what meanings has it got for biopolítics and governability? And what implications happen from this transformation process of the human work in financial capital?, these are some of the matters that are discussed in this paper. As from the concepts of biopolítics and governability, I treat the theories of the policy of society and human capital, as foundations of the German ordoliberalism and the North American anarco-liberalism, respectively, later discussing the governability form which I call financial governability, as power technology differentiated from those.
Histoire de la traduction au XXe siècle : l’apport de Michel Ballard
Prado Paz, Carlos de
2015-01-01
Este trabajo tiene como temática “la historia de la traducción en el siglo XX”, y más en concreto la aportación de una de las figuras más importantes de la traducción en Francia, Michel Ballard. A lo largo del trabajo expondré la obra y pensamiento de Ballard, centrándome en temas como la traducción, su historia, la relación entre traducción y traductología, o la importancia del contacto entre culturas y lenguas. El fallecimiento en el transcurso de nuestro trabajo de esta figura cumbre...
Bartolomé de las Casas y Michel de Montaigne: Escritura y lectura del Nuevo Mundo
Juan Durán Luzio
2016-01-01
Se trata de mostrar cómo la obra de Bartolomé de Las Casas, Brevísima relación de la destrucción de las Indias, publicada en 1552 y traducida al francés en 1579,fue leída por Michel de Montaigne e incorporada en sus párrafos y doctrinas más relevantes en sus dos ensayos sobre el Nuevo Mundo: "Des Cannibales" (1580) y "Des Coches" (1588). The work of Bartolomé de Las Casas Brevísima relación de la destrucción de las Indias, published in 1552 and translated into French in 1579, is sho...
Relación social y teoría de las formas en Michel Maffesoli
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Manuel Herrera Gómez
2003-01-01
Full Text Available La sociología de Michel Maffesoli se ocupa principalmente de las potencialidades polimórficas de los singulares individuos. Su teoría "postmoderna", centrada en el tránsito del homo politicus-oeconomicus al homo aestheticus, representa la exaltación de nuestros sentimientos individuales, de nuestras emociones, de nuestros deseos para reconstruir pequeñas tribus comunitarias en una sociedad que solamente trata de imponer sus cánones funcionales. En una palabra, se tata de rehabilitar nuestro obrar espontáneo, dionisíaco, contra el poder, siempre abstracto y mecánico, de la sociedad.
Geometry, analysis and probability in honor of Jean-Michel Bismut
Hofer, Helmut; Labourie, François; Jan, Yves; Ma, Xiaonan; Zhang, Weiping
2017-01-01
This volume presents original research articles and extended surveys related to the mathematical interest and work of Jean-Michel Bismut. His outstanding contributions to probability theory and global analysis on manifolds have had a profound impact on several branches of mathematics in the areas of control theory, mathematical physics and arithmetic geometry. Contributions by: K. Behrend N. Bergeron S. K. Donaldson J. Dubédat B. Duplantier G. Faltings E. Getzler G. Kings R. Mazzeo J. Millson C. Moeglin W. Müller R. Rhodes D. Rössler S. Sheffield A. Teleman G. Tian K-I. Yoshikawa H. Weiss W. Werner The collection is a valuable resource for graduate students and researchers in these fields.
STS-93 M.S. Michel Tognini suits up before launch
1999-01-01
For the third time, in the Operations and Checkout Building, STS- 93 Mission Specialist Michel Tognini of France, who represents the Centre National d'Etudes Spatiales (CNES), waves after donning his launch and entry suit during final launch preparations. After Space Shuttle Columbia's July 20 and 22 launch attempts were scrubbed, the launch was again rescheduled for Friday, July 23, at 12:24 a.m. EDT. STS-93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The STS-93 crew numbers five: Commander Eileen M. Collins, Pilot Jeffrey S. Ashby, and Mission Specialists Stephen A. Hawley (Ph.D.), Catherine G. Coleman (Ph.D.) and Tognini. Collins is the first woman to serve as commander of a shuttle mission.
A psicologia em História da Loucura de Michel Foucault
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Fernando de Almeida Silveira
2009-04-01
Full Text Available Michel Foucault investiga "a história das relações que o pensamento mantém com a verdade" e desnaturaliza corpo, alma e psiqué considerando-os invenções histórico-discursivas, as quais só têm sentido se inseridas em determinados arranjos epistêmicos de produção de verdades, no caso, o surgimento das ciências humanas. Esta pesquisa estuda a ordem do discurso foucaultiano sobre a Psicologia em sua fase arqueológica, no livro História da Loucura, com o intuito de oferecer subsídios para a compreensão da história dos discursos da Psicologia, no que se refere à edificação do sujeito e do objeto psicológicos e em seus efeitos subjetivadores.
The non-place as a tourist destination in Michel Houellebecq’s Plateforme
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Ana Filipa Prata
2014-11-01
Full Text Available This paper discusses the representation of mass tourism in Michel Houellebecq’s Plateform (2001 in relation to the concept of “non-place” defining the “supermodern” spaces proliferating in the globalized world deprived from historical, identitary and relational values. As the universe of tourism is the central element of the novel’s plot, we shall look at how it takes the form of a dysphoric configuration of a certain idea of travel, and how the language of simulacra, in which hotels airports constitute transfer platforms of the same capitalistic order, is sustaining it. Through the analysis of the production and consumption mechanisms of adventure circuits and vacation clubs, that slip inside the field of sexual tourism in Thailand, this book exposes ironically an alienated occidental society looking for an escape to everyday life in exotic destinations and à la carte sojourns.
Lungo le vie di pellegrinaggio: la lezione astronomica di Gerberto a San Michele della Chiusa
Paladino, Laura C.
A pilgrim on the trails of the Earth: that's how Gerbertus appears to us in the years preceding his pontificate as well in those, brief and intense, in which he was Pope. An ardent pilgrim of faith moved at the same time by vast intellectual interests that allowed him to come into contact with the most important schools of the time, of any cultural tradition; a pilgrim full of love, willing to transmit the enormous heritage of faith and knowledge of which he was custodian. The presence of the illustrious Benedictine is not explicitly documented in the Abbey of San Michele della Chiusa, but the signs of its cultural and ideological influence are evident both in historical memory as in the artistical vestiges of the Sacra: we investigate here, this presence, authoritative, original and versatile, to outline another aspect, still little investigated, of the lesson of Gerbert, monk, scientist, teacher and pastor.
Michel de Certeau and the Admirabile Commercium of Meanings in Education
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Fabio Botelho Josgrilberg
2008-07-01
Full Text Available This paper aims at reflecting upon Michel de Certeau’s relationship with education. Even though the issue is marginal to his other fields of interest, such as history, religion and culture, the challenges he presents are inspiring for educators at varying levels and from different fields of knowledge. Certeau’s thought moving power is the movement towards other ones, fostered by ethical and epistemological demands; a movement which opens itself to the possibility that each encounter may reveal something new. The movement is born from the refusal of literal meanings or existing hierarchies, without falling into irresponsible relativism which denies his own memory. With Certeau we learn to see schools or universities as places of crossing paths, bricolage and operations which escape from established references.
Ferreira, Hugo R. C.; Herdeiro, Carlos A. R.
2018-04-01
It has been recently observed that a scalar field with Robin boundary conditions (RBCs) can trigger both a superradiant and a bulk instability for a Bañados-Teitelboim-Zanelli (BTZ) black hole (BH) [1]. To understand the generality and scrutinize the origin of this behavior, we consider here the superradiant instability of a Kerr BH confined either in a mirrorlike cavity or in anti-de Sitter (AdS) space, triggered also by a scalar field with RBCs. These boundary conditions are the most general ones that ensure the cavity/AdS space is an isolated system and include, as a particular case, the commonly considered Dirichlet boundary conditions (DBCs). Whereas the superradiant modes for some RBCs differ only mildly from the ones with DBCs, in both cases, we find that as we vary the RBCs the imaginary part of the frequency may attain arbitrarily large positive values. We interpret this growth as being sourced by a bulk instability of both confined geometries when certain RBCs are imposed to either the mirrorlike cavity or the AdS boundary, rather than by energy extraction from the BH, in analogy with the BTZ behavior.
Micheller, Reinhard, 1977-
2013-01-01
EKA arhitektuuri ja linnaplaneerimise osakonna III kursuse 2009-2012 aastail erialase projekteerimise ülesande raames on vestlusringis maastikuarhitektuurse osa juhendajad Reinhard Micheller ja Günther Schalk (michellerundschalk, München) ning Katrin Koov (KAVAKAVA, EKA maastikuarhitektuuri õppekava juht)
Miller, Peter M.
2012-01-01
As a distinguished scholar over the past 45 years, Michel Hersen has left an indelible mark on the field of behavior therapy and clinical psychology. One of his most enduring legacies is his early research work in the area of social skills assessment and training, with special attention to assertiveness training. His basic analogue and clinical…
Enhancement of optical Kerr effect in quantum-cascade lasers with multiple resonance levels.
Bai, Jing; Citrin, D S
2008-08-18
In this paper, we investigated the optical Kerr lensing effect in quantum-cascade lasers with multiple resonance levels. The Kerr refractive index n2 is obtained through the third-order susceptibility at the fundamental frequency chi(3)( omega; omega, omega,-omega). Resonant two-photon processes are found to have almost equal contributions to chi(3)( omega; omega, omega,-omega) as the single-photon processes, which result in the predicted enhancement of the positive nonlinear (Kerr) refractive index, and thus may enhance mode-locking of quantum-cascade lasers. Moreover, we also demonstrate an isospectral optimization strategy for further improving n2 through the band-structure design, in order to boost the multimode performance of quantum-cascade lasers. Simulation results show that the optimized stepwise multiple-quantum-well structure has n2 approximately 10-8 cm2/W, a twofold enhancement over the original flat quantum-well structure. This leads to a refractive-index change (delta)n of about 0.01, which is at the upper bound of those reported for typical Kerr medium. This stronger Kerr refractive index may be important for quantum-cascade lasers ultimately to demonstrate self-mode-locking.
Strong gravitational lensing by a Konoplya-Zhidenko rotating non-Kerr compact object
Energy Technology Data Exchange (ETDEWEB)
Wang, Shangyun; Chen, Songbai; Jing, Jiliang, E-mail: shangyun_wang@163.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)
2016-11-01
Konoplya and Zhidenko have proposed recently a rotating non-Kerr black hole metric beyond General Relativity and make an estimate for the possible deviations from the Kerr solution with the data of GW 150914. We here study the strong gravitational lensing in such a rotating non-Kerr spacetime with an extra deformation parameter. We find that the condition of existence of horizons is not inconsistent with that of the marginally circular photon orbit. Moreover, the deflection angle of the light ray near the weakly naked singularity covered by the marginally circular orbit diverges logarithmically in the strong-field limit. In the case of the completely naked singularity, the deflection angle near the singularity tends to a certain finite value, whose sign depends on the rotation parameter and the deformation parameter. These properties of strong gravitational lensing are different from those in the Johannsen-Psaltis rotating non-Kerr spacetime and in the Janis-Newman-Winicour spacetime. Modeling the supermassive central object of the Milk Way Galaxy as a Konoplya-Zhidenko rotating non-Kerr compact object, we estimated the numerical values of observables for the strong gravitational lensing including the time delay between two relativistic images.
Genetic optimization of magneto-optic Kerr effect in lossy cavity-type magnetophotonic crystals
Energy Technology Data Exchange (ETDEWEB)
Ghanaatshoar, M., E-mail: m-ghanaat@cc.sbu.ac.i [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin 1983963113, Tehran (Iran, Islamic Republic of); Alisafaee, H. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin 1983963113, Tehran (Iran, Islamic Republic of)
2011-07-15
We have demonstrated an optimization approach in order to obtain desired magnetophotonic crystals (MPCs) composed of a lossy magnetic layer (TbFeCo) placed within a multilayer structure. The approach is an amalgamation between a 4x4 transfer matrix method and a genetic algorithm. Our objective is to enhance the magneto-optic Kerr effect of TbFeCo at short visible wavelength of 405 nm. Through the optimization approach, MPC structures are found meeting definite criteria on the amount of reflectivity and Kerr rotation. The resulting structures are fitted more than 99.9% to optimization criteria. Computation of the internal electric field distribution shows energy localization in the vicinity of the magnetic layer, which is responsible for increased light-matter interaction and consequent enhanced magneto-optic Kerr effect. Versatility of our approach is also exhibited by examining and optimizing several MPC structures. - Research highlights: Structures comprising a highly absorptive TbFeCo layer are designed to work for data storage applications at 405 nm. Optimization algorithm resulted in structures fitted 99.9% to design criteria. More than 10 structures are found exhibiting magneto-optical response of about 1{sup o} rotation and 20% reflection. The ratio of the Kerr rotation to the Kerr ellipticity is enhanced by a factor of 30.
Effective stability against superradiance of Kerr black holes with synchronised hair
Degollado, Juan Carlos; Herdeiro, Carlos A. R.; Radu, Eugen
2018-06-01
Kerr black holes with synchronised hair [1,2] are a counter example to the no hair conjecture, in General Relativity minimally coupled to simple matter fields (with mass μ) obeying all energy conditions. Since these solutions have, like Kerr, an ergoregion it has been a lingering possibility that they are afflicted by the superradiant instability, the same process that leads to their dynamical formation from Kerr. A recent breakthrough [3] confirmed this instability and computed the corresponding timescales for a sample of solutions. We discuss how these results and other observations support two conclusions: 1) starting from the Kerr limit, the increase of hair for fixed coupling μM (where M is the BH mass) increases the timescale of the instability; 2) there are hairy solutions for which this timescale, for astrophysical black hole masses, is larger than the age of the Universe. The latter conclusion introduces the limited, but physically relevant concept of effective stability. The former conclusion, allows us to identify an astrophysically viable domain of such effectively stable hairy black holes, occurring, conservatively, for Mμ ≲ 0.25. These are hairy BHs that form dynamically, from the superradiant instability of Kerr, within an astrophysical timescale, but whose own superradiant instability occurs only in a cosmological timescale.
Stray-field-induced Faraday contributions in wide-field Kerr microscopy and -magnetometry
International Nuclear Information System (INIS)
Markó, D.; Soldatov, I.; Tekielak, M.; Schäfer, R.
2015-01-01
The magnetic domain contrast in wide-field Kerr microscopy on bulk specimens can be substantially distorted by non-linear, field-dependent Faraday rotations in the objective lens that are caused by stray-field components emerging from the specimen. These Faraday contributions, which were detected by Kerr-magnetometry on grain-oriented iron–silicon steel samples, are thoroughly elaborated and characterized. They express themselves as a field-dependent gray-scale offset to the domain contrast and in highly distorted surface magnetization curves if optically measured in a wide field Kerr microscope. An experimental method to avoid such distortions is suggested. In the course of these studies, a low-permeability part in the surface magnetization loop of slightly misoriented (110)-surfaces in iron–silicon sheets was discovered that is attributed to demagnetization effects in direction perpendicular to the sheet surface. - Highlights: • Magnetizing a finite sample in a Kerr microscope leads to sample-generated stray-fields. • They cause non-linear, field- and position-dependent Faraday rotations in the objective. • This leads to a modulation of the Kerr contrast and to distorted MOKE loops. • A method to compensate these Faraday rotations is presented
Numerical investigation of the late-time Kerr tails
Energy Technology Data Exchange (ETDEWEB)
Racz, Istvan; Toth, Gabor Zs, E-mail: iracz@rmki.kfki.hu, E-mail: tgzs@rmki.kfki.hu [RMKI, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)
2011-10-07
The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I{sup +} are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I{sup +}. The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.
Numerical investigation of the late-time Kerr tails
International Nuclear Information System (INIS)
Racz, Istvan; Toth, Gabor Zs
2011-01-01
The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I + are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I + . The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.
Ahmad, S.; Ahmad, A.; Bacha, B. A.; Khan, A. A.; Abdul Jabar, M. S.
2017-12-01
Surface Plasmon Polaritons (SPPs) are theoretically investigated at the interface of a dielectric metal and gold. The output pulse from the dielectric is used as the input pulse for the generation of SPPs. The SPPs show soliton-like behavior at the interface. The solitary form of a SPP is maintained under the effects of Kerr nonlinearity, Doppler broadening and Fresnel dragging whereas its phase shift is significantly modified. A 0.3radian phase shift is calculated in the presence of both Kerr nonlinearity and Fresnel dragging in the absence of plasma motion. The phase shift is enhanced to 60radian due to the combined effect of Doppler broadening, Kerr nonlinearity and Fresnel dragging. The results may have significant applications in nano-photonics, optical tweezers, photovoltaic devices, plasmonster and sensing technology.
Researching on Hawking Effect in a Kerr Space Time via Open Quantum System Approach
International Nuclear Information System (INIS)
Liu, Wen-Biao; Liu, Xian-Ming
2014-01-01
It has been proposed that Hawking radiation from a Schwarzschild or a de Sitter spacetime can be understood as the manifestation of thermalization phenomena in the framework of an open quantum system. Through examining the time evolution of a detector interacting with vacuum massless scalar fields, it is found that the detector would spontaneously excite with a probability the same as the thermal radiation at Hawking temperature. Following the proposals, the Hawking effect in a Kerr space time is investigated in the framework of an open quantum systems. It is shown that Hawking effect of the Kerr space time can also be understood as the the manifestation of thermalization phenomena via open quantum system approach. Furthermore, it is found that near horizon local conformal symmetry plays the key role in the quantum effect of the Kerr space time
Advanced magneto-optical Kerr effect measurements of superconductors at low temperatures
Directory of Open Access Journals (Sweden)
Claudia Stahl
2017-10-01
Full Text Available Magneto-optical Kerr-effect (MOKE measurements of superconducting films with soft-magnetic coatings are performed at low temperatures using a laser-based MOKE set-up. An elaborate measurement scheme with internal reference allows the quantitative comparison of the temperature dependent Kerr-amplitude with the magnetic field generated by supercurrents. For this purpose, an amorphous CoFeB thin film exhibiting a large Kerr-signal is deposited directly on top of the YBCO superconductor acting as field sensing layer. It is shown that the resulting magnetic hysteresis loops of the soft-magnetic film can be used to reconstruct the electric properties of the superconductor.
Magneto-optical fingerprints of distinct graphene multilayers using the giant infrared Kerr effect
Ellis, Chase T.; Stier, Andreas V.; Kim, Myoung-Hwan; Tischler, Joseph G.; Glaser, Evan R.; Myers-Ward, Rachael L.; Tedesco, Joseph L.; Eddy, Charles R.; Gaskill, D. Kurt; Cerne, John
2013-11-01
The remarkable electronic properties of graphene strongly depend on the thickness and geometry of graphene stacks. This wide range of electronic tunability is of fundamental interest and has many applications in newly proposed devices. Using the mid-infrared, magneto-optical Kerr effect, we detect and identify over 18 interband cyclotron resonances (CR) that are associated with ABA and ABC stacked multilayers as well as monolayers that coexist in graphene that is epitaxially grown on 4H-SiC. Moreover, the magnetic field and photon energy dependence of these features enable us to explore the band structure, electron-hole band asymmetries, and mechanisms that activate a CR response in the Kerr effect for various multilayers that coexist in a single sample. Surprisingly, we find that the magnitude of monolayer Kerr effect CRs is not temperature dependent. This unexpected result reveals new questions about the underlying physics that makes such an effect possible.
Dynamical Formation of Kerr Black Holes with Synchronized Hair: An Analytic Model.
Herdeiro, Carlos A R; Radu, Eugen
2017-12-29
East and Pretorius have successfully evolved, using fully nonlinear numerical simulations, the superradiant instability of the Kerr black hole (BH) triggered by a massive, complex vector field. Evolutions terminate in stationary states of a vector field condensate synchronized with a rotating BH horizon. We show that these end points are fundamental states of Kerr BHs with synchronized Proca hair. Motivated by the "experimental data" from these simulations, we suggest a universal (i.e., field-spin independent), analytic model for the subset of BHs with synchronized hair that possess a quasi-Kerr horizon, applicable in the weak hair regime. Comparing this model with fully nonlinear numerical solutions of BHs with a synchronized scalar or Proca hair, we show that the model is accurate for hairy BHs that may emerge dynamically from superradiance, whose domain we identify.
Super-entropic black holes and the Kerr-CFT correspondence
Energy Technology Data Exchange (ETDEWEB)
Sinamuli, Musema [Department of Physics and Astronomy, University of Waterloo,200 University Ave., Waterloo, Ontario N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics,31 Caroline St., Waterloo, Ontario, N2L 2Y5 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,200 University Ave., Waterloo, Ontario N2L 3G1 (Canada)
2016-08-24
We demonstrate that Kerr-CFT duality can be extended to super-entropic black holes, which have non-compact horizons with finite area. We demonstrate that this duality is robust insofar as the ultra-spinning limit of a Kerr-AdS black hole (which yields the super-entropic class) commutes with the near-horizon limit (which yields the Kerr-CFT duality). Consequently the Bekenstein-Hawking and the CFT entropies are equivalent. We show that the duality holds for both singly-spinning super-entropic black holes in 4 dimensions and for doubly-spinning super-entropic black holes of gauged supergravity in 5 dimensions. In both cases we obtain not only the expected left/right temperatures, but also temperatures associated with electric charge and with a new thermodynamic parameter specific to super-entropic black holes.
Super-entropic black holes and the Kerr-CFT correspondence
International Nuclear Information System (INIS)
Sinamuli, Musema; Mann, Robert B.
2016-01-01
We demonstrate that Kerr-CFT duality can be extended to super-entropic black holes, which have non-compact horizons with finite area. We demonstrate that this duality is robust insofar as the ultra-spinning limit of a Kerr-AdS black hole (which yields the super-entropic class) commutes with the near-horizon limit (which yields the Kerr-CFT duality). Consequently the Bekenstein-Hawking and the CFT entropies are equivalent. We show that the duality holds for both singly-spinning super-entropic black holes in 4 dimensions and for doubly-spinning super-entropic black holes of gauged supergravity in 5 dimensions. In both cases we obtain not only the expected left/right temperatures, but also temperatures associated with electric charge and with a new thermodynamic parameter specific to super-entropic black holes.
Flat-space holography and stress tensor of Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Baghchesaraei, Omid, E-mail: omidbaghchesaraei@gmail.com [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Fareghbal, Reza, E-mail: r_fareghbal@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Izadi, Yousef, E-mail: yizadi2015@fau.edu [Department of Physics, Florida Atlantic University, Boca Raton, FL 33431 (United States)
2016-09-10
We propose a stress tensor for the Kerr black hole written in the Boyer–Lindquist coordinate. To achieve this, we use the dictionary of the Flat/CCFT correspondence and take the flat-space limit from the quasi-local stress tensor of the four-dimensional Kerr–AdS black hole. The proposed stress tensor yields the correct values for the mass and angular momentum of the Kerr black hole at spatial infinity. We also calculate some components of the energy momentum tensor of the three dimensional CCFT and show that they are consistent with the holographic calculation of the Kerr black hole. The calculation we present in this paper is another confirmation for the Flat/CCFT proposal.
Schlick, Michael Christian; Kapernaum, Nadia; Neidhardt, Manuel; Wöhrle, Tobias; Stöckl, Yannick; Laschat, Sabine; Gießelmann, Frank
2018-06-06
The electro-optic Kerr effect in the isotropic phase of two ionic liquid crystals (ILCs) is investigated and compared to the Kerr effect in non-ionic liquid crystals (LCs) with same phase sequences, namely direct isotropic to hexagonal columnar transitions and direct isotropic to smectic-A transitions. Up to electric field amplitudes of some 106 V m-1, the optical birefringence induced in the isotropic phases follows Kerr's law and strongly increases when the temperature approaches the transition temperature into the particular liquid crystalline phase. Close to the transition, maximum Kerr constants in the order of 10-11 m V-2 are found, which are more than ten times higher than the Kerr constant of nitrobenzene, a strongly dipolar fluid with a huge Kerr effect applied in optical shutters and phase modulators. In comparison to their non-ionic LC counterparts the Kerr effect in ILCs is found to be enhanced in magnitude, but slowed-down in speed, showing rise times in the order of ten milliseconds. These remarkable differences are attributed to the presence of counterion polarization well-known from complex ionic fluids such as polyelectrolytes or ionic micellar solutions. ILCs thus combine the Kerr effect features of liquid crystals and complex ionic fluids. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Designing Kerr interactions using multiple superconducting qubit types in a single circuit
Elliott, Matthew; Joo, Jaewoo; Ginossar, Eran
2018-02-01
The engineering of Kerr interactions is of great interest for processing quantum information in multipartite quantum systems and for investigating many-body physics in a complex cavity-qubit network. We study how coupling multiple different types of superconducting qubits to the same cavity modes can be used to modify the self- and cross-Kerr effects acting on the cavities and demonstrate that this type of architecture could be of significant benefit for quantum technologies. Using both analytical perturbation theory results and numerical simulations, we first show that coupling two superconducting qubits with opposite anharmonicities to a single cavity enables the effective self-Kerr interaction to be diminished, while retaining the number splitting effect that enables control and measurement of the cavity field. We demonstrate that this reduction of the self-Kerr effect can maintain the fidelity of coherent states and generalised Schrödinger cat states for much longer than typical coherence times in realistic devices. Next, we find that the cross-Kerr interaction between two cavities can be modified by coupling them both to the same pair of qubit devices. When one of the qubits is tunable in frequency, the strength of entangling interactions between the cavities can be varied on demand, forming the basis for logic operations on the two modes. Finally, we discuss the feasibility of producing an array of cavities and qubits where intermediary and on-site qubits can tune the strength of self- and cross-Kerr interactions across the whole system. This architecture could provide a way to engineer interesting many-body Hamiltonians and be a useful platform for quantum simulation in circuit quantum electrodynamics.
A re-examination of the life and work of A.F.G. Kerr and of his colleagues and friends
DEFF Research Database (Denmark)
Parnell, J. A. N.; Pilla, F.; Simpson, D. A.
2015-01-01
Arthur Francis George Kerr's life is reviewed and related to a previously published account. Kerr's collecting activity is analysed using an expanded version of the Thai Biogeography Group's database of collections. 8,666 of the total 48,970 collections are Kerr's and 3,178 are those of his colle...
Transverse Kerr effect in one-dimensional magnetophotonic crystals: Experiment and theory
Energy Technology Data Exchange (ETDEWEB)
Erokhin, S. [Faculty of Physics, Lomonosov Moscow State University, 11992 Moscow (Russian Federation)]. E-mail: yerokhin@magn.ru; Boriskina, Yu. [Faculty of Physics, Lomonosov Moscow State University, 11992 Moscow (Russian Federation); Vinogradov, A. [Institute for Theoretical and Applied Electrodynamics, Izhorskaya 13/19, 127412 Moscow (Russian Federation); Inoue, M. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi 441-8580 (Japan); Kobayashi, D. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi 441-8580 (Japan); Fedyanin, A. [Faculty of Physics, Lomonosov Moscow State University, 11992 Moscow (Russian Federation); Gan' shina, E. [Faculty of Physics, Lomonosov Moscow State University, 11992 Moscow (Russian Federation); Kochneva, M. [Faculty of Physics, Lomonosov Moscow State University, 11992 Moscow (Russian Federation); Granovsky, A. [Faculty of Physics, Lomonosov Moscow State University, 11992 Moscow (Russian Federation)
2006-05-15
Magneto-optical transverse Kerr and Faraday effects are studied experimentally and theoretically in one-dimensional magnetophotonic crystals fabricated from a stack of four repetitions of layers of Bi-substituted yttrium iron garnet and SiO{sub 2} layers. The results of theoretical calculations in the framework of modified matrices approach are consistent with the obtained experimental data with the exception of the one cusp at 480 nm in the transverse Kerr effect spectra. Possible mechanisms of this disagreement are discussed.
CFT description of three-dimensional Kerr-de Sitter spacetime
International Nuclear Information System (INIS)
Fjelstad, Jens; Hwang, Stephen; Maansson, Teresia
2002-01-01
We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space
CFT description of three-dimensional Kerr-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Fjelstad, Jens E-mail: jens.fjelstad@kau.se; Hwang, Stephen E-mail: stephen.hwang@kau.se; Maansson, Teresia E-mail: teresia@physto.se
2002-10-07
We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space.
Scalar Dyon Production In Near Extremal Kerr-Newman Black Holes
Directory of Open Access Journals (Sweden)
Chen Chiang-Mei
2018-01-01
Full Text Available The pair production of charged scalar dyons is analytically studied in near-extremal Kerr-Newman (KN dyonic black holes. The pair production rate and its thermal interpretation are given. Moreover, the absorption cross section ratio has been compared with the two-point function of the conformal field theories (CFTs holographically dual to the near horizon geometry, namely warped AdS3, of the near extremal Kerr-Newman black holes to verify the threefold dyonic KN/CFTs correspondence.
Massive vector particles tunneling from Kerr and Kerr–Newman black holes
Directory of Open Access Journals (Sweden)
Xiang-Qian Li
2015-12-01
Full Text Available In this paper, we investigate the Hawking radiation of massive spin-1 particles from 4-dimensional Kerr and Kerr–Newman black holes. By applying the Hamilton–Jacobi ansatz and the WKB approximation to the field equations of the massive bosons in Kerr and Kerr–Newman space-time, the quantum tunneling method is successfully implemented. As a result, we obtain the tunneling rate of the emitted vector particles and recover the standard Hawking temperature of both the two black holes.
Josephson Metamaterial with a Widely Tunable Positive or Negative Kerr Constant
Zhang, Wenyuan; Huang, W.; Gershenson, M. E.; Bell, M. T.
2017-11-01
We report on the microwave characterization of a novel one-dimensional Josephson metamaterial composed of a chain of asymmetric superconducting quantum interference devices with nearest-neighbor coupling through common Josephson junctions. This metamaterial demonstrates a strong Kerr nonlinearity, with a Kerr constant tunable over a wide range, from positive to negative values, by a magnetic flux threading the superconducting quantum interference devices. The experimental results are in good agreement with the theory of nonlinear effects in Josephson chains. The metamaterial is very promising as an active medium for Josephson traveling-wave parametric amplifiers; its use facilitates phase matching in a four-wave-mixing process for efficient parametric gain.
Spatial Solitons and Induced Kerr Effects in Quasi-Phase-Matched Quadratic Media
DEFF Research Database (Denmark)
Clausen, Carl A. Balslev; Bang, Ole; Kivshar, Yu.S.
1997-01-01
We show that the evolution of the average intensity of cw beams in a quasi-phase-matched quadratic (or chi((2))) medium is strongly influenced by induced Kerr effects, such as self- and cross-phase modulation. We prove the existence of rapidly oscillating solitary waves (a spatial analog of the g......We show that the evolution of the average intensity of cw beams in a quasi-phase-matched quadratic (or chi((2))) medium is strongly influenced by induced Kerr effects, such as self- and cross-phase modulation. We prove the existence of rapidly oscillating solitary waves (a spatial analog...
Generating entangled states of continuous variables via cross-Kerr nonlinearity
Energy Technology Data Exchange (ETDEWEB)
Zhang Zhiming [Center for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Khosa, Ashfaq H [Center for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Ikram, Manzoor [Center for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Zubairy, M Suhail [Center for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)
2007-05-28
We propose a scheme for generating entanglement of quantum states with continuous variables (coherent states and squeezed vacuum states) of electromagnetical fields. The scheme involves cross-Kerr nonlinearity. It was shown that the cross-Kerr nonlinearity required for generating the superposition and entanglement of squeezed vacuum states is smaller than that required for coherent states. It was also found that the fidelity monotonously decreases with both the increase of the amplitude of the input coherent field and the increase of the deviation of the nonlinear phase shift from {pi}.
Energy extraction from a Konoplya–Zhidenko rotating non-Kerr black hole
Directory of Open Access Journals (Sweden)
Fen Long
2018-01-01
Full Text Available We have investigated the properties of the ergosphere and the energy extraction by Penrose process in a Konoplya–Zhidenko rotating non-Kerr black hole spacetime. We find that the ergosphere becomes thin and the maximum efficiency of energy extraction decreases as the deformation parameter increases. For the case with aM, we find that the maximum efficiency can reach so high that it is almost unlimited as the positive deformation parameter is close to zero, which is a new feature of energy extraction in such kind of rotating non-Kerr black hole spacetime.
Nearly deterministic quantum Fredkin gate based on weak cross-Kerr nonlinearity
Wu, Yun-xiang; Zhu, Chang-hua; Pei, Chang-xing
2016-09-01
A scheme of an optical quantum Fredkin gate is presented based on weak cross-Kerr nonlinearity. By an auxiliary coherent state with the cross-Kerr nonlinearity effect, photons can interact with each other indirectly, and a non-demolition measurement for photons can be implemented. Combined with the homodyne detection, classical feedforward, polarization beam splitters and Pauli-X operations, a controlled-path gate is constructed. Furthermore, a quantum Fredkin gate is built based on the controlled-path gate. The proposed Fredkin gate is simple in structure and feasible by current experimental technology.
Giant magneto-optical Kerr effect and universal Faraday effect in thin-film topological insulators.
Tse, Wang-Kong; MacDonald, A H
2010-07-30
Topological insulators can exhibit strong magneto-electric effects when their time-reversal symmetry is broken. In this Letter we consider the magneto-optical Kerr and Faraday effects of a topological insulator thin film weakly exchange coupled to a ferromagnet. We find that its Faraday rotation has a universal value at low frequencies θF=tan(-1)α, where α is the vacuum fine structure constant, and that it has a giant Kerr rotation θK=π/2. These properties follow from a delicate interplay between thin-film cavity confinement and the surface Hall conductivity of a topological insulator's helical quasiparticles.
Relativistic thick discs in the Kerr-de Sitter backgrounds
International Nuclear Information System (INIS)
Slany, Petr; StuchlIk, Zdenek
2005-01-01
Perfect fluid tori with a uniform distribution of the specific angular momentum, l(r, θ) = const, orbiting the Kerr-de Sitter black holes or naked singularities are studied. It is well known that the structure of equipotential surfaces of such marginally stable tori reflects the basic properties of any tori with a general distribution of the specific angular momentum. Closed equipotential surfaces corresponding to stationary thick discs are allowed only in the spacetimes admitting stable circular geodesics. The last closed surface crosses itself in the cusp(s) enabling the outflow of matter from the torus due to the violation of hydrostatic equilibrium. The inner cusp enables an accretion onto the central object. The influence of the repulsive cosmological constant, Λ > 0, on the equipotential surfaces lies in the existence of the outer cusp (with a stabilizing effect on the thick discs) and in the strong collimation of open equipotential surfaces along the rotational axis. Both the effects take place near a so-called static radius where the gravitational attraction is just balanced by the cosmic repulsion. The outer cusp enables excretion, i.e., the outflow of matter from the torus into the outer space. The plus-family discs (which are always co-rotating in the black-hole backgrounds but can be counter-rotating, even with negative energy of the fluid elements, in some naked-singularity backgrounds) are thicker and more extended than the minus-family ones (which are always counter-rotating in all backgrounds). For co-rotating discs in the naked-singularity spacetimes, the potential well between the centre of the disc and its edges at the cusps is usually much higher than in the black-hole spacetimes. If the parameters of naked-singularity spacetimes are very close to the parameters of extreme black-hole spacetimes, the family of possible disc-like configurations includes members with two isolated discs where the inner one is always a counter-rotating accretion
Michel Foucault et Paul Ricœur, vers un dialogue possible
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Simon Castonguay
2011-01-01
Full Text Available Il est désormais connu que Michel Foucault s’est intéressé à la fin de sa vie à l’ ”herméneutique du sujet.” Mais cette histoire de la constitution du sujet (ou de la subjectivité fait étrangement l’économie d’une réflexion sur le rôle de la compréhension, alors que Foucault qualifie son travail d’ ”ontologie historique de nous-mêmes.” C'est sur ce point précis qu’est ici mis à l'épreuve le caractère médiateur de l’œuvre de Paul Ricœur, dont l’herméneutique du soi prend en charge une ontologie de la compréhension. Suite à ces considérations, la seconde partie de l’article cherche à démontrer que la théorie de l’agir de Ricœur peut favoriser le passage d’une reconnaissance de type objectale à une reconnaissance des capacités du sujet à se tenir pour responsable. Ce passage sera opéré directement sur le modèle d’analyse du “dernier Foucault,” c’est-à-dire son concept-clé de “processus de subjectivation.”In his later work, Michel Foucault manifested a strong interest for the “hermeneutics of the subject.” Yet this history of the constitution of the subject (or subjectivity does without any reflection on the role of understanding, even though Foucault characterizes his project as a historical ontology of ourselves. The power of mediation emphasized in the work of Paul Ricœur may help us redefine an ontology of understanding through a hermeneutics of the self. Following this, the second part of the article aims to show that Ricœur’s theory of action can facilitate a transition from the recognition of the self, first described as “objectivation,” to a recognition of the subject’s capacity to be held responsible. This passage will draw on the model of analysis in the later Foucault, specifically, on his key concept of the subjectivation process.
Directory of Open Access Journals (Sweden)
Raffaele Federici
2017-08-01
Full Text Available In questa ricerca di senso fra la fine di un'epoca e la nuova visione del mondo, c’è, nei due Autori, quello che potrebbe chiamarsi una betweenness: Pareto, quasi un franco-italiano, e Michels, un italiano-tedesco, anzi un più che italiano. Nella linea di faglia rappresentata dal primo conflitto mondiale, i due sociologi sono in una doppia relazione interiore appunto franco-italiana Pareto e italo-tedesca Michels e una relazione esteriore fra il mondo di ieri e il mondo successivo al cataclisma che fu la prima guerra mondiale, quando ben quattro imperi colossali erano stati smembrati (l’Impero Russo, l’Impero Tedesco, l’Impero Austro-ungarico e l’Impero ottomano, nello stesso tempo in cui Emile Durkheim guardava con inquietudine alla disgregazione delle vecchie comunità tradizionali, dove il senso della crisi del tempo investe non solo le persone e i comportamenti, ma il mondo logico stesso. Lo scambio epistolare avviene nella stessa terra: Pareto a Celigny, sul lago di Ginevra , e Michels a Basilea , lungo le rive del Reno. Vi è, fra i due sociologi un profondo rispetto, che vedrà Robert Michels dedicare allo “scienziato e amico Vilfredo Pareto con venerazione” un’opera importante come “Problemi di sociologia applicata” pubblicata solo tre anni dopo il Trattato di Sociologia Generale del Maestro. In questa antologia di saggi Robert Michels, probabilmente composti fra il 1914 e il 1917, negli anni del grande cataclisma, anzi concepiti prima «dell’insediamento di questa terribile corte suprema di cassazione di tutte le nostre ideologie, che è la guerra» , quindi contemporanea al Trattato, il Maestro viene citato tre volte, come Max Weber, ma, de facto, la presenza di Pareto è continua. In particolare, il richiamo al Maestro è iscritto a due piste di ricerca: da una parte la realtà della ricerca sociologica e del suo amplissimo spettro di analisi e dall’altra la teoria della circolazione delle elités. È proprio
El “biopoder” en Michel Foucault. Emergencia y linaje de un concepto
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Verna Martínez Martín
2017-05-01
Full Text Available La losofía de Michel Foucault ha sido una de las influencias más importantes que el siglo XX ha ejercido sobre nuestro pensamiento político contemporáneo. Entre sus contribuciones, la noción de “biopoder” es notable tanto por el amplio espectro de problemas que ha señalado desde su creación por el pensador, cuanto por la flexibilidad con la que es capaz de cambiar su sentido en función del contexto de problematización en el que aparece. Para comprender cuál es el marco conceptual desde el que Foucault concibió esta noción en su Historia de la sexualidad, es necesario un trabajo de lectura atenta y análisis de las re exiones originales en torno a ella. Nuestra intención es prestar atención a cómo Foucault pensó el poder en sus cursos del Collège de France desde el inicio de la elabora- ción de Historia de la sexualidad.
Nacionalismos e internacionalismo: um debate entre Michael Löwy e Michel Cahen
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Ângela Lazagna
2008-11-01
Full Text Available Este artigo consiste em um debate realizado entre Michel Löwy e Michael Cahen em meados dos anos 1990 e revisto para esta publicação. Mesmo que a discussão refira-se a acontecimentos que até certo ponto podem ser considerados datados, a preocupação de fundo que é comum a esses artigos concede-lhes atualidade: a necessidade do aprofundamento de uma reflexão, a partir da teoria marxista, sobre o problema dos nacionalismos e do internacionalismo em tempos de mundialização. Esse aprofundamento, segundo os autores, faz-se necessário sobretudo por meio de uma reflexão que rompa criticamente com uma visão eurocêntrica dos diferentes nacionalismos e que supere a atitude de muitos marxistas de desprezarem tudo aquilo que não seja diretamente relevante à "consciência de classe".
Don Quixote, Sweded by Michel Gondry in Be Kind Rewind (2008
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Hogan Erin K.
2017-12-01
Full Text Available In the spirit of poetic license from Be Kind Rewind (2008, this article argues that Michel Gondry’s film “swedes,” its playful neologism for ersatz remaking of Hollywood and classic films, Miguel de Cervantes’s Don Quixote. The feature follows the Sanchification of Jerry (Jack Black, Gondry’s Don Quixote, and Quixotification of Mike (Mos Def, Gondry’s Sancho, as they nostalgically wrong cinematic rights through sweding and try to save their working-class neighbourhood from condemnation and gentrification through community film making. Gondry swedes the Quixote through his engagement with major themes and operations in Cervantes’s classic, including nostalgia, story-telling, conflicts between reality and fantasy, authorship, the grotesque and carnivalesque, (anti-heroes, race and gender-bending, genre, and addressees turned addressers. This article discusses Be Kind Rewind’s relationship to Hollywoodian and Cervantine classics through the theoretical frameworks of Julio Garcia Espinosa’s imperfect cinema and Foucauldian semiotics, respectively. Be Kind Rewind uses and abuses Hollywood stereotypes to re-purpose them for a critique of discriminatory practices. Where casting is concerned and where Michel’s characters diverge from Miguel’s, Be Kind Rewind advances that skin colour is not an arbitrary sign and that race has historical and contemporary meaning in intercultural interactions.
Villa San Michele at Capri – a House with a distinct home for "Genius Loci"
DEFF Research Database (Denmark)
Fisker, Anna Marie; Danielsen, Mads Harder
2012-01-01
on the spot. When we approached Capri by crossing the Neapolitan bay the first thing our eyes saw was the chapel of San Michele resting high above the blue waters at the top of the steep cliffs - on the edge of the abyss. This place is also the location of the Egyptian Sphinx, half lion, half woman...... that the spirit of the place adjoins a metaphysical core of architecture; and as the very core of architecture could be connected to an absolute truth so it seems that genius loci is related to truth; even though it is a truth that is not directly visible. We ask in this paper if it is a truth that is perennially...... are going to hear the Sphinx ask us questions, all these riddling puzzles, we first have to ask the Sphinx to know how to ask questions. That genius loci are present in architectural theory owes much to the Scandinavian theoretician and architect Christian Norberg-Schulz, who emphasized considerations...
La Filosofía de Michel Serres: una Moral de Base Objetiva
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Antonio Arellano Hernández
2000-01-01
Full Text Available Los temas que preocupan al filósofo francés Michel Serres son variados y, en cierto sentido, caóticos. Sin embargo, uno de los puntos esenciales de la filosofía del autor tiene como base empírica el problema de la moral, que el hombre deposita en los objetos tecnológicos en su proceso de elaboración. No es exagerado decir que el único propósito de su filosofía es el tema de la relación entre la ética y el desarrollo científico, que se manifestó con el uso de las bombas atómicas contra indefensos ciudadanos japoneses en la Segunda Guerra Mundial. El abordaje del tema de reflexión será el resultado de un camino explicativo que comienza por presentar la formación y el contexto de la obra del autor, continúa con la exposición de su método de trabajo y las nociones que integran el núcleo de su pensamiento. Al avanzar en esta propedéutica se analizarán sus nociones sobre la invención del futuro, el papel que en ella juega la tecnociencia y la necesidad de dotarla de una base moral.
The production of the psychiatric subject: power, knowledge and Michel Foucault.
Roberts, Marc
2005-01-01
The issue of power has become increasingly important within psychiatry, psychotherapy and mental health nursing generally. This paper will suggest that the work of Michel Foucault, the French philosopher and historian, has much to contribute to the discussion about the nature, existence and exercise of power within contemporary mental health care. As well as examining his original and challenging account of power, Foucault's emphasis on the intimate relationship between power and knowledge will be explored within the context of psychiatry and mental health nursing. This is to say that the paper will investigate Foucault's account of how power and knowledge are central to the process by which human beings are 'made subjects' and therefore how 'psychiatric identities' are produced. In doing so, it will be suggested that Foucault's work can not only make a valuable contribution to contemporary discussions about power and knowledge, but can also provide a significant critique and reconceptualization of the theoretical foundations and associated diagnostic and therapeutic practices of psychiatry and mental health nursing.
Georges Bataille, Michel Leiris e a experiência do sagrado no entreguerras
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Júlia Vilaça Goyatá
2014-12-01
Full Text Available O presente artigo tem como objetivo elucidar os usos e sentidos da noção de sagrado nas formulações teóricas e nas trajetórias intelectuais de Georges Bataille (1897-1962 e Michel Leiris (1901-1990 na Paris dos anos 1930. Em meio às diversas experiências estético-políticas da época, que questionavam as possíveis formas da ação política tendo em vista sua ligação com a arte, destaca-se a proposta do Collège de Sociologie (1937-1939, associação animada pelos autores junto a Roger Caillois (1913-1978. O grupo toma o sagrado em dupla articulação: ao mesmo tempo que conceito descritivo, ele passa a ser entendido também como um operador político. Tal ideia é o ponto de partida para as reflexões conjugadas e ao mesmo tempo originais de Bataille e Leiris.
Highlights from e-EPS: Jean-Michel Raimond wins EPS Edison-Volta Prize 2014
Martina Knoop, e-EPS News
2014-01-01
e-EPS News is a monthly addition to the CERN Bulletin line-up, showcasing articles from e-EPS – the European Physical Society newsletter – as part of a collaboration between the two publications. The European Physical Society has the pleasure to announce that the 2014 EPS Edison-Volta Prize is awarded to Jean-Michel Raimond for “seminal contribution to physics (that) have paved the way for novel explorations of quantum mechanics and have opened new routes in quantum information processing”. J.-M. Raimond’s PhD thesis was supervised by Serge Haroche at the École Normale Supérieure in Paris, France, in the early 1980′s, and together S. Haroche, M. Brune and J.-M. Raimond have built an extremely successful research group since then. J.-M. Raimond has made seminal contributions to the development of cavity QED experiments, in particular involving circular Rydberg atoms interacting with very high-Q superc...
Critical thinking and contemporary mental health care: Michel Foucault's "history of the present".
Roberts, Marc
2017-04-01
In order to be able to provide informed, effective and responsive mental health care and to do so in an evidence-based, collaborative and recovery-focused way with those who use mental health services, there is a recognition of the need for mental health professionals to possess sophisticated critical thinking capabilities. This article will therefore propose that such capabilities can be productively situated within the context of the work of the French philosopher Michel Foucault, one of the most challenging, innovative and influential thinkers of the 20th century. However, rather than focusing exclusively upon the content of Foucault's work, it will be suggested that it is possible to discern a general methodological approach across that work, a methodological approach that he refers to as "the history of the present." In doing so, Foucault's history of the present can be understood as a productive, albeit provisional, framework in which to orientate the purpose and process of critical thinking for mental health professionals by emphasizing the need to both historicize and politicize the theoretical perspectives and therapeutic practices that characterize contemporary mental health care. © 2016 John Wiley & Sons Ltd.
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Wening Udasmoro
2018-02-01
Full Text Available In literature, questions of the self and the other are frequently presented. The identity politics that gained prominence after the attack on the World Trade Center in New York on 11 September 2001 has occupied considerable space in this debate throughout the globe, including in France. One example of a novel dealing with the self and other is Michel Houellebecq’s Soumission (2015. This article attempts to explore the processes of selfing and othering in this work. The politics of identity that seems to present Muslims and Islam as the other and French as the self is also extended to other identities and aspects involved in the novel. This article attempts to show, first, how the French author Houellebecq positions the self and other in Soumission; second, the type of self and other the novel focuses on; and third, how its selfing and othering processes reveal the gender hierarchy and social categorization of French society. It finds that the novel presents a hierarchy in its narrative through which characters are positioned based on their gender and sexual orientation, as well as their age and ethnic heritage.
Bodies spoken by the other: A reading of Michel de Certeau
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Geraldo Luiz De Mori
2016-12-01
Full Text Available This article aims to schematize a reflection of Michel de Certeau regarding the various meanings attributed to the body by Ocidental culture, pointing out the resignifications of these meanings by the Christian religion. For this, in methodological terms, attention was given to interdisciplinary dialogue furthered by this author who easily moved among the fields of psychoanalysis, history, linguistics, philosophy, theology, and spirituality. As a first hypothesis, it postulated that for De Certeau the body is configured as a viable fiction of social practices, that is, an instance of authority capable of provoking agreements, conflicts and transformations. This is because, according to the aforementioned Jesuit, the body is constituted simultaneously both as a symbolic contribution to institutional powers as well as a mediation for political and cultural bricolage, departures and transgressions advanced in daily life. Concomitantly, it is considered, as a second hypothesis that, as indicated by De Certeau, the body in the Christian tradition was lived as a mystic instance, that is, as enunciating, by its manifestations, the desire to be habited by the other/Other. It is then suggested that an actualization of this existential and political condition now enables subjects to turn positive their intrinsic incompleteness and fragile humanness, favoring, as a result, historical and social experiences shared and felt.
Intrinsic and Extrinsic Origins of the Polar Kerr Effect in a Chiral p-WAVE Superconductor
Goryo, Jun
Recently, the measurement of the polar Kerr effect (PKE) in the quasi two-dimensional superconductor Sr2RuO4, which is motivated to observe the chirality of px + ipy-wave pairing, has been reported. We clarify that the PKE has intrinsic and extrinsic (disorder-induced) origins. The extrinsic contribution would be dominant in the PKE experiment.
On the instability regime of the rotating Kerr spacetime to massive scalar perturbations
International Nuclear Information System (INIS)
Hod, Shahar
2012-01-01
The instability of rotating Kerr black holes due to massive scalar perturbations is investigated. It is well known that a bosonic field impinging on a Kerr black hole can be amplified as it scatters off the hole. This superradiant scattering occurs for frequencies in the range ω< mΩ, where Ω is the angular frequency of the black hole and m is the azimuthal harmonic index of the mode. If the incident field has a non-zero rest mass, μ, then the mass term effectively works as a mirror, reflecting the scattered wave back towards the black hole. The wave may bounce back and forth between the black hole and some turning point amplifying itself each time. This may lead to a dynamical instability of the system, a phenomena known as a “black-hole bomb”. In this work we provide a bound on the instability regime of rotating Kerr spacetimes. In particular, we show that Kerr black holes are stable to massive perturbations in the regime μ⩾√(2)mΩ.
Extended Kerr-Schild spacetimes: general properties and some explicit examples
Czech Academy of Sciences Publication Activity Database
Málek, Tomáš
2014-01-01
Roč. 31, č. 18 (2014), s. 185013 ISSN 0264-9381 R&D Projects: GA ČR GB14-37086G Institutional support: RVO:67985840 Keywords : Kerr-Schild spacetimes * algebraic classification * higher dimensions Subject RIV: BA - General Mathematics Impact factor: 3.168, year: 2014 http://iopscience.iop.org/0264-9381/31/18/185013/
Fermion bound states in the Kerr-Newman field with magnetic charge
International Nuclear Information System (INIS)
Gal'tsov, D.V.; Ershov, A.A.
1987-01-01
Approximate solutions of Dirac equations for 1/2 spin charged particles in the Kerr-Newman field are constructed. An equation for quasistationary states energy, taking account of their possible decay due to tunnelling in the black hole, is obtained. A problem of existence of zero modes is discussed
On the energy emission by a Kerr black hole in the superradiant range
International Nuclear Information System (INIS)
Curir, A.
1985-01-01
A new redefined ''Unruh vacuum'' has been used in order to obtain the thermal Hawkin emission in a Kerr geometry in the superradiant range. It is also shown that a new type of vacuum is needed to obtain the global emission from a rotating black hole in the superradiant range. The formula describing such global emission is given. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Wang, Xiao, E-mail: sps_wangx@ujn.edu.cn [School of Physics and Technology, University of Jinan, Jinan 250022 (China); School of Material Science and Engineering, University of Jinan, Jinan 250022 (China); Lian, Jie [School of Information Science and Engineering, Shandong University, Jinan 250100 (China); Li, Ping; Xu, XiJin [School of Physics and Technology, University of Jinan, Jinan 250022 (China); Li, MengMeng [School of Information Science and Engineering, Shandong University, Jinan 250100 (China)
2017-01-15
The Fresnel equations are solved to analyze the reflection and propagation properties of the ordinary and extraordinary light of the optically anisotropic magnetic film. Using the boundary and propagation matrix, the longitudinal magneto-optical Kerr rotation expression is derived. After that, simulations are performed on optically anisotropic and isotropic Co/SiO{sub 2} film. Results show that for Co material in the thin-film limit, the anisotropic Co can provide larger max rotations than the isotropic Co in the visible region. This is because that the refractive index discrepancy of optically anisotropic Co film reduces the Fresnel reflective coefficient r{sub pp,} which improves the Kerr rotation. This makes the optically anisotropic Co film more effective in magneto optical sensor design and device fabrication. - Highlights: • In this work, using the boundary matrix and media propagation matrix developed by Zak and S.D.Bader,we get the analytical solution of the magneto-optical Kerr rotation of the optical anisotropic magnetic film. • Results show that for film in the thin-film limit, the anisotropic Co can provide larger maximum rotations than the isotropic Co. • The improvement of Kerr rotation can be attributed to the refractive index discrepancy of optically anisotropic Co film which reduce the Fresnel reflective coefficient rpp.
Pump induced normal mode splittings in phase conjugation in a Kerr ...
Indian Academy of Sciences (India)
Abstract. Phase conjugation in a Kerr nonlinear waveguide is studied with counter-propagating normally incident pumps and a probe beam at an arbitrary angle of incidence. Detailed numerical results for the specular and phase conjugated reflectivities are obtained with full account of pump depletion. For sufficient ...
A test particle motion in the Kerr field with fluctuating perturbations
International Nuclear Information System (INIS)
Zhuk, I.T.; Piragas, K.A.
1982-01-01
Motion of a stochastic test particle in the Kerr black hole field in the approximation of Brown interaction is considered. Probability distribution of orbit position by the latitude angle is revealed, bifurcation values of their parameters are determined. Fluctuating instability of orbits characteristic of critical modes of motion is investigated, properties of some statistical characteristics of the system are identified
International Nuclear Information System (INIS)
Pack, M. V.; Camacho, R. M.; Howell, J. C.
2006-01-01
We present a theory describing the transients and rise times of the refractive Kerr nonlinearity which is enhanced using electromagnetically induced transparency (EIT). We restrict our analysis to the case of a pulsed signal field with continuous-wave EIT fields, and all fields are well below saturation. These restrictions enable the reduction of an EIT Kerr, four-level, density-matrix equation to a two-level Bloch-vector equation which has a simple and physically intuitive algebraic solution. The physically intuitive picture of a two-level Bloch vector provides insights that are easily generalized to more complex and experimentally realistic models. We consider generalization to the cases of Doppler broadening, many-level EIT systems (we consider the D1 line of 87 Rb), and optically thick media. For the case of optically thick media we find that the rise time of the refractive EIT Kerr effect is proportional to the optical thickness. The rise time of the refractive EIT Kerr effect sets important limitations for potential few-photon applications
Complete description of photon trajectories in the Kerr-Newman space-time
Energy Technology Data Exchange (ETDEWEB)
Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; Turolla, R [International School for Advanced Studies, Trieste (Italy)
1981-08-01
The complete description of null trajectories in the Kerr-Newman space-time is given in terms of the parameters of the source and of the constants of motion. The conditions for orbital and vortical motion are studied in detail and the locus of turning points is given for any choice of the parameters.
Clark Kerr's Multiversity and Technology Transfer in the Modern American Research University
Sigurdson, Kristjan T.
2013-01-01
In the early 1960s, Clark Kerr, the famed American educationalist and architect of the California public higher education system, took up the task of describing the emergent model of the contemporary American university. Multiversities, as he called them, were the large powerful American universities that packaged the provision of undergraduate,…
An Integral Spectral Representation of the Propagator for the Wave Equation in the Kerr Geometry
Finster, F.; Kamran, N.; Smoller, J.; Yau, S.-T.
2005-12-01
We consider the scalar wave equation in the Kerr geometry for Cauchy data which is smooth and compactly supported outside the event horizon. We derive an integral representation which expresses the solution as a superposition of solutions of the radial and angular ODEs which arise in the separation of variables. In particular, we prove completeness of the solutions of the separated ODEs.
Generating multiphoton Greenberger-Horne-Zeilinger states with weak cross-Kerr nonlinearity
International Nuclear Information System (INIS)
Jin, Guang-Sheng; Lin, Yuan; Wu, Biao
2007-01-01
We propose a scheme to generate polarization-entangled multiphoton Greenberger-Horne-Zeilinger states with weak cross-Kerr nonlinearity based on controlled bus rotation and subsequent homodyne measurement. Our method is simple in operation and has high success probabilities with near perfect fidelities in an ideal case
Kerr-like behaviour of second harmonic generation in the far-off resonant regime
Peřinová, Vlasta; Lukš, Antonín; Křepelka, Jaromír; Leoński, Wiesław; Peřina, Jan
2018-05-01
We separate the Kerr-like behaviour of the second-harmonic generation in the far-off resonant regime from the oscillations caused by the time-dependence of the interaction energy. To this purpose, we consider the approximation obtained from the exact dynamics by the method of small rotations. The Floquet-type decomposition of the approximate dynamics comprises the Kerr-like dynamics and oscillations of the same order of magnitude as those assumed for the exact dynamics of the second-harmonic generation. We have found that a superposition of two states of concentrated quantum phase arises in the fundamental mode in the second-harmonic generation in the far-off resonant limit at a later time than a superposition of two coherent states in the corresponding Kerr medium and the difference is larger for higher initial coherent amplitudes. The quantum phase fluctuation is higher for the same initial coherent amplitudes in the fundamental mode in the second-harmonic generation in the far-off resonant limit than in the corresponding Kerr medium and the difference is larger for higher initial coherent amplitudes.
Theory of Kerr and Faraday rotations and linear dichroism in Topological Weyl Semimetals.
Kargarian, Mehdi; Randeria, Mohit; Trivedi, Nandini
2015-08-03
We consider the electromagnetic response of a topological Weyl semimetal (TWS) with a pair of Weyl nodes in the bulk and corresponding Fermi arcs in the surface Brillouin zone. We compute the frequency-dependent complex conductivities σαβ(ω) and also take into account the modification of Maxwell equations by the topological θ-term to obtain the Kerr and Faraday rotations in a variety of geometries. For TWS films thinner than the wavelength, the Kerr and Faraday rotations, determined by the separation between Weyl nodes, are significantly larger than in topological insulators. In thicker films, the Kerr and Faraday angles can be enhanced by choice of film thickness and substrate refractive index. We show that, for radiation incident on a surface with Fermi arcs, there is no Kerr or Faraday rotation but the electric field develops a longitudinal component inside the TWS, and there is linear dichroism signal. Our results have implications for probing the TWS phase in various experimental systems.
Life as the Middle Child: A Conversation With Mary Margaret Kerr
Teagarden, James M.; Zabel, Robert H.; Kaff, Marilyn S.
2015-01-01
As part of an ongoing oral history project, a conversation was held with Dr. Mary Margaret Kerr on the past, present, and possible future of the field of providing services to children with emotional-behavioral disorders. Dr. Wood stresses the increasing importance of providing an interdisciplinary approach to meet the needs for children or, as…
International Nuclear Information System (INIS)
Zheltikov, Aleksei M; Koroteev, Nikolai I; Naumov, A N; Fedotov, Andrei B; Magnitskiy, Sergey A; Sidorov-Biryukov, D A
1998-01-01
An investigation was made of the characteristics of the optical Kerr effect in a spiropyran solution. It was found that this effect makes it possible to distinguish the coloured and uncoloured forms of spiropyran and that it represents a promising method for nondestructive data reading in three-dimensional optical memory systems based on photochromic materials. (letters to the editor)
Directory of Open Access Journals (Sweden)
Giorgio Baruchello
2014-03-01
Full Text Available Review of: Michele Renee Salzman, Marvina A. Sweeney & William Adler (eds., The Cambridge History of Religions in the Ancient World (2 vols. (New York: Cambridge University Press, 2013
Self-force correction to geodetic spin precession in Kerr spacetime
Akcay, Sarp
2017-08-01
We present an expression for the gravitational self-force correction to the geodetic spin precession of a spinning compact object with small, but non-negligible mass in a bound, equatorial orbit around a Kerr black hole. We consider only conservative backreaction effects due to the mass of the compact object (m1), thus neglecting the effects of its spin s1 on its motion; i.e., we impose s1≪G m12/c and m1≪m2, where m2 is the mass parameter of the background Kerr spacetime. We encapsulate the correction to the spin precession in ψ , the ratio of the accumulated spin-precession angle to the total azimuthal angle over one radial orbit in the equatorial plane. Our formulation considers the gauge-invariant O (m1) part of the correction to ψ , denoted by Δ ψ , and is a generalization of the results of Akcay et al. [Classical Quantum Gravity 34, 084001 (2017), 10.1088/1361-6382/aa61d6] to Kerr spacetime. Additionally, we compute the zero-eccentricity limit of Δ ψ and show that this quantity differs from the circular orbit Δ ψcirc by a gauge-invariant quantity containing the gravitational self-force correction to general relativistic periapsis advance in Kerr spacetime. Our result for Δ ψ is expressed in a manner that readily accommodates numerical/analytical self-force computations, e.g., in the radiation gauge, and paves the way for the computation of a new eccentric-orbit Kerr gauge invariant beyond the generalized redshift.
Kerr-effect analysis in a three-level negative index material under magneto cross-coupling
Boutabba, N.
2018-02-01
We discuss the feasibility of the Kerr effect in negative refractive index materials under magneto cross-coupling and reservoir interaction. The considered medium is a typical three-level atomic system where we derive both the refractive and the gain spectrum. The profiles are analyzed for a weak probe field, and for varying strengths of the strong control field. The considered scheme shows an enhancement of the Kerr nonlinearity which we attribute to the contribution of the electromagnetic components of the fields. For more realistic experimental conditions, we discuss the dependence of the Kerr effect on different thermal bath coupling constants.
International Nuclear Information System (INIS)
Bhadra, Jhumpa; Debnath, Ujjal
2012-01-01
In this work, we have studied accretion of the dark energies in new variable modified Chaplygin gas (NVMCG) and generalized cosmic Chaplygin gas (GCCG) models onto Schwarzschild and Kerr-Newman black holes. We find the expression of the critical four velocity component which gradually decreases for the fluid flow towards the Schwarzschild as well as the Kerr-Newman black hole. We also find the expression for the change of mass of the black hole in both cases. For the Kerr-Newman black hole, which is rotating and charged, we calculate the specific angular momentum and total angular momentum. We showed that in both cases, due to accretion of dark energy, the mass of the black hole increases and angular momentum increases in the case of a Kerr-Newman black hole. (orig.)
Induced Kerr effects and self-guided beams in quasi-phase-matched quadratic media [CBC4
DEFF Research Database (Denmark)
Clausen, Carl A. Balslev; Bang, Ole; Kivshar, Yuri S.
1997-01-01
We show that quasi-phase-matching of quadratic media induces Kerr effects, such as self- and cross-phase modulation, and leads to the existence of a novel class of solitary waves, QPM-solitons......We show that quasi-phase-matching of quadratic media induces Kerr effects, such as self- and cross-phase modulation, and leads to the existence of a novel class of solitary waves, QPM-solitons...
Repensando o conceito de diglossia à luz de Michel de Certeau
Directory of Open Access Journals (Sweden)
Miguel Afonso Linhares
2016-03-01
Full Text Available O presente trabalho consiste em uma reflexão sobre o conceito de diglossia, uma palavra cuja especialização semântica nos estudos linguísticos se deu através de Jean Psichari em 1885. Não obstante, veio ganhar precisão teórica apenas em 1959, por Charles Ferguson. A partir da publicação do seu artigo, o conceito teve um sucesso imediato na Sociolinguística. Este artigo segue a esteira dessas discussões, com o objetivo de repensar o sujeito falante da “variedade baixa” ou “língua dominada”. Para tanto, valemo-nos da reflexão de Michel de Certeau (1994 sobre o cotidiano, especialmente das categorias de estratégia e de tática. Na primeira seção do artigo, traçamos um percurso pela história do termo diglossia, desde os seus significados nos primeiros testemunhos até a sua consolidação como conceito científico através de Ferguson (1959 e Fishman (1967. A seguinte é um encaminhamento à reflexão: expomos uma leitura crítica dos artigos mencionados e algumas críticas por parte de outros sociolinguistas. A terceira é o lugar de dar algumas informações sobre o caso de diglossia que serve de fundamento e ilustração à reflexão: a diglossia espanhol-catalão na Catalunha. Enfim, na quarta o leitor alcança a reflexão almejada: o sujeito falante da “variedade baixa” ou “língua dominada” não é um mero paciente em uma relação alto-baixo ou dominante-dominado, mas também um agente no campo hegemônico, que usa de táticas para contra-arrestar a dominação.
Reformulación del cuestionario de Michel para tamizaje de migraña
Directory of Open Access Journals (Sweden)
Luis Alfonso Díaz Martínez
2006-10-01
Full Text Available Antecedentes. Al estimar la prevalencia de migraña es importante conocer la capacidad discriminativa de la prueba empleada. El cuestionario de diagnóstico estandarizado para migraña de Michel es una herramienta útil en este sentido, pero es posible mejorar su capacidad diagnóstica ajustando los puntos asignados a cada ítem evaluado. Material y métodos. Se aplicó el cuestionario a 170 estudiantes de psicología seleccionados al azar, con posterior evaluación por neurólogo para corroborar el diagnóstico de migraña. Se utilizó la metodología de Kraemer para reasignar el puntaje del cuestionario con base a la asociación de un modelo saturado de regresión binomial de los ítems del cuestionario. Se estimaron las curvas receptor-operador (ROC para el sistema de puntuación original y para el sistema hallado, comparándolos por el método de máxima verosimilitud. Resultados: Con los puntajes originales el área bajo ROC fue de 0.8529; el mejor puntaje discriminatorio 13 puntos, con sensibilidad de 58.6 por ciento (IC95% 44.9%-71.4%, especificidad 89.3 por ciento (IC 95% 82.0%-94.3% y concordancia de 78.8 por ciento (IC 95% 71.9%-84.7%. Con el nuevo puntaje el área bajo ROC pasó a 0.907; la mejor capacidad de discriminación está en 18 puntos, con sensibilidad de 65.5 por ciento (IC95% 51.9%-77.5%, especificidad de 92.0 por ciento (IC95% 85.3%-93.3% y concordancia de 84.7 por ciento (IC95% 76.4%-89.3%. La ROC del nuevo sistema de puntuación es mejor que la original (p=0.016. Conclusiones. La reformulación del cuestionario optimiza la capacidad discriminatoria del cuestionario.
Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Wang, Mingzhi; Chen, Songbai; Jing, Jiliang, E-mail: wmz9085@126.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)
2017-10-01
We have investigated the shadow of a Konoplya-Zhidenko rotating non-Kerr black hole with an extra deformation parameter. The spacetime structure arising from the deformed parameter affects sharply the black hole shadow. With the increase of the deformation parameter, the size of the shadow of black hole increase and its shape becomes more rounded for arbitrary rotation parameter. The D-shape shadow of black hole emerges only in the case a <2√3/3\\, M with the proper deformation parameter. Especially, the black hole shadow possesses a cusp shape with small eye lashes in the cases with a >M, and the shadow becomes less cuspidal with the increase of the deformation parameter. Our result show that the presence of the deformation parameter yields a series of significant patterns for the shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole.
Kerr-Taub-NUT General Frame, Energy, and Momentum in Teleparallel Equivalent of General Relativity
Directory of Open Access Journals (Sweden)
Gamal G. L. Nashed
2012-01-01
Full Text Available A new exact solution describing a general stationary and axisymmetric object of the gravitational field in the framework of teleparallel equivalent of general relativity (TEGR is derived. The solution is characterized by three parameters “the gravitational mass M, the rotation a, and the NUT L.” The vierbein field is axially symmetric, and the associated metric gives the Kerr-Taub-NUT spacetime. Calculation of the total energy using two different methods, the gravitational energy momentum and the Riemannian connection 1-form Γα̃β, is carried out. It is shown that the two methods give the same results of energy and momentum. The value of energy is shown to depend on the mass M and the NUT parameter L. If L is vanishing, then the total energy reduced to the energy of Kerr black hole.
Modified dynamic Stark shift and depopulation rate of an atom inside a Kerr nonlinear blackbody
International Nuclear Information System (INIS)
Yin Miao; Cheng Ze
2009-01-01
We investigate the dynamic Stark shift and atomic depopulation rate induced by real photons in a Kerr nonlinear blackbody. We found that the dynamic Stark shift and atomic depopulation rate are equally modified by a nonlinear contribution factor and a linear contribution factor under a transition temperature T c . The nonlinear contribution factor depends on the Kerr nonlinear coefficient as well as the absolute temperature. Below T c , the absolute values of the dynamic Stark shift and depopulation rate of a single atomic state (not the ground state) are correspondingly larger than those in a normal blackbody whose interior is filled with a nonabsorbing linear medium. Above T c , the dynamic Stark shift and atomic depopulation rate are correspondingly equal to those in a normal blackbody with a nonabsorbing linear medium in its interior.
Global embedding of the Kerr black hole event horizon into hyperbolic 3-space
International Nuclear Information System (INIS)
Gibbons, G. W.; Herdeiro, C. A. R.; Rebelo, C.
2009-01-01
An explicit global and unique isometric embedding into hyperbolic 3-space, H 3 , of an axi-symmetric 2-surface with Gaussian curvature bounded below is given. In particular, this allows the embedding into H 3 of surfaces of revolution having negative, but finite, Gaussian curvature at smooth fixed points of the U(1) isometry. As an example, we exhibit the global embedding of the Kerr-Newman event horizon into H 3 , for arbitrary values of the angular momentum. For this example, considering a quotient of H 3 by the Picard group, we show that the hyperbolic embedding fits in a fundamental domain of the group up to a slightly larger value of the angular momentum than the limit for which a global embedding into Euclidean 3-space is possible. An embedding of the double-Kerr event horizon is also presented, as an example of an embedding that cannot be made global.
An observational criterion to look for an inspiral in a non-Kerr spacetime
International Nuclear Information System (INIS)
Apostolatos, Theocharis A; Lukes-Gerakopoulos, Georgios; Deligiannis, John; Contopoulos, George
2009-01-01
In this short article we present a useful observational tool for gravitational wave detectors. More specifically, if we are looking for extreme-mass-ratio inspiraling objects in a non-Kerr spacetime, we could exploit the consequences of the KAM and the Poincare-Birkhoff theorem which predicts plateaus in the ratio of frequencies f ρ /f z , that are related to a generic geodesic orbit in such a spacetime, as a function of the initial conditions of the orbit itself. While both these frequencies are changing under radiation reaction, their ratio is expected to stay stationary if it passes through such a plateau. Therefore, if detectors are able to discern the fundamental frequencies due to ρ and z oscillations of the orbit, they could in principle detect the non-Kerr-ness of the spacetime involved, just by monitoring the ratio of these two frequencies.
International Nuclear Information System (INIS)
Bini, Donato; Geralico, Andrea; Luongo, Orlando; Quevedo, Hernando
2009-01-01
An exact solution of Einstein's field equations in empty space first found in 1985 by Quevedo and Mashhoon is analyzed in detail. This solution generalizes Kerr spacetime to include the case of matter with an arbitrary mass quadrupole moment and is specified by three parameters, the mass M, the angular momentum per unit mass a and the quadrupole parameter q. It reduces to the Kerr spacetime in the limiting case q = 0 and to the Erez-Rosen spacetime when the specific angular momentum a vanishes. The geometrical properties of such a solution are investigated. Causality violations, directional singularities and repulsive effects occur in the region close to the source. Geodesic motion and accelerated motion are studied on the equatorial plane which, due to the reflection symmetry property of the solution, also turns out to be a geodesic plane.
Diode-pumped Kerr-lens mode-locked femtosecond Yb:YAG ceramic laser
Zi-Ye, Gao; Jiang-Feng, Zhu; Ke, Wang; Jun-Li, Wang; Zhao-Hua, Wang; Zhi-Yi, Wei
2016-02-01
We experimentally demonstrated a diode-pumped Kerr-lens mode-locked femtosecond laser based on an Yb:YAG ceramic. Stable laser pulses with 97-fs duration, 2.8-nJ pulse energy, and 320-mW average power were obtained. The femtosecond oscillator operated at a central wavelength of 1049 nm and a repetition rate of 115 MHz. To the best of our knowledge, this is the first demonstration of a Kerr-lens mode-locked operation in a diode-pumped Yb:YAG ceramic laser with sub-100 fs pulse duration. Project supported by the National Major Scientific Instrument Development Project of China (Grant No. 2012YQ120047), the National Natural Science Foundation of China (Grant No. 61205130), and the Fundamental Research Funds for the Central Universities, China (Grant No. JB140502).
Homoclinic orbits around spinning black holes. I. Exact solution for the Kerr separatrix
International Nuclear Information System (INIS)
Levin, Janna; Perez-Giz, Gabe
2009-01-01
For equatorial Kerr orbits, we show that each separatrix between bound and plunging geodesics is a homoclinic orbit--an orbit that asymptotes to an energetically-bound, unstable circular orbit. We derive exact expressions for these trajectories in terms of elementary functions. We also clarify the formal connection between the separatrix and zoom-whirl orbits and show that, contrary to popular belief, zoom-whirl behavior is not intrinsically a near-separatrix phenomenon. This paper focuses on homoclinic behavior in physical space, while in a companion paper we paint the complementary phase space portrait. Although they refer to geodesic motion, the exact solutions for the Kerr separatrix could be useful for analytic or numerical studies of eccentric transitions from orbital to plunging motion under the dissipative effects of gravitational radiation.
Stable one-dimensional periodic waves in Kerr-type saturable and quadratic nonlinear media
International Nuclear Information System (INIS)
Kartashov, Yaroslav V; Egorov, Alexey A; Vysloukh, Victor A; Torner, Lluis
2004-01-01
We review the latest progress and properties of the families of bright and dark one-dimensional periodic waves propagating in saturable Kerr-type and quadratic nonlinear media. We show how saturation of the nonlinear response results in the appearance of stability (instability) bands in a focusing (defocusing) medium, which is in sharp contrast with the properties of periodic waves in Kerr media. One of the key results discovered is the stabilization of multicolour periodic waves in quadratic media. In particular, dark-type waves are shown to be metastable, while bright-type waves are completely stable in a broad range of energy flows and material parameters. This yields the first known example of completely stable periodic wave patterns propagating in conservative uniform media supporting bright solitons. Such results open the way to the experimental observation of the corresponding self-sustained periodic wave patterns
The effect of damping on a quantum system containing a Kerr-like medium
Mohamed, A.-B. A.; Sebawe Abdalla, M.; Obada, A.-S. F.
2018-05-01
An analytical description is given for a model which represents the interaction between Su(1,1) and Su(2) quantum systems taking into account Su(1,1)-cavity damping and Kerr medium properties. The analytic solution for the master equation of the density matrix is obtained. The examination of the effects of the damping parameter as well as the Kerr-like medium features is performed. The atomic inversion is discussed where the revivals and collapses phenomenon is realized at the considered period of time. Our study is extended to include the degree of entanglement where the system shows partial entanglement in all cases, however, disentanglement is also observed. The death and rebirth is seen in the system provided one selects the suitable values of the parameters. The correlation function of the system shows non-classical as well as classical behavior.
Principal Killing strings in higher-dimensional Kerr-NUT-(A)dS spacetimes
Boos, Jens; Frolov, Valeri P.
2018-04-01
We construct special solutions of the Nambu-Goto equations for stationary strings in a general Kerr-NUT-(A)dS spacetime in any number of dimensions. This construction is based on the existence of explicit and hidden symmetries generated by the principal tensor which exists for these metrics. The characteristic property of these string configurations, which we call "principal Killing strings," is that they are stretched out from "infinity" to the horizon of the Kerr-NUT-(A)dS black hole and remain regular at the latter. We also demonstrate that principal Killing strings extract angular momentum from higher-dimensional rotating black holes and interpret this as the action of an asymptotic torque.
Optical Kerr effect in graphene: Theoretical analysis of the optical heterodyne detection technique
Savostianova, N. A.; Mikhailov, S. A.
2018-04-01
Graphene is an atomically thin two-dimensional material demonstrating strong optical nonlinearities, including harmonics generation, four-wave mixing, Kerr, and other nonlinear effects. In this paper we theoretically analyze the optical heterodyne detection (OHD) technique of measuring the optical Kerr effect (OKE) in two-dimensional crystals and show how to relate the quantities measured in such experiments with components of the third-order conductivity tensor σαβ γ δ (3 )(ω1,ω2,ω3) of the two-dimensional crystal. Using results of a recently developed quantum theory of the third-order nonlinear electrodynamic response of graphene, we analyze the frequency, charge carrier density, temperature, and other dependencies of the OHD-OKE response of this material. We compare our results with a recent OHD-OKE experiment in graphene and find good agreement between the theory and experiment.
Energy Technology Data Exchange (ETDEWEB)
Chandrasekhar, S [Chicago Univ., Ill. (USA)
1976-02-10
Teukolsky's equation, governing the perturbations (scalar, electromagnetic, and gravitational) of the Kerr black hole, is transformed, by a simple change of variables, in a manner such that there is formally no difference in the treatments of the axisymmetric and the non-axisymmetric modes: the role of 'm' is effectively eliminated. By considering in detail the case of electromagentic perturbations it is shown how, in all cases, the problems can be reduced to problems in the theory of penetration of one dimensional potential barriers with, however, certain novel features. The phenomenon of super-radiance, peculiar to the Kerr metric, emerges, for example, in an unexpected guise. The case of scalar perturbations is considered briefly in an appendix.
Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state.
Okada, Ken N; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori
2016-07-20
Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit.
Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures.
Széchenyi, Gábor; Vigh, Máté; Kormányos, Andor; Cserti, József
2016-09-21
To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model.
Transfer matrix approach for the Kerr and Faraday rotation in layered nanostructures
International Nuclear Information System (INIS)
Széchenyi, Gábor; Vigh, Máté; Cserti, József; Kormányos, Andor
2016-01-01
To study the optical rotation of the polarization of light incident on multilayer systems consisting of atomically thin conductors and dielectric multilayers we present a general method based on transfer matrices. The transfer matrix of the atomically thin conducting layer is obtained using the Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle and for the ellipticity of the reflected (transmitted) light as a function of the incident angle and polarization of the light. The method is demonstrated by calculating the Kerr (Faraday) angle for bilayer graphene in the quantum anomalous Hall state placed on the top of dielectric multilayers. The optical conductivity of the bilayer graphene is calculated in the framework of a four-band model. (paper)
A Monte Carlo Code for Relativistic Radiation Transport Around Kerr Black Holes
Schnittman, Jeremy David; Krolik, Julian H.
2013-01-01
We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.
Higher Dimensional Kerr-Schild Spacetimes with (A)dS Background
Czech Academy of Sciences Publication Activity Database
Málek, T.; Pravda, Vojtěch
2011-01-01
Roč. 314, - (2011), 012111 ISSN 1742-6588. [Spanish Relativity Meeting (ERE 2010). Granada, 06.09.2010-10.09.2010] R&D Projects: GA ČR GAP203/10/0749 Institutional research plan: CEZ:AV0Z10190503 Keywords : Kerr-Schild metrics * Einstein equations Subject RIV: BA - General Mathematics http://iopscience.iop.org/1742-6596/314/1/012111
Non-static nuclear forces in a Kerr-Newman background space
International Nuclear Information System (INIS)
Radmore, P.M.
1978-01-01
In the Kerr-Newman background space, an explicit expression for the source term due to a particle moving along a geodesic near the event horizon in the equatorial plane of the black hole is found. This is used, together with the solutions of the Klein-Gordon equation near the event horizon (found elsewhere) to show that the meson field near the black hole vanishes as the source crosses the event horizon. (author)
Improvement in spatial frequency characteristics of magneto-optical Kerr microscopy
Ogasawara, Takeshi
2017-10-01
The spatial resolution of a conventional magneto-optical Kerr microscope, compared with those of conventional optical microscopes, inevitably deteriorates owing to oblique illumination. An approach to obtaining the maximum spatial resolution using multiple images with different illumination directions is demonstrated here. The method was implemented by rotating the illumination path around the optical axis using a motorized stage. The Fourier transform image of the observed magnetic domain indicates that the spatial frequency component that is lost in the conventional method is restored.
Comparative Study of FDTD-Adopted Numerical Algorithms for Kerr Nonlinearities
DEFF Research Database (Denmark)
Maksymov, Ivan S.; Sukhorukov, Andrey A.; Lavrinenko, Andrei
2011-01-01
Accurate finite-difference time-domain (FDTD) modeling of optical pulse propagation in nonlinear media usually implies the use of auxiliary differential equation (ADE) techniques. The updating of electric field in full-vectorial 3-D ADE FDTD modeling of the optical Kerr effect and two-photon abso...... approaches. Such schemes can significantly reduce the CPU time for nonlinear computations, especially in 3-D models....
Realization of all-optical switch and diode via Raman gain process using a Kerr field
Abbas, Muqaddar; Qamar, Sajid; Qamar, Shahid
2016-08-01
The idea of optical photonic crystal, which is generated using two counter-propagating fields, is revisited to study gain-assisted all-optical switch and diode using Kerr field. Two counter-propagating fields with relative detuning Δ ν generate standing-wave field pattern which interacts with a four-level atomic system. The standing-wave field pattern acts like a static photonic crystal for Δ ν =0 , however, it behaves as a moving photonic crystal for Δ ν \
Haunted Kaluza universe with four-dimensional Lorentzian flat, Kerr, and Taub-NUT slices
International Nuclear Information System (INIS)
Ivanov, Rossen I.; Prodanov, Emil M.
2005-01-01
The duality between the original Kaluza's theory and Klein's subsequent modification is duality between slicing and threading decomposition of the five-dimensional spacetime. The field equations of the original Kaluza's theory lead to the interpretation of the four-dimensional Lorentzian Kerr and Taub-NUT solutions as resulting from static electric and magnetic charges and dipoles in the presence of ghost matter and constant dilaton, which models Newton's constant
Mundos Possíveis de Michel Vaillant: Altermundismo nas Histórias em Quadrinhos de Automobilismo
Directory of Open Access Journals (Sweden)
Rafael Duarte Oliveira Venancio
2014-07-01
Full Text Available O presente artigo deseja observar como a história em quadrinhos sobre automobilismo, notadamente a do personagem Michel Vaillant, consegue engendrar, em sua narrativa, mundos possíveis que, mesmo com atributos ficcionais, se vinculam à referencialidade dos fatos ocorridos no esporte. Utilizando-se o arcabouço teórico de Umberto Eco e de David Lewis, o objetivo aqui é refletir acerca desse exercício de isomorfismo lingüístico, bem como desvelar as estratégias altermundistas utilizadas.
On the Bargmann-Michel-Telegdi equations, and spin-orbit coupling: A tribute to Raymond Stora
Duval, Christian
2016-11-01
The Bargmann-Michel-Telegdi equations describing the motions of a spinning, charged, relativistic particle endowed with an anomalous magnetic moment in an electromagnetic field, are reconsidered. They are shown to duly stem from the linearization of the characteristic distribution of a presymplectic structure refining the original one of Souriau. In this model, once specialized to the case of a static electric-like field, the angular momentum and energy given by the associated moment map now correctly restore the spin-orbit coupling term. This is the state-of-the-art of unfinished joint work with Raymond Stora.
A crítica genealógica de Michel Foucault às governamentalidades do liberarismo
Nunes, Nei Antonio
2012-01-01
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Programa de Pós-Graduação em Sociologia Política, Florianópolis, 2012 O objetivo principal deste trabalho é explicitar/analisar A Crítica genealógica de Michel Foucault às governamentalidades do liberalismo. No primeiro capítulo, procuramos realizar uma discussão metodológica e, desse modo, evidenciar o instrumental genealógico do teórico francês, dando ênfase à explicitação das categorias ce...
Holographic description of Kerr-Bolt-AdS-dS spacetimes
International Nuclear Information System (INIS)
Chen, B.; Ghezelbash, A.M.; Kamali, V.; Setare, M.R.
2011-01-01
We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.
Holographic description of Kerr-Bolt-AdS-dS spacetimes
Energy Technology Data Exchange (ETDEWEB)
Chen, B., E-mail: bchen01@pku.edu.c [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, and Center for High Energy Physics, Peking University, Beijing 100871 (China); Ghezelbash, A.M., E-mail: masoud.ghezelbash@usask.c [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Kamali, V., E-mail: vkamali1362@gmail.co [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of); Setare, M.R., E-mail: rezakord@ipm.i [Department of Campus of Bijar, Kurdistan University, Bijar (Iran, Islamic Republic of)
2011-07-01
We show that there exists a holographic 2D CFT description of a Kerr-Bolt-AdS-dS spacetime. We first consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt-AdS-dS spacetimes and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual CFT descriptions of these black holes. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction. Furthermore we study the holographic description of the generic four-dimensional non-extremal Kerr-Bolt-AdS-dS black holes. We find that if focusing on the near-horizon region, for the massless scalar scattering in the low-frequency limit, the radial equation could still be rewritten as the SL(2,R) quadratic Casimir, suggesting the existence of dual 2D description. We read the temperatures of the dual CFT from the conformal coordinates and obtain the central charges by studying the near-horizon geometry of near-extremal black holes. We recover the macroscopic entropy from the microscopic counting. We also show that for the super-radiant scattering, the retarded Green's functions and the corresponding absorption cross sections are in perfect match with CFT prediction.
ODYSSEY: A PUBLIC GPU-BASED CODE FOR GENERAL RELATIVISTIC RADIATIVE TRANSFER IN KERR SPACETIME
Energy Technology Data Exchange (ETDEWEB)
Pu, Hung-Yi [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No. 1, Taipei 10617, Taiwan (China); Yun, Kiyun; Yoon, Suk-Jin [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of); Younsi, Ziri [Institut für Theoretische Physik, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main (Germany)
2016-04-01
General relativistic radiative transfer calculations coupled with the calculation of geodesics in the Kerr spacetime are an essential tool for determining the images, spectra, and light curves from matter in the vicinity of black holes. Such studies are especially important for ongoing and upcoming millimeter/submillimeter very long baseline interferometry observations of the supermassive black holes at the centers of Sgr A* and M87. To this end we introduce Odyssey, a graphics processing unit (GPU) based code for ray tracing and radiative transfer in the Kerr spacetime. On a single GPU, the performance of Odyssey can exceed 1 ns per photon, per Runge–Kutta integration step. Odyssey is publicly available, fast, accurate, and flexible enough to be modified to suit the specific needs of new users. Along with a Graphical User Interface powered by a video-accelerated display architecture, we also present an educational software tool, Odyssey-Edu, for showing in real time how null geodesics around a Kerr black hole vary as a function of black hole spin and angle of incidence onto the black hole.
Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Bambi, Cosimo; Nampalliwar, Sourabh [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Cárdenas-Avendaño, Alejandro [Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Dauser, Thomas [Remeis Observatory and ECAP, Universität Erlangen-Nürnberg, D-96049 Bamberg (Germany); García, Javier A., E-mail: bambi@fudan.edu.cn [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
2017-06-20
We present the first X-ray reflection model for testing the assumption that the metric of astrophysical black holes is described by the Kerr solution. We employ the formalism of the transfer function proposed by Cunningham. The calculations of the reflection spectrum of a thin accretion disk are split into two parts: the calculation of the transfer function and the calculation of the local spectrum at any emission point in the disk. The transfer function only depends on the background metric and takes into account all the relativistic effects (gravitational redshift, Doppler boosting, and light bending). Our code computes the transfer function for a spacetime described by the Johannsen metric and can easily be extended to any stationary, axisymmetric, and asymptotically flat spacetime. Transfer functions and single line shapes in the Kerr metric are compared to those calculated from existing codes to check that we reach the necessary accuracy. We also simulate some observations with NuSTAR and LAD/eXTP and fit the data with our new model to show the potential capabilities of current and future observations to constrain possible deviations from the Kerr metric.
Kerr-de Sitter spacetime, Penrose process, and the generalized area theorem
Bhattacharya, Sourav
2018-04-01
We investigate various aspects of energy extraction via the Penrose process in the Kerr-de Sitter spacetime. We show that the increase in the value of a positive cosmological constant, Λ , always reduces the efficiency of this process. The Kerr-de Sitter spacetime has two ergospheres associated with the black hole and the cosmological event horizons. We prove by analyzing turning points of the trajectory that the Penrose process in the cosmological ergoregion is never possible. We next show that in this process both the black hole and cosmological event horizons' areas increase, and the latter becomes possible when the particle coming from the black hole ergoregion escapes through the cosmological event horizon. We identify a new, local mass function instead of the mass parameter, to prove this generalized area theorem. This mass function takes care of the local spacetime energy due to the cosmological constant as well, including that which arises due to the frame-dragging effect due to spacetime rotation. While the current observed value of Λ is quite small, its effect in this process could be considerable in the early Universe scenario where its value is much larger, where the two horizons could have comparable sizes. In particular, the various results we obtain here are also evaluated in a triply degenerate limit of the Kerr-de Sitter spacetime we find, in which radial values of the inner, the black hole and the cosmological event horizons are nearly coincident.
Ghasemi, M.; Tavassoly, M. K.; Nourmandipour, A.
2017-12-01
In this paper, we investigate the possibility of entanglement swapping between two independent nonperfect cavities consisting of an atom with finite lifetime of atomic levels (as two independent sources of dissipation), which interacts with a quantized electromagnetic field in the presence of detuning and Kerr medium. In fact, there is no direct interaction between the two atoms, therefore, no entanglement exists between them. We use the Bell state measurement performed on the photons leaving the cavities to swap the entanglement stored between the atom-fields in each cavity into atom-atom. Our motivation comes from the fact that two-qubit entangled states are of great interest for quantum information science and technologies. We discuss the effect of the initial state of the system, the detuning parameter, the Kerr medium and the two dissipation sources on the swapped entanglement to atom-atom. We interestingly find that when the atomic decay rates and photonic leakages from the cavities are equal, our system behaves as an ideal system with no dissipation. Our results show that it is possible to create a long-living atom-atom maximally entangled state in the presence of Kerr effect and dissipation; we determine these conditions in detail and also establish the final atom-atom Bell state.
Photon blockade in optomechanical systems with a position-modulated Kerr-type nonlinear coupling
Zhang, X. Y.; Zhou, Y. H.; Guo, Y. Q.; Yi, X. X.
2018-03-01
We explore the photon blockade in optomechanical systems with a position-modulated Kerr-type nonlinear coupling, i.e. H_int˜\\hat{a}\\dagger2\\hat{a}^2(\\hat{b}_1^\\dagger+\\hat{b}_1) . We find that the Kerr-type nonlinear coupling can enhance the photon blockade greatly. We evaluate the equal-time second-order correlation function of the cavity photons and find that the optimal photon blockade does not happen at the single photon resonance. By working within the few-photon subspace, we get an approximate analytical expression for the correlation function and the condition for the optimal photon blockade. We also find that the photon blockade effect is not always enhanced as the Kerr-type nonlinear coupling strength g 2 increases. At some values of g 2, the photon blockade is even weakened. For the system we considered here, the second-order correlation function can be smaller than 1 even in the unresolved sideband regime. By numerically simulating the master equation of the system, we also find that the thermal noise of the mechanical environment can enhance the photon blockade. We give out an explanation for this counter-intuitive phenomenon qualitatively.
Tori sequences as remnants of multiple accreting periods of Kerr SMBHs
Pugliese, D.; Stuchlík, Z.
2018-03-01
Super-massive black holes (SMBHs) hosted in active galactic nuclei (AGNs) can be characterized by multi-accreting periods as the attractors interact with the environment during their life-time. These multi-accretion episodes should leave traces in the matter orbiting the attractor. Counterrotating and even misaligned structures orbiting around the SMBHs would be consequences of these episodes. Our task in this work is to consider situations where such accretions occur and to trace their remnants represented by several toroidal accreting fluids, corotating or counterrotating relative to the central Kerr attractor, and created in various regimes during the evolution of matter configurations around SMBHs. We focus particularly on the emergence of matter instabilities, i.e., tori collisions, accretion onto the central Kerr black hole, or creation of jet-like structures (proto-jets). Each orbiting configuration is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluid. We prove that sequences of configurations and hot points, where an instability occurs, characterize the Kerr SMBHs, depending mainly on their spin-mass ratios. The occurrence of tori accretion or collision are strongly constrained by the fluid rotation with respect to the central black hole and the relative rotation with respect to each other. Our investigation provides characteristic of attractors where traces of multi-accreting episodes can be found and observed.
International Nuclear Information System (INIS)
Torres-Torres, C.; García-Cruz, M.L.; Castañeda, L.; Rangel Rojo, R.; Tamayo-Rivera, L.; Maldonado, A.; Avendaño-Alejo, M.
2012-01-01
Chromium doped zinc oxide thin solid films were deposited on soda–lime glass substrates. The photoconductivity of the material and its influence on the optical behavior was evaluated. A non-alkoxide sol–gel synthesis approach was used for the preparation of the samples. An enhancement of the photoluminescence response exhibited by the resulting photoconductive films with embedded chromium nanoclusters is presented. The modification in the photoconduction induced by a 445 nm wavelength was measured and then associated with the participation of the optical absorptive response. In order to investigate the third order optical nonlinearities of the samples, a standard time-resolved Optical Kerr Gate configuration with 80 fs pulses at 830 nm was used and a quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. We estimate that from the inclusion of Cr nanoclusters into the sample results a strong optical Kerr effect originated by quantum confinement. The large photoluminescence response and the important refractive nonlinearity of the photoconductive samples seem to promise potential applications for the development of multifunctional all-optical nanodevices. - Highlights: ► Enhancement in photoluminescence for chromium doped zinc oxide films is presented. ► A strong and ultrafast optical Kerr effect seems to result from quantum confinement. ► Photoconductive properties for optical and optoelectronic functions were observed.
Energy Technology Data Exchange (ETDEWEB)
Torres-Torres, C., E-mail: crstorres@yahoo.com.mx [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, Mexico, DF 07738 (Mexico); Garcia-Cruz, M.L. [Centro de Investigacion en Dispositivos Semiconductores, Benemerita Universidad Autonoma de Puebla, A. P. J-48, Puebla 72570, Mexico (Mexico); Castaneda, L., E-mail: luisca@sirio.ifuap.buap.mx [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, A. P. J-48, Puebla 72570, Mexico (Mexico); Rangel Rojo, R. [CICESE/Depto. de Optica, A. P. 360, Ensenada, BC 22860 (Mexico); Tamayo-Rivera, L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, DF 01000 (Mexico); Maldonado, A. [Depto. de Ing. Electrica, CINVESTAV IPN-SEES, A. P. 14740, Mexico DF 07000 (Mexico); Avendano-Alejo, M., E-mail: imax_aa@yahoo.com.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, A. P. 70-186, 04510, DF (Mexico); and others
2012-04-15
Chromium doped zinc oxide thin solid films were deposited on soda-lime glass substrates. The photoconductivity of the material and its influence on the optical behavior was evaluated. A non-alkoxide sol-gel synthesis approach was used for the preparation of the samples. An enhancement of the photoluminescence response exhibited by the resulting photoconductive films with embedded chromium nanoclusters is presented. The modification in the photoconduction induced by a 445 nm wavelength was measured and then associated with the participation of the optical absorptive response. In order to investigate the third order optical nonlinearities of the samples, a standard time-resolved Optical Kerr Gate configuration with 80 fs pulses at 830 nm was used and a quasi-instantaneous pure electronic nonlinearity without the contribution of nonlinear optical absorption was observed. We estimate that from the inclusion of Cr nanoclusters into the sample results a strong optical Kerr effect originated by quantum confinement. The large photoluminescence response and the important refractive nonlinearity of the photoconductive samples seem to promise potential applications for the development of multifunctional all-optical nanodevices. - Highlights: Black-Right-Pointing-Pointer Enhancement in photoluminescence for chromium doped zinc oxide films is presented. Black-Right-Pointing-Pointer A strong and ultrafast optical Kerr effect seems to result from quantum confinement. Black-Right-Pointing-Pointer Photoconductive properties for optical and optoelectronic functions were observed.
“A UTOPIA DE UM CORPO INCORPÓREO”: corpo, poder e saber em Michel de Foucault
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Assis Daniel Gomes
2016-12-01
En este trabajo se reflexiona, de manera bien introductoria, acerca de algunas preocupaciones planteadas por Michel Foucault, en especial lo que él llama disciplinalization y utopía del cuerpo. Deducimos que estos están influenciados por la filosofía post-sartreana, participan las afecciones resultantes a partir de mayo de 1968 y un retorno a la filosofía de Nietzsche. Este filósofo de la transgresión en tela de juicio los supuestos hasta ahora planteados por la filosofía perspectiva marxista, vinculadas al concepto de lucha de clases y militante función intelectual (Sartre, que pensar en el cuerpo y el poder. Por último, Foucault refleja cómo construir cierta sociedad disciplinaria, según las convenciones dadas paraliza el cuerpo, inventa y dominado por ciertos intereses permeadas por relaciones de micro-poder. Palabras clave: Cuerpo; El Poder-saber; Michel Foucault.
Dinges, Martin
2009-01-01
In the English speaking world there is no lack of books or collections of essays somehow related to the work of Michel Foucault. One only has to consider the enormous flow of publications on « Gouvernementality » easily accessible in Current Contents. But the publication under review was only possible in France. In accordance with Michel Foucault's own way to do philosophy and politics, this book combines in a very interesting way different approaches to his seminal work about prisons : The b...
Francisca Tomé da Silva; Lucas da Silva Campos; Roberto de Sousa Melo; Tayson Cristien Nobre da Costa; Daniel Paiva Mendes
2017-01-01
Esse artigo teve como objetivo analisar a estrutura e situação econômico-financeira do capital de giro de uma empresa S/A, sob a óptica do modelo de Michel Fleuriet, que propicia uma análise dinâmica financeira. Com a reclassificação das contas, identificou-se três variáveis necessárias pelo modelo de Michel Fleuriet: necessidade de capital de giro (NCG), capital de giro (CDG) e saldo de tesouraria (ST). A pesquisa foi realizada nas demonstrações financeiras padronizadas (DFP) referentes aos ...
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Ana Paula Barbosa-Fohrmann
2017-02-01
Full Text Available First, this paper will approach the meanings of segregation (or exclusion, integration and inclusion grounded on the interpretation of several provisions of key international documents. Secondly, it intends to overcome the legal analysis and examine Michel Foucault’s and Martha Nussbaum’s discourses on disabilities. Michel Foucault, by means of a historical criticism, focuses his analysis on the medical model of segregation (or exclusion while Martha Nussbaum proposes a social model that intends to be more inclusive of persons with disabilities. The medical model of integration will not be tackled in this paper.
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Cintya Regina Ribeiro
2011-12-01
Full Text Available O presente trabalho visa problematizar a suposta constituição virtuosa entre educação e conhecimento oriunda de certa herança cultural da modernidade ocidental. A problemática ancora-se na indagação difusa, porém insistente, a ecoar no campo educacional: "o que é o ato do pensar, em educação, na contemporaneidade?". A tomada das condições atuais do pensamento como um problema de pesquisa educacional coloca em questão a histórica articulação entre conhecimento e pensamento reflexivo, obrigando ao confronto de certos amálgamas pedagógicos caros ao campo educacional moderno. Tal enfrentamento se realiza na companhia dos pensadores Michel Foucault e Friedrich Nietzsche, dada a relevância estratégica de suas produções, particularmente acerca da linguagem, da produção da verdade e de suas implicações nos modos de conhecer e pensar. Busca-se operacionalizar uma crítica da linguagem em direção a uma crítica do pensamento em educação, na chave de uma problematização ético-política. Nesse trabalho, tal plataforma analítica configura-se a partir das discussões de Michel Foucault - tanto em relação à questão do pensamento do fora, tal como elaborada por Maurice Blanchot, como em relação ao pensamento da diferença, tal como formulado por Gilles Deleuze. Sugerimos que a exploração desse debate possa atuar como um exercício de exterioridade ou de pensamento diferencial no jogo com o conhecimento e com o pensamento reflexivo presentes no campo educacional - seja no âmbito dos fazeres pedagógicos cotidianos da escola, seja no campo da produção da pesquisa educacional.This study aims to discuss the supposed virtuous constitution of education and knowledge originated from a certain cultural heritage of Western modernity. The study's problematic is anchored in the diffuse but insistent question which echoes in the educational field: "what is the act of thinking in education in contemporary times?". Studying the
CONTRIBUIÇÕES DO PENSAMENTO DE MICHEL MAFFESOLI PARA PESQUISA EM ENFERMAGEM E SAÚDE
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Rosane Gonçalves Nistchke
2017-01-01
Full Text Available Objetivo: realizar un análisis de la producción científica en el área de la Enfermería y de la Salud que adoptó el referencial teórico y metodológico de Michel Maffesoli, así como reflexionar sobre sus contribuciones a la enfermería y salud. Método: revisión integrativa de literatura, a partir de publicaciones científicas del área de la Salud, indexadas en las bases de datos SciELO ® , BVS, Scopus ® , CINAHL ® , PubMed ® , Web of Science ® . En el presente trabajo se analizaron los resultados obtenidos en el análisis de los resultados obtenidos en el estudio. Se empleó la palabra “Maffesoli”, teniendo como criterios de inclusión ser artículos completos, originales o de reflexión, que aplicaron el referencial teórico de Michel Maffesoli en el análisis o discusión de los datos, disponibles en los idiomas portugués, inglés, español y francés. Resultados : se seleccionaron 30 artículos, siendo gran parte de ellos con abordaje cualitativo y oriundos de la enfermería. Las nociones más presentes en los estudios fueron cotidianos, ética de la estética, tribu, potencia, juego doble, posmodernidad, los cuales abordaron lo cotidiano en sus diferentes escenarios de cuidado. Se expresa la importancia de estar atento a los aspectos subjetivos de lo cotidiano, considerando su complejidad, posibilitando nuevos y otros modos de estar-juntos. Conclusión : el pensamiento de Michel Maffesoli contribuye a la construcción del conocimiento en enfermería y salud, indicando caminos en las dimensiones del cuidado, en el campo académico y profesional, a partir del cotidiano de las personas, resignificando el cuidado que va más allá de la técnica, nos cambia la mirada y la dirección, para que podamos estar en sintonía con las diferentes situaciones del vivir y del convivir, abandonando el des-envolvimiento, para involucrarnos con un cuidado afectivo, el que toca, siendo, por lo tanto, efectivo.
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Jardel Sander
2010-08-01
Full Text Available Este artigo busca discutir as influências das ideias de Michel Foucault - sua caixa de ferramentas conceituais - na reforma psiquiátrica brasileira. Nesse sentido, parte-se de um olhar mais amplo sobre o projeto do autor, buscando identificar sua atualidade no cenário da saúde mental brasileira. Para tanto, traça-se um percurso histórico que retoma, brevemente, os acontecimentos do final dos anos 1970 no Brasil até alcançar os dias atuais. O esforço é justamente o de colocar em questão a necessidade de outras ferramentas conceituais, no intuito de esclarecer as condições de possibilidade de noções como as de loucura, doença mental e desrazão, em busca de uma relação porosa com o Fora (Dehors. Sendo assim, busca-se refletir sobre a importância das artes, em sua potência de criação e invenção, nesse processo, como possível fornecedora de ferramentas de trabalho.This paper discusses the influences of Michel Foucault's ideas - its conceptual toolbox - to the Brazilian psychiatric reform, that composes the current scenario of mental health in Brazil. It is made a historic rescue retaking, although shortly, the events of the late 1970s in Brazil. Subsequently, it is questioned these changes actuality, as well as the need for further conceptual tools in order to point possibility conditions for notions such as madness, mental illness and déraison, seeking for a relationship with the outside (dehors. It is concluded by emphasizing the importance of arts (its creation and invention potency, in the process of constructing a new conceptual toolbox.
Post-closure permit application for the Kerr Hollow Quarry at the Y-12 plant
International Nuclear Information System (INIS)
1995-06-01
The Kerr Hollow Quarry (KHQ) is located on U.S. Department of Energy (DOE) property at the Y-12 Plant, Oak Ridge, Tennessee. The Oak Ridge Y-12 Plant was built by the U.S. Army Corps of Engineers in 1943 as part of the Manhattan Project. Until 1992, the primary mission of the Y-12 Plant was the production and fabrication of nuclear weapons components. Activities associated with these functions included production of lithium compounds, recovery of enriched uranium from scrap material, and fabrication of uranium and other materials into finished parts for assemblies. The Kerr Hollow Quarry was used for waste disposal of a variety of materials including water-reactive and shock-sensitive chemicals and compressed gas cylinders. These materials were packaged in various containers and sank under the water in the quarry due to their great weight. Disposal activities were terminated in November, 1988 due to a determination by the Tennessee Department of Environment and Conservation that the quarry was subject to regulations under the Resource Conservation and Recovery Act of 1993. Methods of closure for the quarry were reviewed, and actions were initiated to close the quarry in accordance with closure requirements for interim status surface impoundments specified in Tennessee Rules 1200-1-11-.05(7) and 1200-1-11-.05(11). As part of these actions, efforts were made to characterize the physical and chemical nature of wastes that had been disposed of in the quarry, and to remove any containers or debris that were put into the quarry during waste disposal activities. Closure certification reports (Fraser et al. 1993 and Dames and Moore 1993) document closure activities in detail. This report contains the post-closure permit application for the Kerr Hollow Quarry site
Testing a class of non-Kerr metrics with hot spots orbiting SgrA*
International Nuclear Information System (INIS)
Liu, Dan; Li, Zilong; Bambi, Cosimo
2015-01-01
SgrA*, the supermassive black hole candidate at the Galactic Center, exhibits flares in the X-ray, NIR, and sub-mm bands that may be interpreted within a hot spot model. Light curves and images of hot spots orbiting a black hole are affected by a number of special and general relativistic effects, and they can be potentially used to check whether the object is a Kerr black hole of general relativity. However, in a previous study we have shown that the relativistic features are usually subdominant with respect to the background noise and the model-dependent properties of the hot spot, and eventually it is at most possible to estimate the frequency of the innermost stable circular orbit. In this case, tests of the Kerr metric are only possible in combination with other measurements. In the present work, we consider a class of non-Kerr spacetimes in which the hot spot orbit may be outside the equatorial plane. These metrics are difficult to constrain from the study of accretion disks and indeed current X-ray observations of stellar-mass and supermassive black hole candidates cannot put interesting bounds. Here we show that near future observations of SgrA* may do it. If the hot spot is sufficiently close to the massive object, the image affected by Doppler blueshift is brighter than the other one and this provides a specific observational signature in the hot spot's centroid track. We conclude that accurate astrometric observations of SgrA* with an instrument like GRAVITY should be able to test this class of metrics, except in the more unlikely case of a small viewing angle
Kerr microscopy study of exchange-coupled FePt/Fe exchange spring magnets
Energy Technology Data Exchange (ETDEWEB)
Hussain, Zaineb; Kumar, Dileep [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)
2017-05-15
Magnetization reversal and magnetic microstructure of top soft magnetic layer (Fe) in exchange spring coupled L1{sub 0} FePt/Fe is studied using high resolution Kerr microscopy. With remnant state of the hard magnetic layer (L1{sub 0} FePt) as initial condition, magnetization loops along with magnetic domains are recorded for the top soft magnetic layer (Fe) using Kerr microscopy. Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. It is also observed that one can tune the magnitude of hysteresis shift by reaching the remanent state from different saturating fields (H{sub SAT}) and also by varying the angle between measuring field and H{sub SAT}. The hysteresis loops and magnetic domains of top soft Fe layer demonstrate unambiguously that soft magnetic layer at remanent state in such exchange coupled system is having unidirectional anisotropy. An analogy is drawn and the observations are explained in terms of established model of exchange bias phenomena framed for field-cooled ferromagnetic - antiferromagnetic bilayer systems. - Highlights: • Kerr microscopy of top soft magnetic Fe layer in exchange spring coupled L1{sub 0} FePt (30 nm)/Fe (22 nm) is reported. • Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. • Tuneable nature of magnitude of hysteresis shift is shown. • It is unambiguously shown that the top soft Fe magnetic layer at remanent state is having unidirectional anisotropy.
All-optical analog-to-digital converter based on Kerr effect in photonic crystal
Jafari, Dariush; Nurmohammadi, Tofiq; Asadi, Mohammad Javad; Abbasian, Karim
2018-05-01
In this paper, a novel all-optical analog-to-digital converter (AOADC) is proposed and simulated for proof of principle. This AOADC is designed to operate in the range of telecom wavelength (1550 nm). A cavity made of nonlinear Kerr material in photonic crystal (PhC), is designed to achieve an optical analog-to-digital conversion with 1 Tera sample per second (TS/s) and the total footprint of 42 μm2 . The simulation is done using finite-difference time domain (FDTD) method.
Pair production of scalar dyons in Kerr-Newman black holes
Chen, Chiang-Mei; Kim, Sang Pyo; Sun, Jia-Rui; Tang, Fu-Yi
2018-06-01
We study the spontaneous pair production of scalar dyons in the near extremal dyonic Kerr-Newman (KN) black hole, which contains a warped AdS3 structure in the near horizon region. The leading term contribution of the pair production rate and the absorption cross section ratio are also calculated using the Hamilton-Jacobi approach and the thermal interpretation is given. In addition, the holographic dual conformal field theories (CFTs) descriptions of the pair production rate and absorption cross section ratios are analyzed both in the J-, Q- and P-pictures respectively based on the threefold dyonic KN/CFTs dualities.
Ultrafast gated imaging of laser produced plasmas using the optical Kerr effect
International Nuclear Information System (INIS)
Symes, D. R.; Wegner, U.; Ahlswede, H.-C.; Streeter, M. J. V.; Gallegos, P. L.; Divall, E. J.; Rajeev, P. P.; Neely, D.; Smith, R. A.
2010-01-01
Optical imaging is a versatile diagnostic for investigations of plasmas generated under intense laser irradiation. Electro-optic gating techniques operating on the >100 ps timescale are commonly used to reduce the amount of light detected from self-emission of hot plasma or improve the temporal resolution of the detector. The use of an optical Kerr gate enables a superior dynamic range and temporal resolution compared to electronically gated devices. The application of this method for enhanced imaging of laser produced plasmas with gate time ∼100 fs is demonstrated, and the possibility to produce a sub-10 fs, high dynamic range 'all optical' streak camera is discussed.
Energy Technology Data Exchange (ETDEWEB)
Lan, X.G. [Southwest Jiaotong University, Quantum Optoelectronics Laboratory, Chengdu (China); China West Normal University, Institute of Theoretical Physics, Nanchong (China); Jiang, Q.Q. [China West Normal University, Institute of Theoretical Physics, Nanchong (China); Wei, L.F. [Southwest Jiaotong University, Quantum Optoelectronics Laboratory, Chengdu (China); Sun Yat-Sen University, State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Guangzhou (China)
2012-04-15
We apply the Damour-Ruffini-Sannan method to study the Hawking radiations of scalar and Dirac particles in non-stationary Kerr black holes under different tortoise coordinate transformations. We found that all the relevant Hawking radiation spectra show still the blackbody ones, while the Hawking temperatures are strongly related to the used tortoise coordinate transformations. The properties of these dependences are discussed analytically and numerically. Our results imply that proper selections of tortoise coordinate transformations should be important in the studies of Hawking radiations and the correct selection would be given by the experimental observations in the future. (orig.)
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Sakae Meguro
2016-05-01
Full Text Available An observation system of centimeter-order of view of magnetic domain with local magnetization direction was developed by designing a telecentric optical system of finite design through the extension of microscope technology. The field of view realized in the developed system was 1.40 × 1.05 cm as suppressing defocus and distortion. Detection of the local magnetization direction has become possible by longitudinal Kerr observation from the orthogonal two directions. This system can be applied to the domain observation of rough surface samples and time resolved analysis for soft magnetic materials such as amorphous foil strips and soft magnetic thin films.
Self-trapping of scalar and vector dipole solitary waves in Kerr media
International Nuclear Information System (INIS)
Zhong Weiping; Belic, Milivoj R.; Assanto, Gaetano; Malomed, Boris A.; Huang Tingwen
2011-01-01
We report solutions for expanding dipole-type optical solitary waves in two-dimensional Kerr media with the self-focusing nonlinearity, using exact analytical (Hirota) and numerical methods. Such localized beams carry intrinsic vorticity and exhibit symmetric shapes for both scalar and vector solitary modes. When vector beams are close to the scalar limit, simulations demonstrate their stability over propagation distances exceeding 50 diffraction lengths. In fact, the continuous expansion helps the vortical beams avoid the instability against the splitting, collapse, or decay, making them 'convectively stable' patterns.
A Killing tensor for higher dimensional Kerr-AdS black holes with NUT charge
International Nuclear Information System (INIS)
Davis, Paul
2006-01-01
In this paper, we study the recently discovered family of higher dimensional Kerr-AdS black holes with an extra NUT-like parameter. We show that the inverse metric is additively separable after multiplication by a simple function. This allows us to separate the Hamilton-Jacobi equation, showing that geodesic motion is integrable on this background. The separation of the Hamilton-Jacobi equation is intimately linked to the existence of an irreducible Killing tensor, which provides an extra constant of motion. We also demonstrate that the Klein-Gordon equation for this background is separable
Perturbative evolution of particle orbits around Kerr black holes: time-domain calculation
Energy Technology Data Exchange (ETDEWEB)
Lopez-Aleman, Ramon [Physical Sciences Department, University of Puerto Rico-Rio Piedras, San Juan, PR 00931 (Puerto Rico); Khanna, Gaurav [Natural Science Division, Long Island University, Southampton, NY 11968 (United States); Pullin, Jorge [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, LA 70803-4001 (United States)
2003-07-21
We consider the problem of the gravitational waves produced by a particle of negligible mass orbiting a Kerr black hole. We treat the Teukolsky perturbation equation in the time domain numerically as a 2 + 1 partial differential equation. We model the particle by smearing the singularities in the source term by the use of narrow Gaussian distributions. We have been able to reproduce earlier results for equatorial circular orbits that were computed using the frequency-domain formalism. The time-domain approach is however geared for a more general evolution, for instance of nearly geodesic orbits under the effects of radiation reaction.
Perturbative evolution of particle orbits around Kerr black holes: time-domain calculation
International Nuclear Information System (INIS)
Lopez-Aleman, Ramon; Khanna, Gaurav; Pullin, Jorge
2003-01-01
We consider the problem of the gravitational waves produced by a particle of negligible mass orbiting a Kerr black hole. We treat the Teukolsky perturbation equation in the time domain numerically as a 2 + 1 partial differential equation. We model the particle by smearing the singularities in the source term by the use of narrow Gaussian distributions. We have been able to reproduce earlier results for equatorial circular orbits that were computed using the frequency-domain formalism. The time-domain approach is however geared for a more general evolution, for instance of nearly geodesic orbits under the effects of radiation reaction
Jahanbakhsh, F.; Honarasa, G.
2018-04-01
The potential of nonharmonic systems has several applications in the field of quantum physics. The photon-added coherent states for annharmonic oscillators in a nonlinear Kerr medium can be used to describe some quantum systems. In this paper, the phase properties of these states including number-phase Wigner distribution function, Pegg-Barnett phase distribution function, number-phase squeezing and number-phase entropic uncertainty relations are investigated. It is found that these states can be considered as the nonclassical states.
Interferometric method to determine the Kerr constant of perspex and ZnSe
CSIR Research Space (South Africa)
Govender, P
2010-09-01
Full Text Available , (1999). [2] T. K. Ishii and A. Griffis, “Measurement of electro-optic effects in acrylic plastic”, Microwave and Optical Technology Letters, 4, 387-389(1991). [3] W. Kucharczyk, M. J. Gunning, R. E. Raab and C. Graham, “Interferometric investigation... to Determine the Kerr Constant of Perspex Patricia Govender1, 2, Dr. V.W. Couling1 1 UKZN Pietermaritzburg, King Edward Avenue, Scottsville, Pietermaritzburg 2 CSIR, DPSS, 3Meiring Naude Avenue Patricia Govender e-mail address: pgovender...
Hawking radiation screening and Penrose process shielding in the Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Mc Caughey, Eamon [Dublin Institute of Technology, School of Mathematical Sciences, Dublin 8 (Ireland)
2016-04-15
The radial motion of massive particles in the equatorial plane of a Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined. (orig.)
Grudtsyn, Ya. V.; Koribut, A. V.; Mikheev, L. D.; Trofimov, V. A.
2018-04-01
The mechanism of femtosecond pulse self-shortening in thin optical materials with Kerr nonlinearity is investigated. The experimentally observed spectral-angular distribution of the radiation intensity on the exit surface of a 1-mm-thick fused silica sample is compared with the results of numerical simulation based on solving the nonlinear Schrödinger equation for an electromagnetic wave with a transverse perturbation on the axis. Qualitative agreement between the calculated and experimental results confirms the hypothesis about the transient regime of multiple filamentation as a mechanism of femtosecond pulse self-shortening.
Unstable Mode Solutions to the Klein-Gordon Equation in Kerr-anti-de Sitter Spacetimes
Dold, Dominic
2017-03-01
For any cosmological constant {Λ = -3/ℓ2 r+2 > |a|ℓ}. We obtain an analogous result for Neumann boundary conditions if {5/4 < α < 9/4}. Moreover, in the Dirichlet case, one can prove that, for any Kerr-AdS spacetime violating the Hawking-Reall bound, there exists an open family of masses {α} such that the corresponding Klein-Gordon equation permits exponentially growing mode solutions. Our result adopts methods of Shlapentokh-Rothman developed in (Commun. Math. Phys. 329:859-891, 2014) and provides the first rigorous construction of a superradiant instability for negative cosmological constant.
Finster, F.; Kamran, N.; Smoller, J.; Yau, S.-T.
The Cauchy problem is considered for the massive Dirac equation in the non-extreme Kerr-Newman geometry, for smooth initial data with compact support outside the event horizon and bounded angular momentum. We prove that the Dirac wave function decays in L∞ {loc} at least at the rate t-5/6. For generic initial data, this rate of decay is sharp. We derive a formula for the probability p that the Dirac particle escapes to infinity. For various conditions on the initial data, we show that p = 0, 1 or 0 < p < 1. The proofs are based on a refined analysis of the Dirac propagator constructed in [4].
Flag-dipole and flagpole spinor fluid flows in Kerr spacetimes
Energy Technology Data Exchange (ETDEWEB)
Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [Universidade Federal do ABC, CMCC (Brazil); Cavalcanti, R. T., E-mail: rogerio.cavalcanti@ufabc.edu.br [Universidade Federal do ABC, CCNH (Brazil)
2017-03-15
Flagpole and flag-dipole spinors are particular classes of spinor fields that has been recently used in different branches of theoretical physics. In this paper, we study the possibility and consequences of these spinor fields to induce an underlying fluid flow structure in the background of Kerr spacetimes. We show that flag-dipole spinor fields are solutions of the equations of motion in this context. To our knowledge, this is the second time that this class of spinor field appears as a physical solution, the first one occurring as a solution of the Dirac equation in ESK gravities.
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)
2015-12-15
The coupled gravitational-electromagnetic quasinormal resonances of charged rotating Kerr-Newman black holes are explored. In particular, using the recently published numerical data of Dias et al. (Phys Rev Lett 114:151101, 2015), we show that the characteristic relaxation times τ ≡ 1/Iω{sub 0} of near-extremal Kerr-Newman black holes in the regime Q/r{sub +} ≤ 0.9 are described, to a very good degree of accuracy, by the simple universal relation τ x T{sub BH} = π{sup -1} (here Q/r{sub +}, and T{sub BH} are respectively the electric charge, horizon radius, and temperature of the Kerr-Newman black hole, and ω{sub 0} is the fundamental quasinormal resonance of the perturbed black-hole spacetime). (orig.)
International Nuclear Information System (INIS)
Bacha, Bakht Amin; Ghafoor, Fazal; Ahmad, Iftikhar; Rahman, A
2014-01-01
A four level double lambda-type atomic configuration is extended to polychromatic pump fields driven from the ground to the same excited hyperfine sublevel. Multiple superluminal regions are observed in the gain peak regions and between the two pairs of gain peak regions. Furthermore, the effect of cross Kerr nonlinearity is introduced in the system by applying an additional driving field. Large enhancement in the superluminality is observed as compared to the previously observed superluminality without the Kerr nonlinearity. The results clearly show a small negative group velocity of − 0.72 m s −1 with a negative time delay of −42.2 ms in the presence of the Kerr field. In this connection, useful theoretical techniques are presented for the enhancement of slow and fast light propagation. This generalized model is adjustable with the current applied technologies of cloaking devices and spacial mode images. (paper)
Properties of Linear Entropy in k-Photon Jaynes-Cummings Model with Stark Shift and Kerr-Like Medium
International Nuclear Information System (INIS)
Liao Qinghong; Wang Yueyuan; Liu Shutian; Ahmad, Muhammad Ashfaq
2010-01-01
The time evolution of the linear entropy of an atom in k-photon Jaynes-Cummings model is investigated taking into consideration Stark shift and Kerr-like medium. The effect of both the Stark shift and Kerr-like medium on the linear entropy is analyzed using a numerical technique for the field initially in coherent state and in even coherent state. The results show that the presence of the Kerr-like medium and Stark shift has an important effect on the properties of the entropy and entanglement. It is also shown that the setting of the initial state plays a significant role in the evolution of the linear entropy and entanglement. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Energy Technology Data Exchange (ETDEWEB)
Schee, Jan; Stuchlik, Zdenek [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre for Theoretical Physics and Astrophysics, Opava (Czech Republic)
2016-11-15
We study optical effects in quintessential Kerr black hole spacetimes corresponding to the limiting case of the equation-of-state parameter ω{sub q} = -1/3 of the quintessence. In dependence on the dimensionless quintessential field parameter c, we determine the black hole silhouette and the spectral line profiles of Keplerian disks generated in this special quintessential Kerr geometry, representing an extension of the general modifications of the Kerr geometry introduced recently by Ghasemi-Nodehi and Bambi (Eur. Phys. J. C 56:290, 2016). We demonstrate that due to the influence of the parameter c, the silhouette is almost homogeneously enlarged, and the spectral line profiles are redshifted with almost conserved shape. (orig.)
Nicolas Michel, Une économie de subsistances. Le Maroc précolonial, IFAO, Le Caire, 1997.
Directory of Open Access Journals (Sweden)
Sylvie Denoix
2004-11-01
Full Text Available Le titre de cet ouvrage peut apparaître paradoxal si l'on considère, comme le rappelle Nicolas Michel, que le Maroc, dès avant le XIXe siècle, était inséré dans une économie marchande internationale "faisant circuler dans tout le pays produits et espèces monétaires". En fait, les produits de première nécessité échappent au grand négoce et font plutôt l'objet d'un troc, d'un échange contre services, hors système monétaire. Néanmoins, dans un souci de rigueur méthodologique, l'auteur nous garde...
Clío, entre Freud y Lacan: El gesto psicoanalítico en Michel de Certeau
Directory of Open Access Journals (Sweden)
Andrés Freijomil
2010-12-01
Full Text Available A partir de los años 1970, el historiador francés Michel de Certeau (1925-1986 comenzó a indagar la naturaleza epistemológica de la historiografía a partir de varios campos del saber. Uno de los más importantes ha sido, sin duda, el psicoanálisis. A lo largo de una serie de ensayos publicados en revistas como Annales, Action poétique o Lettres de l'École, de Certeau examinó el legado freudiano, discutió con el Foucault de Historia de la locura y la tradición antropológica de Géza Roheim. De tal modo, lejos de aplicar el psicoanálisis a la historia, de Certeau más bien propuso resituar sus espacios metodológicos a fin de "elucidar" la especificidad de cada disciplina
Laffaille, P.; Feunteun, E.; Lefeuvre, J.-C.
2000-10-01
At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt marshes) of Mont Saint-Michel Bay. These and other comparable shallow marine coastal waters, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has been paid to the value of tidal salt marshes for fishes. Between March 1996 and April 1999, 120 tides were sampled in a tidal creek. A total of 31 species were caught. This community was largely dominated by mullets ( Liza ramada represent 87% of the total biomass) and sand gobies ( Pomatoschistus minutus and P. lozanoi represent 82% of the total numbers). These species and also Gasterosteus aculeatus , Syngnathus rostellatus, Dicentrarchus labrax, Mugil spp., Liza aurata and Sprattus sprattus were the most frequent species (>50% of monthly frequency of occurrence). In Europe, salt marshes and their creeks are flooded only during high spring tides. So, fishes only invade this environment during short immersion periods, and no species can be considered as marsh resident. But, the salt marsh was colonized by fish every time the tide reached the creek, and during the short time of flood, dominant fishes fed actively and exploited the high productivity. Nevertheless, this study shows that there is little interannual variation in the fish community and there are three ' seasons ' in the fish fauna of the marsh. Marine straggler and marine estuarine dependent species colonize marshes between spring (recruitment period in the bay) and autumn before returning into deeper adjacent waters. Estuarine fishes are present all year round with maximum abundances in the end of summer. The presence of fishes confirms that this kind of wetland plays an important trophic and nursery role for these species. Differences in densities and stages distribution of these species into Mont Saint-Michel systems (tidal mudflats, estuaries and tidal salt marshes) can reduce the trophic
Directory of Open Access Journals (Sweden)
Jaime Carmona-Fonseca
2006-12-01
Conclusión. Este sistema de ecuaciones lineales permitirá convertir unidades Michel (delta PH/hora en unidades EQM (U/g oxihemoglobina y viceversa, lo cual facilitará el trabajo en ambientes clínicos y epidemiológicos.
Energy Technology Data Exchange (ETDEWEB)
Girón-Sedas, J. A. [Departamento de Física, Universidad del Valle, AA 25360, Cali (Colombia); Centro de Investigación e Innovación en Bioinformática y Fotónica - CIBioFI, AA 25360 Cali (Colombia); Mejía-Salazar, J. R., E-mail: jrmejia3146@gmail.com [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP (Brazil); Moncada-Villa, E.; Porras-Montenegro, N. [Departamento de Física, Universidad del Valle, AA 25360, Cali (Colombia)
2016-07-18
We propose a way to enhance the transverse magneto-optical Kerr effect, by the excitation of resonant tunneling modes, in subwavelength trilayer structures featuring a dielectric slab sandwiched between two magneto-optical metallic layers. Depending on the magneto-optical layer widths, the proposed system may exhibit an extraordinary transverse magneto-optical Kerr effect, which makes it very attractive for the design and engineering of thin-film magneto-optical-based devices for future photonic circuits or fiber optical-communication systems.
Compact and high repetition rate Kerr-lens mode-locked 532 nm Nd:YVO4 laser
International Nuclear Information System (INIS)
Li, Zuohan; Peng, Jiying; Yuan, Ruixia; Yao, Jianquan; Zheng, Yi; Wang, Tongtong
2015-01-01
A compact and feasible CW Kerr-lens-induced mode-locked 532 nm Nd:YVO 4 laser system was experimentally demonstrated for the first time with theoretical analysis. Kerr-lens mode locking with intracavity second harmonic generation provides a promising method to generate a high-repetition-rate picosecond green laser. With an incident pump power of 6 W, the average output power of mode locking was 258 mW at a high repetition rate of 1.1 GHz. (paper)
International Nuclear Information System (INIS)
Cardoso, Vitor; Lemos, Jose P.S.
2003-01-01
In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra, and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss the possible connections between these results and black-hole-black-hole collisions at the speed of light. Our results show that during the high-speed collision of a nonrotating hole with a rotating one, at most 35% of the total energy can get converted into gravitational waves. This 35% efficiency occurs only in the most optimistic situation, that of a zero impact parameter collision, along the equatorial plane, with an almost extreme Kerr black hole. In the general situation, the total gravitational energy radiated is expected to be much less, especially if the impact parameter increases. Thus, if one is able to produce black holes at the CERN Large Hadron Collider, at most 35% of the partons' energy should be emitted during the so-called balding phase. This energy will be missing, since we do not have gravitational wave detectors able to measure such amplitudes. The collision at the speed of light between one rotating black hole and a nonrotating one or two rotating black holes turns out to be the most efficient gravitational wave generator in the Universe
Two-component vector solitons in defocusing Kerr-type media with spatially modulated nonlinearity
Energy Technology Data Exchange (ETDEWEB)
Zhong, Wei-Ping, E-mail: zhongwp6@126.com [Department of Electronic and Information Engineering, Shunde Polytechnic, Guangdong Province, Shunde 528300 (China); Texas A and M University at Qatar, P.O. Box 23874 Doha (Qatar); Belić, Milivoj [Texas A and M University at Qatar, P.O. Box 23874 Doha (Qatar); Institute of Physics, University of Belgrade, P.O. Box 57, 11001 Belgrade (Serbia)
2014-12-15
We present a class of exact solutions to the coupled (2+1)-dimensional nonlinear Schrödinger equation with spatially modulated nonlinearity and a special external potential, which describe the evolution of two-component vector solitons in defocusing Kerr-type media. We find a robust soliton solution, constructed with the help of Whittaker functions. For specific choices of the topological charge, the radial mode number and the modulation depth, the solitons may exist in various forms, such as the half-moon, necklace-ring, and sawtooth vortex-ring patterns. Our results show that the profile of such solitons can be effectively controlled by the topological charge, the radial mode number, and the modulation depth. - Highlights: • Two-component vector soliton clusters in defocusing Kerr-type media are reported. • These soliton clusters are constructed with the help of Whittaker functions. • The half-moon, necklace-ring and vortex-ring patterns are found. • The profile of these solitons can be effectively controlled by three soliton parameters.
Properties of a thin accretion disk around a rotating non-Kerr black hole
International Nuclear Information System (INIS)
Chen Songbai; Jing Jiliang
2012-01-01
We study the accretion process in the thin disk around a rotating non-Kerr black hole with a deformed parameter and an unbound rotation parameter. Our results show that the presence of the deformed parameter ε modifies the standard properties of the disk. For the case in which the black hole is more oblate than a Kerr black hole, the larger deviation leads to the smaller energy flux, the lower radiation temperature and the fainter spectra luminosity in the disk. For the black hole with positive deformed parameter, we find that the effect of the deformed parameter on the disk becomes more complicated. It depends not only on the rotation direction of the black hole and the orbit particles, but also on the sign of the difference between the deformed parameter ε and a certain critical value ε c . These significant features in the mass accretion process may provide a possibility to test the no-hair theorem in the strong-field regime in future astronomical observations.
Resonance spectrum of near-extremal Kerr black holes in the eikonal limit
International Nuclear Information System (INIS)
Hod, Shahar
2012-01-01
The fundamental resonances of rapidly rotating Kerr black holes in the eikonal limit are derived analytically. We show that there exists a critical value, μ c =√((15-√(193))/2 ), for the dimensionless ratio μ≡m/l between the azimuthal harmonic index m and the spheroidal harmonic index l of the perturbation mode, above which the perturbations become long lived. In particular, it is proved that above μ c the imaginary parts of the quasinormal frequencies scale like the black-hole temperature: ω I (n;μ>μ c )=2πT BH (n+1/2 ). This implies that for perturbations modes in the interval μ c I of the black hole becomes extremely long as the extremal limit T BH →0 is approached. A generalization of the results to the case of scalar quasinormal resonances of near-extremal Kerr-Newman black holes is also provided. In particular, we prove that only black holes that rotate fast enough (with MΩ≥2/5 , where M and Ω are the black-hole mass and angular velocity, respectively) possess this family of remarkably long-lived perturbation modes.
Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors
Energy Technology Data Exchange (ETDEWEB)
Schemm, E.R., E-mail: eschemm@alumni.stanford.edu [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Levenson-Falk, E.M. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Kapitulnik, A. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States); Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
2017-04-15
Highlights: • Polar Kerr effect (PKE) probes broken time-reversal symmetry (TRS) in superconductors. • Absence of PKE below Tc in CeCoIn{sub 5} is consistent with dx2-y2 order parameter symmetry. • PKE in the B phase of the multiphase superconductor UPt3 agrees with an E2u model. • Data on URu2Si2 show broken TRS and additional structure in the superconducting state. - Abstract: The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of {sup 3}He-B, all of the known or suspected chiral – that is to say time-reversal symmetry-breaking (TRSB) – superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.
Onset of superradiant instabilities in the composed Kerr-black-hole–mirror bomb
Directory of Open Access Journals (Sweden)
Shahar Hod
2014-09-01
Full Text Available It was first pointed out by Press and Teukolsky that a system composed of a spinning Kerr black hole surrounded by a reflecting mirror may develop instabilities. The physical mechanism responsible for the development of these exponentially growing instabilities is the superradiant amplification of bosonic fields confined between the black hole and the mirror. A remarkable feature of this composed black-hole–mirror-field system is the existence of a critical mirror radius, rmstat, which supports stationary (marginally-stable field configurations. This critical (‘stationary’ mirror radius marks the boundary between stable and unstable black-hole–mirror-field configurations: composed systems whose confining mirror is situated in the region rmrmstat are unstable (that is, there are confined field modes which grow exponentially over time. In the present paper we explore this critical (marginally-stable boundary between stable and explosive black-hole–mirror-field configurations. It is shown that the innermost (smallest radius of the confining mirror which allows the extraction of rotational energy from a spinning Kerr black hole approaches the black-hole horizon radius in the extremal limit of rapidly-rotating black holes. We find, in particular, that this critical mirror radius (which marks the onset of superradiant instabilities in the composed system scales linearly with the black-hole temperature.
New Einstein-Sasaki and Einstein spaces from Kerr-de Sitter
International Nuclear Information System (INIS)
Cvetic, M.; Lue, H.; Pope, C.N.; Page, Don N.
2009-01-01
In this paper, which is an elaboration of our results in Phys. Rev. Lett. 95:071101, 2005 (hep-th/0504225), we construct new Einstein-Sasaki spaces L p,q,r 1 ,...,r n-1 in all odd dimensions D = 2n+1 ≥ 5. They arise by taking certain BPS limits of the Euclideanised Kerr-de Sitter metrics. This yields local Einstein-Sasaki metrics of cohomogeneity n, with toric U(1) n+1 principal orbits, and n real non-trivial parameters. By studying the structure of the degenerate orbits we show that for appropriate choices of the parameters, characterised by the (n+1) coprime integers (p,q,r 1 ,...,r n-1 ), the local metrics extend smoothly onto complete and non-singular compact Einstein-Sasaki manifolds L p,q,r 1 ,...,r n-1 . We also construct new complete and non-singular compact Einstein spaces Λ p,q,r 1 ,...,r n in D = 2n+1 that are not Sasakian, by choosing parameters appropriately in the Euclideanised Kerr-de Sitter metrics when no BPS limit is taken.
Gyromagnetic ratio of charged Kerr-anti-de Sitter black holes
International Nuclear Information System (INIS)
Aliev, Alikram N
2007-01-01
We examine the gyromagnetic ratios of rotating and charged AdS black holes in four and higher spacetime dimensions. We compute the gyromagnetic ratio for Kerr-AdS black holes with an arbitrary electric charge in four dimensions and show that it corresponds to g = 2 irrespective of the AdS nature of the spacetime. We also compute the gyromagnetic ratio for Kerr-AdS black holes with a single angular momentum and with a test electric charge in all higher dimensions. The gyromagnetic ratio crucially depends on the dimensionless ratio of the rotation parameter to the curvature radius of the AdS background. At the critical limit, when the boundary Einstein universe is rotating at the speed of light, it exhibits a striking feature leading to g 2 regardless of the spacetime dimension. Next, we extend our consideration to include the exact metric for five-dimensional rotating charged black holes in minimal gauged supergravity. We show that the value of the gyromagnetic ratio found in the 'test-charge' approach remains unchanged for these black holes
Exact Stiffness for Beams on Kerr-Type Foundation: The Virtual Force Approach
Directory of Open Access Journals (Sweden)
Suchart Limkatanyu
2013-01-01
Full Text Available This paper alternatively derives the exact element stiffness equation for a beam on Kerr-type foundation. The shear coupling between the individual Winkler-spring components and the peripheral discontinuity at the boundaries between the loaded and the unloaded soil surfaces are taken into account in this proposed model. The element flexibility matrix is derived based on the virtual force principle and forms the core of the exact element stiffness matrix. The sixth-order governing differential compatibility of the problem is revealed using the virtual force principle and solved analytically to obtain the exact force interpolation functions. The matrix virtual force equation is employed to obtain the exact element flexibility matrix based on the exact force interpolation functions. The so-called “natural” element stiffness matrix is obtained by inverting the exact element flexibility matrix. One numerical example is utilized to confirm the accuracy and the efficiency of the proposed beam element on Kerr-type foundation and to show a more realistic distribution of interactive foundation force.
X-ray magneto-optic KERR effect studies of spring magnet heterostructures.
Energy Technology Data Exchange (ETDEWEB)
Kortright, J. B.; Kim, S.-K.; Fullerton, E. E.; Jiang, J. S.; Bader, S. D.
2000-11-01
The complex 3-dimensional magnetization reversal behavior of Sin-Co/Fe exchange spring films is used to test the sensitivity of different resonant soft x-ray magneto-optical Kerr effect (MOKE) measurements to changes in longitudinal and transverse moments within the SOIIFe layer and to changes in these moments in depth within the Fe layer. As in the visible MOKE, changes in longitudinal and net transverse moments are resolved by measuring both Kerr rotation and intensity loops in the near the Fe 2p core resonance. These x-ray MOKE signals measured using linear incident polarization are more directly interpreted in terms of longitudinal and transverse moments than are the same signals measured using elliptical polarization. Varying photon energy near the Fe L3line is shown to be an effective means of resolving distinctly different reversal behavior at the top and bottom of the 20 nm thick Fe layer resulting from the strong exchange coupling at the Sin-Co/Fe interface. Measured x-ray MOKE spectra and signals are in qualitative agreement with those calculated using standard magneto-optical formalisms incorporating interference between different layers and measured helicity-dependent magneto-optical constants for Fe.
Effects of high light intensities on the optical Kerr nonlinearity of semiconducting polymers
International Nuclear Information System (INIS)
Charra, Fabrice
1990-01-01
Experimental investigations, in the picosecond time scale, of the Kerr type optical nonlinearity (or pump and probe) are presented. The nonlinear molecules semiconducting polymers of the type poly-diacetylene. The degenerate case (pump and probe at the same frequency) has been studied by four wave mixing at 1064 nm, in the configuration of phase conjugation. It is shown that the response is dominated by high orders of nonlinearity. The results are analysed in terms of two photon resonance. The non-degenerate case is studied by two wave mixing or in the optical Kerr gate experiment. The optical Stark effect and the differential spectra of photoinduced species are analysed. Two photon excitations at 1064 nm and one photon excitations at 532 nm are compared. A consequence of the mechanism of the nonlinearity is the possibility of generating phase conjugate waves at double frequency. The theoretical analysis and the experimental demonstration of this process are presented. The experiment is only sensitive to nonlinearities of the fifth order or more and thus allows to clarify its origins and dynamics. Finally, quantum modelling and calculations of the nonlinear optical responses, developed for the interpretations of the above experiments, are presented. (author) [fr
A note on physical mass and the thermodynamics of AdS-Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
McInnes, Brett [Department of Mathematics, National University of Singapore, 10, Lower Kent Ridge Road, 119076 (Singapore); Ong, Yen Chin, E-mail: matmcinn@nus.edu.sg, E-mail: yenchin.ong@nordita.org [Nordic Institute for Theoretical Physics, KTH Royal Institute of Technology Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden)
2015-11-01
As with any black hole, asymptotically anti-de Sitter Kerr black holes are described by a small number of parameters, including a ''mass parameter'' M that reduces to the AdS-Schwarzschild mass in the limit of vanishing angular momentum. In sharp contrast to the asymptotically flat case, the horizon area of such a black hole increases with the angular momentum parameter a if one fixes M; this appears to mean that the Penrose process in this case would violate the Second Law of black hole thermodynamics. We show that the correct procedure is to fix not M but rather the ''physical'' mass E=M/(1−a{sup 2}/L{sup 2}){sup 2}; this is motivated by the First Law. For then the horizon area decreases with a. We recommend that E always be used as the mass in physical processes: for example, in attempts to ''over-spin'' AdS-Kerr black holes.
Spectroscopy of Kerr Black Holes with Earth- and Space-Based Interferometers.
Berti, Emanuele; Sesana, Alberto; Barausse, Enrico; Cardoso, Vitor; Belczynski, Krzysztof
2016-09-02
We estimate the potential of present and future interferometric gravitational-wave detectors to test the Kerr nature of black holes through "gravitational spectroscopy," i.e., the measurement of multiple quasinormal mode frequencies from the remnant of a black hole merger. Using population synthesis models of the formation and evolution of stellar-mass black hole binaries, we find that Voyager-class interferometers will be necessary to perform these tests. Gravitational spectroscopy in the local Universe may become routine with the Einstein Telescope, but a 40-km facility like Cosmic Explorer is necessary to go beyond z∼3. In contrast, detectors like eLISA (evolved Laser Interferometer Space Antenna) should carry out a few-or even hundreds-of these tests every year, depending on uncertainties in massive black hole formation models. Many space-based spectroscopical measurements will occur at high redshift, testing the strong gravity dynamics of Kerr black holes in domains where cosmological corrections to general relativity (if they occur in nature) must be significant.
2010-04-01
... produce dental materials such as dental prosthetics, dental composites, dental impressions, dental... materials such as dental prosthetics, dental composites, dental impressions, dental adhesives, and other... Technologies, a Wholly-Owned Subsidiary of Kerr Dental/Sybron Dental Specialities, Formally Known as Customedix...
International Nuclear Information System (INIS)
Shin, S.
1991-01-01
Multilayer thin films of Tb and FeCo were prepared by sequential thermal evaporation of Tb and Fe 90 Co 10 alloy on glass substrates at ambient temperature in a vacuum of about 1 x 10 -6 Torr. The repeat distance of the films was varied from 3.5 to 175 A while maintaining the composition constant for all samples. Low-angle x-ray diffraction and Auger electron spectroscopy showed that a multilayer structure was achieved for films fabricated with a repeat distance Λ≥31.5 A. The polar Kerr rotation angle and coercivity of the samples were obtained by measuring the polar Kerr hysteresis loop using a 632.8-nm HeNe laser. It was observed that for the samples having a multilayer structure, the remnant Kerr angle and coercivity monotonically decreased with increasing repeat distance, and eventually disappeared for Λ≥70 A. For the samples showing a nonmultilayer structure, the remnant Kerr angle was independent of repeat distance. However, the coercivity increased with repeat distance until a broad maximum was obtained around Λ congruent 14--21 A
Hawking radiation as tunneling from the event horizon of NUT-Kerr-Newman de Sitter black hole
International Nuclear Information System (INIS)
Hui-Ling, Li; Shu-Shenh, Yang; Qing-Quan, Jiang; De-Jiang, Qi
2005-01-01
Adopting the method of quantum radiation as tunneling, Hawking radiation as tunneling from the event horizon of NUT-Kerr-Newman de Sitter black hole is studied. The result indicates that the tunneling rate of the particle on the event horizon is related to the change of Bekenstein-Hawking entropy and the real spectrum is not strictly thermal at all
The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror
Hod, Shahar
2016-10-01
The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over the last four decades. Previous numerical studies of this spinning black-hole bomb have revealed the interesting fact that the superradiant instability shuts down if the reflecting mirror is placed too close to the black-hole horizon. In the present study we use analytical techniques to explore the superradiant instability regime of this composed Kerr-black-hole-linearized-scalar-field-mirror system. In particular, it is proved that the lower bound rm/r+ >1/2 (√{ 1 +8M/r- } - 1) provides a necessary condition for the development of the exponentially growing superradiant instabilities in this composed physical system, where rm is the radius of the confining mirror and r± are the horizon radii of the spinning Kerr black hole. We further show that, in the linearized regime, this analytically derived lower bound on the radius of the confining mirror agrees with direct numerical computations of the superradiant instability spectrum which characterizes the spinning black-hole-mirror bomb.
Czech Academy of Sciences Publication Activity Database
Životský, O.; Hendrych, A.; Klimša, L.; Jirásková, Yvonna; Buršík, Jiří; Gomez, J.A.M.; Janičkovič, D.
2012-01-01
Roč. 324, č. 4 (2012), s. 569-577 ISSN 0304-8853 Institutional research plan: CEZ:AV0Z20410507 Keywords : Surface magnetism * Magnetooptic Kerr effect * Magneto-optical microscopy * ILEEMS * CEMS * Nanoscale phase separation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.826, year: 2012
Half-metallicity and giant magneto-optical Kerr effect in N-doped NaTaO3
Saeed, Yasir; Singh, Nirpendra; Schwingenschlö gl, Udo
2012-01-01
gradient approximation. We find a giant polar Kerr rotation of 2.16°at 725 nm wave length (visible region), much higher than in other half-metallic perovskites and the prototypical half-metal PtMnSb. We explain the physical origin of this unexpected
Chantry, L.; Cayatte, V.; Sauty, C.; Vlahakis, N.; Tsinganos, K.
2018-04-01
Context. High-resolution radio imaging of active galactic nuclei (AGN) has revealed that the jets of some sources present superluminal knots and transverse stratification. Recent observational projects, such as ALMA and γ-ray telescopes, such as HESS and HESS2 have provided new observational constraints on the central regions of rotating black holes in AGN, suggesting that there is an inner- or spine-jet surrounded by a disk wind. This relativistic spine-jet is likely to be composed of electron-positron pairs extracting energy from the black hole and will be explored by the future γ-ray telescope CTA. Aims: In this article we present an extension to and generalization of relativistic jets in Kerr metric of the Newtonian meridional self-similar mechanism. We aim at modeling the inner spine-jet of AGN as a relativistic light outflow emerging from a spherical corona surrounding a Kerr black hole and its inner accretion disk. Methods: The model is built by expanding the metric and the forces with colatitude to first order in the magnetic flux function. As a result of the expansion, all colatitudinal variations of the physical quantities are quantified by a unique parameter. Unlike previous models, effects of the light cylinder are not neglected. Results: Solutions with high Lorentz factors are obtained and provide spine-jet models up to the polar axis. As in previous publications, we calculate the magnetic collimation efficiency parameter, which measures the variation of the available energy across the field lines. This collimation efficiency is an integral part of the model, generalizing the classical magnetic rotator efficiency criterion to Kerr metric. We study the variation of the magnetic efficiency and acceleration with the spin of the black hole and show their high sensitivity to this integral. Conclusions: These new solutions model collimated or radial, relativistic or ultra-relativistic outflows in AGN or γ-ray bursts. In particular, we discuss the
Carmona-Fonseca, Jaime
2003-11-01
To establish reference values for erythrocyte cholinesterase (EC 3.1.1.7) activity for the active working population of two regions of the department of Antioquia, Colombia, that are located at different altitudes above sea level. We took representative samples from populations of active working persons 18 to 59 years old from two regions in the department of Antioquia: (1) the Aburrá Valley (1 540 m above sea level) and (2) the near east of the department (2 150 m above sea level). We excluded workers who were using cholinesterase-inhibiting substances in their work or at home, those who had a disease that altered their cholinesterase levels, and those who said they were not in good health. We measured the erythrocyte cholinesterase activity using two methods: (1) the Michel method and (2) the EQM method (EQM Research, Cincinnati, Ohio, United States of America). We carried out the measurements with 827 people, 415 from the Aburrá Valley and 412 from the near east region. We compared proportions using the chi-square test and Fisher's exact test. We utilized the Student's t test for independent samples to compare two averages. To simultaneously compare three or more averages, analysis of variance was used, followed by the Newman-Keuls multiple-range test. When the variables were not normally distributed or when the variances were not homogeneous, Kruskal-Wallis nonparametric analysis of variance was used to compare the medians. Three computer software programs were used in the statistical analysis: SPSS 9.0, SGPlus 7.1, and Epi Info 6.04. In all the statistical tests the level of significance was set at P EQM method was 35.21 U/g hemoglobin (95% CI: 34.82 to 35.60). With the Michel method: (1) the enzymatic activity differed significantly between the two regions, according to the Newman-Keuls test; (2) within each region, the enzymatic activity was significantly higher among males than among females, according to the Newman-Keuls test; and (3) in none of the
Directory of Open Access Journals (Sweden)
Cinthya Regina Ribeiro
2013-01-01
Full Text Available El presente trabajo busca problematizar la supuesta constitución virtuosa entre educación y conocimiento, oriunda de cierta herencia cultural de la modernidad occidental. La problemática se apoya en la indagación difusa, aunque insistente, que se repite en el campo de la educación: “¿De qué se trata el acto de pensar, en educación, en la contemporaneidad?”. El tomar las condiciones actuales de pensamiento como un problema de investigación en educación, pone en duda la histórica articulación entre conocimiento y pensamiento reflexivo, lo que obliga a la confrontación de ciertas mezclas pedagógicas preciadas en el campo educativo moderno. Tal enfrentamiento se realiza a la luz de las reflexiones de los pensadores Michel Foucault y Friedrich Nietzsche, dada la relevancia estratégica de sus producciones, especialmente sobre el lenguaje, la producción de verdad y sus implicaciones en los modos de conocer y pensar. Se busca construir una crítica del lenguaje en dirección a una crítica del pensamiento en educación, en el centro de una problematización ético-política. En este trabajo, tal plataforma analítica se configura a partir de las discusiones de Michel Foucault, tanto en relación a la cuestión del pensamiento del afuera, como en relación al pensamiento de la diferencia, tal como fue formulado por Gilles Deleuze. Sugerimos que la explotación de ese debate, puede actuar como un ejercicio de exterioridad o de pensamiento diferencial en el juego con el conocimiento y con el pensamiento reflexivo presentes en el campo de la educación, sea en el ámbito de las tareas pedagógicas cotidianas en la escuela, o en el campo de la producción de la investigación en la educación.
Directory of Open Access Journals (Sweden)
Wolfgang Neurath
2016-12-01
Full Text Available Dieser Beitrag rekapituliert im Blick auf die Überlappungen von Macht, Souveränität und Herrschaft die soziale Morphologie der Foucaultschen Gesellschaftstheorie und betont dabei die Aktualität von Forschungen, die sich machtkritisch an den Dispositivbegriff anlehnen. Was ein Dispositiv ist, wird im Rekurs auf Deleuze und Agamben vor Augen geführt, um in der Figur der "schizophrenen Flucht" ein entscheidendes Moment der französischen Debatten auszumachen. Dabei ist der Panoptismus nach wie vor ein bemerkenswertes Modell, um historisch die innere Funktionsweise von Disziplinargesellschaften zu begreifen, die sich zu Kontrollgesellschaften gewandelt haben. Dem Homo digitalis steht angesichts von Big Data im Semiokapitalismus des 21. Jahrhunderts ein System wechselseitiger Kontrolle vor Augen, dem er sich lückenlos unterwerfen soll. Dem setzt sich nach wie vor die Figur der widerständigen Subjektivierung entgegen, wie sie Foucault in seinem Spätwerk entworfen hat. Auf allgemeinster Ebene hebt dieser Artikel hervor, dass wir auch heute noch ein politisches Modell vor Augen haben, dass der antiken Arena im Sinne einer politischen Heterotopie entspricht, in der es im Krieg um das nackte Überleben geht. Zusammenfassend wird Foucaults Kriegsparadigma über Michel de Certeaus Modellierung von Strategie und Taktik auf die Figur des Bürgerkriegs bezogen, um insgesamt zu betonen, dass dort wo Macht ist, immer auch Widerstand möglich ist. This article recaps the social morphology of Foucault’s theory of society in the light of power, sovereignty, and domination, emphasizing the actuality of research that is referring to the concept of apparatus. This concept is pointed out in the recourse to Deleuze and Agamben, to identify – in the figure of "schizophrenic escape" – a decisive moment in the French debates. Panoptism is still a remarkable model for historical understanding of the internal functioning of disciplinary societies that have
Directory of Open Access Journals (Sweden)
Fernando de Almeida Silveira
2008-12-01
Full Text Available Michel Foucault investiga "a história das relações que o pensamento mantém com a verdade" e como se estabelece a correlação entre pensamento e verdade, tendo o enunciado do corpo como elemento discursivo fundamental na constituição dos jogos de verdades sobre o sujeito moderno. Através da leitura da bibliografia desse autor, de comentaristas e de outros filósofos modernos, esta pesquisa estuda a questão do corpo na fase arqueológica foucaultiana, principalmente no livro As Palavras e As Coisas, destacando as formações discursivas do corpo, da vida e do homem em seus efeitos subjetivadores, com especial referência à constituição discursiva do sujeito psicológico. Verificou-se que Foucault desnaturaliza o corpo, apresentando-o como conceito-chave (ou grade de especificação na produção de discursos sobre o homem moderno, o que nos permite também compreender a psiqué não como emanação ou essência metafísica do corpo, mas como instrumento discursivo, singularmente emergente na história do pensamento moderno.Michel Foucault investiga "la historia de las relaciones que el pensamiento mantiene con la verdad" y como la correlación entre el pensamiento y la verdad es establecida, al traer el cuerpo como elemento discursivo fundamental en los juegos de verdades sobre la constitución del sujeto moderno. A través de la lectura de la bibliografía de este autor, comentaristas y otros filósofos, la investigación estudia la cuestión del cuerpo en la fase de Foucault arqueológica, principalmente en "Las Palabras y las Cosas", destacando las formaciones discursivas del cuerpo, de la vida y del hombre en sus efectos sujetivadores, a la constitución del sujeto psicológico. Se comprobó que Foucault desnaturaliza el cuerpo, presentándolo como concepto-clave en la producción de discursos sobre el hombre moderno. Lo que nos permite comprender también la psiqué, no como emanación o esencia metafísica del cuerpo, sino como
International Nuclear Information System (INIS)
Zhang Zaiyun; Liu Zhenhai; Miao Xiujin; Chen Yuezhong
2011-01-01
In this Letter, we investigate the perturbed nonlinear Schroedinger's equation (NLSE) with Kerr law nonlinearity. All explicit expressions of the bounded traveling wave solutions for the equation are obtained by using the bifurcation method and qualitative theory of dynamical systems. These solutions contain bell-shaped solitary wave solutions, kink-shaped solitary wave solutions and Jacobi elliptic function periodic solutions. Moreover, we point out the region which these periodic wave solutions lie in. We present the relation between the bounded traveling wave solution and the energy level h. We find that these periodic wave solutions tend to the corresponding solitary wave solutions as h increases or decreases. Finally, for some special selections of the energy level h, it is shown that the exact periodic solutions evolute into solitary wave solution.
Mach-Zehnder interferometer implementation for thermo-optical and Kerr effect study
Bundulis, Arturs; Nitiss, Edgars; Busenbergs, Janis; Rutkis, Martins
2018-04-01
In this paper, we propose the Mach-Zehnder interferometric method for third-order nonlinear optical and thermo-optical studies. Both effects manifest themselves as refractive index dependence on the incident light intensity and are widely employed for multiple opto-optical and thermo-optical applications. With the implemented method, we have measured the Kerr and thermo-optical coefficients of chloroform under CW, ns and ps laser irradiance. The application of lasers with different light wavelengths, pulse duration and energy allowed us to distinguish the processes responsible for refractive index changes in the investigated solution. Presented setup was also used for demonstration of opto-optical switching. Results from Mach-Zehnder experiment were compared to Z-scan data obtained in our previous studies. Based on this, a quality comparison of both methods was assessed and advantages and disadvantages of each method were analyzed.
Observing the contour profile of a Kerr-Sen black hole
Lan, X. G.; Pu, J.
2018-06-01
In this paper, the shadow and the corresponding naked singularity cast by a Kerr-Sen black hole are studied. It is found that the shadow of a rotating black hole would be a dark zone surrounded by a deformed circle, and the shadow is distorted more away from a circle when the black hole approaches the extremal case. Besides, it is shown that the mean radius of the shadow decreases and distortion parameter increases with the increasing of charge, respectively. However, the mean radius and the distortion parameter vary complicatedly with the change of spin parameter. In the beginning, both observables decrease rapidly with the increasing of specific angular momentum, nevertheless, they increase slightly in the latter part. These results show that there would be a significant effect of the spin on the shadows, which would be of great importance for probing the nature of the black hole.
Berry phase in a two-atom Jaynes-Cummings model with Kerr medium
International Nuclear Information System (INIS)
Bu Shenping; Zhang Guofeng; Liu Jia; Chen Ziyu
2008-01-01
The Jaynes-Cummings model (JCM) is an very important model for describing interaction between quantized electromagnetic fields and atoms in cavity quantum electrodynamics (QED). This model is generalized in many different directions since it predicts many novel quantum effects that can be verified by modern physics experimental technologies. In this paper, the Berry phase and entropy of the ground state for arbitrary photon number n of a two-atom Jaynes-Cummings model with Kerr-like medium are investigated. It is found that there is some correspondence between their images, especially the existence of a curve in the Δ-ε plane along which the energy, Berry phase and entropy all reach their special values. So it is available for detecting entanglement by applying Berry phase.
Berry phase in a two-atom Jaynes-Cummings model with Kerr medium
Energy Technology Data Exchange (ETDEWEB)
Bu Shenping; Zhang Guofeng; Liu Jia; Chen Ziyu [Department of Physics, School of Science, BeiHang University, Xueyuan Road, Beijing 100083 (China)], E-mail: chenzy@buaa.edu.cn
2008-12-15
The Jaynes-Cummings model (JCM) is an very important model for describing interaction between quantized electromagnetic fields and atoms in cavity quantum electrodynamics (QED). This model is generalized in many different directions since it predicts many novel quantum effects that can be verified by modern physics experimental technologies. In this paper, the Berry phase and entropy of the ground state for arbitrary photon number n of a two-atom Jaynes-Cummings model with Kerr-like medium are investigated. It is found that there is some correspondence between their images, especially the existence of a curve in the {delta}-{epsilon} plane along which the energy, Berry phase and entropy all reach their special values. So it is available for detecting entanglement by applying Berry phase.
Ivanov, Yurii P.
2014-02-14
The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.
Energy Technology Data Exchange (ETDEWEB)
Cárdenas-Avendaño, Alejandro [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Jiang, Jiachen [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Bambi, Cosimo, E-mail: bambi@fudan.edu.cn [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Theoretical Astrophysics, Eberhard-Karls Universität Tübingen, 72076 Tübingen (Germany)
2016-09-10
The recent announcement of the detection of gravitational waves by the LIGO/Virgo Collaboration has opened a new window to test the nature of astrophysical black holes. Konoplya & Zhidenko have shown how the LIGO data of GW 150914 can constrain possible deviations from the Kerr metric. In this letter, we compare their constraints with those that can be obtained from accreting black holes by fitting their X-ray reflection spectrum, the so-called iron line method. We simulate observations with eXTP, a next generation X-ray mission, finding constraints much stronger than those obtained by Konoplya & Zhidenko. Our results can at least show that, contrary to what is quite commonly believed, it is not obvious that gravitational waves are the most powerful approach to test strong gravity. In the presence of high quality data and with the systematics under control, the iron line method may provide competitive constraints.
Thermal Casimir effect in Kerr spacetime with quintessence and massive gravitons
Energy Technology Data Exchange (ETDEWEB)
Bezerra, V.B. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil); Christiansen, H.R. [Ciencia e Tecnologia do Ceara (IFCE), Departamento de Fisica, Instituto Federal de Educacao, Sobral, CE (Brazil); Cunha, M.S. [Universidade Estadual do Ceara, Grupo de Fisica Teorica (GFT), Fortaleza, CE (Brazil); Muniz, C.R.; Tahim, M.O. [Universidade Estadual do Ceara, Faculdade de Educacao, Ciencias e Letras do Sertao Central, Quixada, CE (Brazil)
2017-11-15
Starting from an analytical expression for the Helmholtz free energy we calculate the thermal corrections to the Casimir energy density and entropy within nearby ideal parallel plates in the vacuum of a massless scalar field. Our framework is the Kerr spacetime in the presence of quintessence and massive gravitons. The high and low temperature regimes are especially analyzed in order to distinguish the main contributions. For instance, in the high temperature regime, we show that the force between the plates is repulsive and grows with both the quintessence and the massive gravitons. Regarding the Casimir entropy, our results are in agreement with the Nernst heat theorem and therefore confirm the third law of thermodynamics in the present scenario. (orig.)
Control of Wave Propagation and Effect of Kerr Nonlinearity on Group Index
International Nuclear Information System (INIS)
Hazrat, Ali; Iftikhar, Ahmed; Ziauddin
2013-01-01
We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2006) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Barlow, Nathaniel S.; Weinstein, Steven J.; Faber, Joshua A.
2017-07-01
An accurate closed-form expression is provided to predict the bending angle of light as a function of impact parameter for equatorial orbits around Kerr black holes of arbitrary spin. This expression is constructed by assuring that the weak- and strong-deflection limits are explicitly satisfied while maintaining accuracy at intermediate values of impact parameter via the method of asymptotic approximants (Barlow et al 2017 Q. J. Mech. Appl. Math. 70 21-48). To this end, the strong deflection limit for a prograde orbit around an extremal black hole is examined, and the full non-vanishing asymptotic behavior is determined. The derived approximant may be an attractive alternative to computationally expensive elliptical integrals used in black hole simulations.
International Nuclear Information System (INIS)
Barlow, Nathaniel S; Faber, Joshua A; Weinstein, Steven J
2017-01-01
An accurate closed-form expression is provided to predict the bending angle of light as a function of impact parameter for equatorial orbits around Kerr black holes of arbitrary spin. This expression is constructed by assuring that the weak- and strong-deflection limits are explicitly satisfied while maintaining accuracy at intermediate values of impact parameter via the method of asymptotic approximants (Barlow et al 2017 Q. J. Mech. Appl. Math . 70 21–48). To this end, the strong deflection limit for a prograde orbit around an extremal black hole is examined, and the full non-vanishing asymptotic behavior is determined. The derived approximant may be an attractive alternative to computationally expensive elliptical integrals used in black hole simulations. (paper)
Directory of Open Access Journals (Sweden)
Rostaman Rostaman
2016-12-01
Full Text Available Lac insects (Laccifer lacca Kerr live parasitically on “kosambi” plants, and produce resins that are called lac. Lac are used for electronics, printing, textile, clothing, cosmetics, and food industry. The insects also live on various plants. The goal of this research was to evaluate the population quality of Lac insect that live on three host plants. The best parameter for population quality was biomass or lac production. Three host plants were inoculated by broods. The result showed that “kosambi” was the best host plant for the insect due to higher biomass (i.e lac production than “kabesak putih” and “kabesak hitam” plants.
Korteweg-de Vries description of Helmholtz-Kerr dark solitons
Energy Technology Data Exchange (ETDEWEB)
Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom) ; McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom) ; Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)
2006-12-15
A wide variety of different physical systems can be described by a relatively small set of universal equations. For example, small-amplitude nonlinear Schroedinger dark solitons can be described by a Korteweg-de Vries (KdV) equation. Reductive perturbation theory, based on linear boosts and Gallilean transformations, is often employed to establish connections to and between such universal equations. Here, a novel analytical approach reveals that the evolution of small-amplitude Helmholtz-Kerr dark solitons is also governed by a KdV equation. This broadens the class of nonlinear systems that are known to possess KdV soliton solutions, and provides a framework for perturbative analyses when propagation angles are not negligibly small. The derivation of this KdV equation involves an element that appears new to weakly nonlinear analyses, since transformations are required to preserve the rotational symmetry inherent to Helmholtz-type equations.
APPLIED OPTICS. Overcoming Kerr-induced capacity limit in optical fiber transmission.
Temprana, E; Myslivets, E; Kuo, B P-P; Liu, L; Ataie, V; Alic, N; Radic, S
2015-06-26
Nonlinear optical response of silica imposes a fundamental limit on the information transfer capacity in optical fibers. Communication beyond this limit requires higher signal power and suppression of nonlinear distortions to prevent irreversible information loss. The nonlinear interaction in silica is a deterministic phenomenon that can, in principle, be completely reversed. However, attempts to remove the effects of nonlinear propagation have led to only modest improvements, and the precise physical mechanism preventing nonlinear cancellation remains unknown. We demonstrate that optical carrier stability plays a critical role in canceling Kerr-induced distortions and that nonlinear wave interaction in silica can be substantially reverted if optical carriers possess a sufficient degree of mutual coherence. These measurements indicate that fiber information capacity can be notably increased over previous estimates. Copyright © 2015, American Association for the Advancement of Science.
Spin Interaction under the Collision of Two Kerr-(Anti-de Sitter Black Holes
Directory of Open Access Journals (Sweden)
Bogeun Gwak
2017-12-01
Full Text Available We investigate herein the spin interaction during collisions between Kerr-(anti-de Sitter black holes. The spin interaction potential depends on the relative rotation directions of the black holes, and this potential can be released as gravitational radiation upon collision. The energy of the radiation depends on the cosmological constant and corresponds to the spin interaction potential in the limit that one of the black holes has negligibly small mass and angular momentum. We then determine the approximate overall behaviors of the upper bounds on the radiation using thermodynamics. The results indicate that the spin interaction can consistently contribute to the radiation. In addition, the radiation depends on the stability of the black hole produced by the collision.
Holiday, L. F.; Gibson, U. J.
2006-12-01
We report on the use of dielectric coatings to improve the contrast of longitudinal magneto-optic Kerr effect signals from submicron magnetic structures. Electron-beam lithography was used to define disks in 22 nm thick Ni films deposited on Si substrates. The structures were measured in four configurations: as-deposited, through a fused silica prism using index-matching fluid, coated with ZnS, and using a prism on top of the ZnS layer. The modified samples show up to 20 times improvement in the MOKE contrast due to admittance matching to the magnetic material and suppression of the substrate reflectance. The behavior is successfully predicted by a model that includes the magneto-optic response of the nickel layer and accounts for the fraction of the beam intercepted by the magnetic structure.
Waveguide-Plasmon Polaritons Enhance Transverse Magneto-Optical Kerr Effect
Directory of Open Access Journals (Sweden)
Lars E. Kreilkamp
2013-11-01
Full Text Available Magneto-optical effects in ferrimagnetic or ferromagnetic materials are usually too weak for potential applications. The transverse magneto-optical Kerr effect (TMOKE in ferromagnetic films is typically on the order of 0.1%. Here, we demonstrate experimentally the enhancement of TMOKE due to the interaction of particle plasmons in gold nanowires with a photonic waveguide consisting of magneto-optical material, where hybrid waveguide-plasmon polaritons are excited. We achieve a large TMOKE that modulates the transmitted light intensity by 1.5%, accompanied by high transparency of the system. Our concept may lead to novel devices of miniaturized photonic circuits and switches, which are controllable by an external magnetic field.
Energy Technology Data Exchange (ETDEWEB)
El-Menoufi, Basem Kamal [Department of Physics, University of Massachusetts,Amherst, MA 01003 (United States)
2016-05-05
In the context of effective field theory, we consider quantum gravity with minimally coupled massless particles. Fixing the background geometry to be of the Kerr-Schild type, we fully determine the one-loop effective action of the theory whose finite non-local part is induced by the long-distance portion of quantum loops. This is accomplished using the non-local expansion of the heat kernel in addition to a non-linear completion technique through which the effective action is expanded in gravitational curvatures. Via Euclidean methods, we identify a logarithmic correction to the Bekenstein-Hawking entropy of Schwarzschild black hole. Using dimensional transmutation the result is shown to exhibit an interesting interplay between the UV and IR properties of quantum gravity.
Energy Technology Data Exchange (ETDEWEB)
Zahn, Patrick; Bayer, Jonas [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart (Germany); Institute for Innovative Surfaces FINO, Aalen University, Beethovenstrasse 1, 73430 Aalen (Germany); Stahl, Claudia; Ruoss, Stephen; Graefe, Joachim; Schuetz, Gisela [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart (Germany); Albrecht, Joachim [Institute for Innovative Surfaces FINO, Aalen University, Beethovenstrasse 1, 73430 Aalen (Germany)
2016-07-01
With XMCD microscopy it is possible to visualize the critical current density of the superconductor YBCO with high spatial resolution. Therefore, soft magnetic CoFeB is introduced as sensor layer. The magnetic stray fields of the supercurrents lead to a local reorientation of the magnetic moments in the ferromagnet, which are then imaged via X-ray microscopy. These experiments have to be carried out at the scanning X-ray microscope MAXYMUS at the synchrotron Bessy II in Berlin. For that purpose pre-characterization of the sensor is highly desirable: Magnetic interactions between the superconductor and the ferromagnetic sensor layer have been investigated at low temperatures using Kerr-effect measurements. Therefore hysteresis loops are obtained by a sophisticated magnet and field ramping setup within the NanoMOKE3 system. The results are used to optimize the ferromagnetic sensor layer for XMCD microscopy of superconductors.
The Kerr/fluid duality and the singularity of solutions to the fluid equation
International Nuclear Information System (INIS)
Fujisawa, Ippei; Nakayama, Ryuichi
2016-01-01
An equation for a viscous incompressible fluid on a spheroidal surface that is dual to the perturbation around the near-near-horizon extreme Kerr (near-NHEK) black hole is derived. It is also shown that an expansion scalar θ of a congruence of null geodesics on the perturbed horizon of the perturbed near-NHEK spacetime, which is dual to a viscous incompressible fluid, is not in general positive semidefinite, even if initial conditions on the velocity are smooth. Unless the initial conditions are appropriately adjusted, caustics of null congruence will occur on the perturbed horizon in the future. A similar result is obtained for a perturbed Schwarzschild black hole spacetime, which is dual to a viscous incompressible fluid on S 2 . An initial condition that θ be positive semidefinite at any point on S 2 is a necessary condition for the existence of smooth solutions to the incompressible Navier-Stokes equation on S 2
Ivanov, Yurii P.; del Real, R. P.; Chubykalo-Fesenko, O.; Vá zquez, M.
2014-01-01
The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.
Korteweg-de Vries description of Helmholtz-Kerr dark solitons
International Nuclear Information System (INIS)
Christian, J M; McDonald, G S; Chamorro-Posada, P
2006-01-01
A wide variety of different physical systems can be described by a relatively small set of universal equations. For example, small-amplitude nonlinear Schroedinger dark solitons can be described by a Korteweg-de Vries (KdV) equation. Reductive perturbation theory, based on linear boosts and Gallilean transformations, is often employed to establish connections to and between such universal equations. Here, a novel analytical approach reveals that the evolution of small-amplitude Helmholtz-Kerr dark solitons is also governed by a KdV equation. This broadens the class of nonlinear systems that are known to possess KdV soliton solutions, and provides a framework for perturbative analyses when propagation angles are not negligibly small. The derivation of this KdV equation involves an element that appears new to weakly nonlinear analyses, since transformations are required to preserve the rotational symmetry inherent to Helmholtz-type equations
Mössbauer and Kerr microscopy investigation of crystallization in FeCoB ribbons
Energy Technology Data Exchange (ETDEWEB)
Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com, E-mail: vrreddy@csr.res.in; Hussain, Zaineb; Babu, Hari [UGC DAE Consortium for Scientific Research, University Campus, Kandhwa Road, Indore-452001 India (India); Shrivastava, Namrata [School of Physics, DAVV, Khandwa Road, Indore – 452001 India (India); Gupta, Ajay [Amity Centre for Spintronic Materials, Amity University, Noida 201303.India (India)
2016-05-23
The present work reports the crystallization study of amorphous FeCoB ribbons using x-ray diffraction, {sup 57}Fe Mössbauer spectroscopy in transmission mode and magneto-optical Kerr (MOKE) microscopy. Annealing at 673 K is found to result in crystallization. From the Mossbauer measurements it is observed that the Fe magnetic moments are in the plane of sample for as-cast ribbon; α-FeCo, (Fe{sub 0.5}Co{sub 0.5}){sub 2}B and Fe{sub 2}B phases are formed after crystallization. MOKE microscopy revealed that wide 180° domain walls & narrow fingerprint domains are observed before crystallization and fine domains are observed after crystallization. The results are explained in terms of the presence of internal stresses and their annealing with thermal heat treatment.
Spectral features of radiation from Nordstroem and Kerr-Newman white holes. [Kinetics
Energy Technology Data Exchange (ETDEWEB)
Dadhich, N [Poona Univ. (India). Dept. of Mathematics and Statistics
1977-01-01
Unlike the Schwarzschild white hole, Nordstroem and Kerr-Newman white holes cannot explode right down from the space time singularity R = 0. For example a charged white hole has to commence explosion (i.e., comes into existence) with a radius Rsub(o)=Rsub(c)(2-Rsub(c)/Rsub(b))sup(-1) where Rsub(c) is the 'classical radius' and Rsub(b) is the final radius attained when the stationary state is reached. That means charged and rotating black holes also cannot hit the singularity R = 0 and perish. Here the explosion is decelerated by the presence of charge and rotation and hence the radiation emitted would be not as energetic as in the Schwarzschild case where its energy is infinitely large for emission from R = 0.
Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator.
Wu, Liang; Salehi, M; Koirala, N; Moon, J; Oh, S; Armitage, N P
2016-12-02
Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi 2 Se 3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry's phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system. Copyright © 2016, American Association for the Advancement of Science.
Proto-jet configurations in RADs orbiting a Kerr SMBH: symmetries and limiting surfaces
Pugliese, D.; Stuchlík, Z.
2018-05-01
Ringed accretion disks (RADs) are agglomerations of perfect-fluid tori orbiting around a single central attractor that could arise during complex matter inflows in active galactic nuclei. We focus our analysis to axi-symmetric accretion tori orbiting in the equatorial plane of a supermassive Kerr black hole; equilibrium configurations, possible instabilities, and evolutionary sequences of RADs were discussed in our previous works. In the present work we discuss special instabilities related to open equipotential surfaces governing the material funnels emerging at various regions of the RADs, being located between two or more individual toroidal configurations of the agglomerate. These open structures could be associated to proto-jets. Boundary limiting surfaces are highlighted, connecting the emergency of the jet-like instabilities with the black hole dimensionless spin. These instabilities are observationally significant for active galactic nuclei, being related to outflows of matter in jets emerging from more than one torus of RADs orbiting around supermassive black holes.
Time-resolved scanning Kerr microscopy of flux beam formation in hard disk write heads
International Nuclear Information System (INIS)
Valkass, Robert A. J.; Spicer, Timothy M.; Burgos Parra, Erick; Hicken, Robert J.; Bashir, Muhammad A.; Gubbins, Mark A.; Czoschke, Peter J.; Lopusnik, Radek
2016-01-01
To meet growing data storage needs, the density of data stored on hard disk drives must increase. In pursuit of this aim, the magnetodynamics of the hard disk write head must be characterized and understood, particularly the process of “flux beaming.” In this study, seven different configurations of perpendicular magnetic recording (PMR) write heads were imaged using time-resolved scanning Kerr microscopy, revealing their detailed dynamic magnetic state during the write process. It was found that the precise position and number of driving coils can significantly alter the formation of flux beams during the write process. These results are applicable to the design and understanding of current PMR and next-generation heat-assisted magnetic recording devices, as well as being relevant to other magnetic devices.
Onset of superradiant instabilities in the composed Kerr-black-hole–mirror bomb
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emeq Hefer 40250 (Israel); The Hadassah Institute, Jerusalem 91010 (Israel)
2014-09-07
It was first pointed out by Press and Teukolsky that a system composed of a spinning Kerr black hole surrounded by a reflecting mirror may develop instabilities. The physical mechanism responsible for the development of these exponentially growing instabilities is the superradiant amplification of bosonic fields confined between the black hole and the mirror. A remarkable feature of this composed black-hole–mirror-field system is the existence of a critical mirror radius, r{sub m}{sup stat}, which supports stationary (marginally-stable) field configurations. This critical (‘stationary’) mirror radius marks the boundary between stable and unstable black-hole–mirror-field configurations: composed systems whose confining mirror is situated in the region r{sub m}
Numerical study of the quasinormal mode excitation of Kerr black holes
International Nuclear Information System (INIS)
Dorband, Ernst Nils; Diener, Peter; Tiglio, Manuel; Berti, Emanuele; Schnetter, Erik
2006-01-01
We present numerical results from three-dimensional evolutions of scalar perturbations of Kerr black holes. Our simulations make use of a high-order accurate multiblock code which naturally allows for adapted grids and smooth inner (excision) and outer boundaries. We focus on the quasinormal ringing phase, presenting a systematic method for extraction of the quasinormal mode frequencies and amplitudes and comparing our results against perturbation theory. The detection of a single mode in a ringdown waveform allows for a measurement of the mass and spin of a black hole; a multimode detection would allow a test of the Kerr nature of the source. Since the possibility of a multimode detection depends on the relative mode amplitude, we study this topic in some detail. The amplitude of each mode depends exponentially on the starting time of the quasinormal regime, which is not defined unambiguously. We show that this time-shift problem can be circumvented by looking at appropriately chosen relative mode amplitudes. From our simulations we extract the quasinormal frequencies and the relative and absolute amplitudes of corotating and counterrotating modes (including overtones in the corotating case). We study the dependence of these amplitudes on the shape of the initial perturbation, the angular dependence of the mode, and the black hole spin, comparing against results from perturbation theory in the so-called asymptotic approximation. We also compare the quasinormal frequencies from our numerical simulations with predictions from perturbation theory, finding excellent agreement. For rapidly rotating black holes (of spin j=0.98) we can extract the quasinormal frequencies of not only the fundamental mode, but also of the first two overtones. Finally we study under what conditions the relative amplitude between given pairs of modes gets maximally excited and present a quantitative analysis of rotational mode-mode coupling. The main conclusions and techniques of our
Coexistence of Multiple Nonlinear States in a Tristable Passive Kerr Resonator
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Miles Anderson
2017-08-01
Full Text Available Passive Kerr cavities driven by coherent laser fields display a rich landscape of nonlinear physics, including bistability, pattern formation, and localized dissipative structures (solitons. Their conceptual simplicity has for several decades offered an unprecedented window into nonlinear cavity dynamics, providing insights into numerous systems and applications ranging from all-optical memory devices to microresonator frequency combs. Yet despite the decades of study, a recent theoretical work has surprisingly alluded to an entirely new and unexplored paradigm in the regime where nonlinearly tilted cavity resonances overlap with one another [T. Hansson and S. Wabnitz, J. Opt. Soc. Am. B 32, 1259 (2015JOBPDE0740-322410.1364/JOSAB.32.001259]. We use synchronously driven fiber ring resonators to experimentally access this regime and observe the rise of new nonlinear dissipative states. Specifically, we observe, for the first time to the best of our knowledge, the stable coexistence of temporal Kerr cavity solitons and extended modulation instability (Turing patterns, and perform real-time measurements that unveil the dynamics of the ensuing nonlinear structure. When operating in the regime of continuous wave tristability, we further observe the coexistence of two distinct cavity soliton states, one of which can be identified as a “super” cavity soliton, as predicted by Hansson and Wabnitz. Our experimental findings are in excellent agreement with theoretical analyses and numerical simulations of the infinite-dimensional Ikeda map that governs the cavity dynamics. The results from our work reveal that experimental systems can support complex combinations of distinct nonlinear states, and they could have practical implications to future microresonator-based frequency comb sources.
Coexistence of Multiple Nonlinear States in a Tristable Passive Kerr Resonator
Anderson, Miles; Wang, Yadong; Leo, François; Coen, Stéphane; Erkintalo, Miro; Murdoch, Stuart G.
2017-07-01
Passive Kerr cavities driven by coherent laser fields display a rich landscape of nonlinear physics, including bistability, pattern formation, and localized dissipative structures (solitons). Their conceptual simplicity has for several decades offered an unprecedented window into nonlinear cavity dynamics, providing insights into numerous systems and applications ranging from all-optical memory devices to microresonator frequency combs. Yet despite the decades of study, a recent theoretical work has surprisingly alluded to an entirely new and unexplored paradigm in the regime where nonlinearly tilted cavity resonances overlap with one another [T. Hansson and S. Wabnitz, J. Opt. Soc. Am. B 32, 1259 (2015), 10.1364/JOSAB.32.001259]. We use synchronously driven fiber ring resonators to experimentally access this regime and observe the rise of new nonlinear dissipative states. Specifically, we observe, for the first time to the best of our knowledge, the stable coexistence of temporal Kerr cavity solitons and extended modulation instability (Turing) patterns, and perform real-time measurements that unveil the dynamics of the ensuing nonlinear structure. When operating in the regime of continuous wave tristability, we further observe the coexistence of two distinct cavity soliton states, one of which can be identified as a "super" cavity soliton, as predicted by Hansson and Wabnitz. Our experimental findings are in excellent agreement with theoretical analyses and numerical simulations of the infinite-dimensional Ikeda map that governs the cavity dynamics. The results from our work reveal that experimental systems can support complex combinations of distinct nonlinear states, and they could have practical implications to future microresonator-based frequency comb sources.
Directory of Open Access Journals (Sweden)
González Vázquez, Araceli
2009-06-01
Full Text Available Intersexuality is considered a critical, subversive and deconstructive tool for the categories of sex and gender, in particular from social constructivist theoretical positions well nurtured by post-estructuralist rethoric. The purpose of this article is to discuss the reception of Foucault’s thought in studies on Intersexuality, explain his concepts and how they are incorporated, and which ideas they contribute to destabilizing or reifying within the current debates.
La Intersexualidad es considerada una herramienta de crítica, subversión y deconstrucción de las categorías sexo y género, singularmente desde posiciones ligadas al constructivismo social y muy nutridas por las retóricas postestructuralistas. La propuesta de este artículo es la de discutir la recepción del pensamiento de Michel Foucault en los estudios sobre la Intersexualidad, y explicar qué conceptos y cómo se incorporan, y qué ideas contribuyen a desestabilizar o reificar dentro de estos debates.
Cugier, Philippe; Struski, Caroline; Blanchard, Michel; Mazurié, Joseph; Pouvreau, Stéphane; Olivier, Frédéric; Trigui, Jihane R.; Thiébaut, Eric
2010-07-01
The macrobenthic community of Mont Saint Michel Bay (English Channel, France) is mainly dominated by filter feeders, including cultivated species (oysters and mussels). An ecological model of the bay was developed, coupling a 2D hydro-sedimentary model and two biological models for primary production and filter-feeder filtration. The filter-feeder model includes three cultivated species ( Mytilus edulis, Crassostrea gigas and Ostrea edulis), one invasive species ( Crepidula fornicata) and eight wild native species ( Abra alba, Cerastoderma edule, Glycymeris glycymeris, Lanice conchilega, Macoma balthica, Paphia rhomboides, Sabellaria alveolata, andSpisula ovalis). For cultivated and invasive species, the production of biodeposits was computed to assess their role in restimulating primary production. Chlorophyll a concentrations appeared to be strongly controlled by the filter feeders. When the pressure of each benthic compartment on phytoplankton was estimated separately wild species and the invasive slipper limpet C.fornicata were shown to be key elements in the control of primary production. Conversely, the role of cultivated species, particularly oysters, was weaker. Feedback due to the mineralization of biodeposits also appears to be crucial to fully evaluate the role of filter feeders in primary production.
A moderna política dos castigos uma perspectiva da punição em Michel Foucault
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Daniel de Souza Lemos
2013-06-01
Full Text Available http://dx.doi.org/10.5007/1806-5023.2013v10n1p114 O presente artigo pretende abordar o conceito de punição, presente na obra do filósofo francês Michel Foucault, a partir das transformações que tal idéia sofreu, com repercussões em todo o Ocidente, especialmente a partir do século XVIII, tomando-se como modelo a sua ocorrência na Sociedade Francesa. Para isso procedeu-se à análise de obras relevantes do pensador estudado, especialmente aquelas em que o mesmo aborda, de forma mais direta, a questão ora examinada. A pesquisa teve como foco inicial a obra “Vigiar e Punir - História da Violência nas Prisões”, escrita em 1975, especialmente a sua segunda parte, “Punição”, em que Foucault, no capítulo segundo, trata da “Punição Generalizada”.
L’individu comme problème phénoménologique chez Hannah Arendt et Michel Henry
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Jan Cerny
2012-12-01
Full Text Available Cette étude, dans un premier temps, apporte des preuves à la possibilité d’interpréter la pensée politique de Hannah Arendt comme un projet phénoménologique original dont le but est d’élever l’apparence de la personne au rang de mode unique de l’apparaître. Puis elle présente brièvement la phénoménologie matérielle de Michel Henry dans laquelle le Soi individuel joue un rôle tout aussi central, puisqu’il est la condition de l’apparence de la vie et le fondement de tout apparaître. En conclusion, l’étude esquisse les conséquences d’une telle position privilégiée du sujet individuel pour la conception théorique de la réalité effective de l’apparaître, de même que pour les problèmes pratiques de l’action de l’homme dans le monde.
"De la modération" de Michel de Montaigne a la inmoderación de Hernán Cortés
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Juan Durán Luzio
2016-04-01
Full Text Available Se postula en este artículo que Michel de Montaigne al concluir su ensayo "De la modération" (I.XXX introduce un párrafo final relativo a Hernán Cortés y la conquista de México, el cual, proveniente de fuentes históricas, le sirve al ensayista para establecer una fuerte ironía sobre los excesos y actos carentes de moderación que han ocurrido en la conquista de América. This article postulates that Michel de Montaigne introduces a final paragraph at the conclusion of his essay "De la modération" (I.XXX, that refers to Hernán Cortés and the conquest of Mexico, which, coming from historical sources, helps the essayist to establish and ironic interpretation of the excesses and inmoderate acts occurred during the conquest of America.
O cortiço e a prisão - vigilãncia e controle: Aluísio Azevedo e Michel Foucault
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Marcio Luiz Carreri
2008-01-01
Full Text Available The current articleintends to analyze the existingrelations between metaficcionhistoriografic and the ideologypresented in the naturalisticromance O Cortiço (1890, fromAluísio Azevedo, by means ofarticulation of a reading fromFoucault’s method. Processingdialogues between apparent anddifferent speech areas, it considersa reflection about control anddiscipline through panoptism, usingas research source the Vigiar epunir book, by Michel Foucault in1975.
2003-01-01
"Michel Spiro was appointed director of the IN2P3, by order of the Minister of Youth, National Education and Research and the Minister of Research and New Technologies on February 17, 2003. He was also appointed director of the Department of Nuclear and Particle Physics of the CNRS by decision of the CNRS Director General on February 21, 2003" (1/2 page).
Dürr, Christian
1995-01-01
The thesis aims at the theoretical foundation of deconstructivist strategies in contemporary feminism with reference to the work of French philosopher Michel Foucault. The feminist tradition of distinguishing between the conceptions of "gender" as a culturally coded form of identity and "sex" as its supposed biological foundation has been criticized by younger feminist thinkers, such as Judith Butler, whose work is related to contemporary postmodern thinking. The work of Butler, for example, ...
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Francisca Tomé da Silva
2017-08-01
Full Text Available Esse artigo teve como objetivo analisar a estrutura e situação econômico-financeira do capital de giro de uma empresa S/A, sob a óptica do modelo de Michel Fleuriet, que propicia uma análise dinâmica financeira. Com a reclassificação das contas, identificou-se três variáveis necessárias pelo modelo de Michel Fleuriet: necessidade de capital de giro (NCG, capital de giro (CDG e saldo de tesouraria (ST. A pesquisa foi realizada nas demonstrações financeiras padronizadas (DFP referentes aos anos de 2014 e 2015 de uma empresa de capital aberto S/A, disponibilizadas no site da empresa e no site da Bolsa de Valores do Estado de São Paulo (BM&FBOVESPA no período de abril e maio de 2016, a empresa apresentou situação sólida nos dois anos, sob a óptica de Michel Fleuriet. Os resultados obtidos apresentaram conformidade com as ideias dos autores utilizados, onde a análise dinâmica na empresa em estudo apontou necessidade de capital de giro, mas com capital de giro superior a essa necessidade, levando ao saldo de tesouraria positivo.
Maximilien Brice
2001-01-01
Photo 01 : Michel Della Negra explains some of the general principles behind CMS to President Iliescu. Photo 04 : Director General Luciano Maiani watches as Romanian President Iliescu signs the CERN guest book
Ethical identification of the subject, and “techniques of the self” in the works of Michel Foucault
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Yu V Yatsutsenko
2016-12-01
Full Text Available We are used to the image of an individual as getting into the social reality created before and without him; however, Michel Foucault questions the genealogy of the modern subject, and states that within a ready-made social reality an individual is not given even to himself. Foucault considers processes and practices of individual self-identification, and modes of subjectivation , i. e. the ways, by which an individual seeks and finds his place in an already and completely configured system of social relations. Foucault develops a specific conceptual tool - “techniques of the self” as sets of representations and practices, by which an individual changes oneself and integrates into some ethical systems (of knowledge, rules of behavior, power relations. “Techniques of the self” are purely social, they do not constitute any ethical identity; on the contrary, they provide a socially determined self-identification. Foucault’s “techniques of the self” let us conceptualize the coincidence of the seemingly anonymous processes of governing and individual self-definition; these techniques serve as indicators of individual ethical normalization. Identification of the “techniques of the self” in subjects’ actions helps to define the governing processes not as a violent submission, but as a basic state of the social interaction systems. In order to verify the heuristic potential of the “techniques of the self” concept, the author considers ancient and early Christian models of subjectivation, which Foucault opposed as two ethical models of subject’s access to the “truths”. With the ancient ethical “techniques of the self”, a subject is a full-fledged ethical agent; with the early Christian techniques, he is to accept one’s ontological inability to establish the righteousness based only on one’s personal experience. For example, such an opposition helps to explain differences between tutorship forms and self-control goals.
From Life to Existence: A Reconsideration of the Question of Intentionality in Michel Henry’s Ethics
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Frédéric Seyler
2012-12-01
Full Text Available Michel Henry has renewed our understanding of life as immanent affectivity: life cannot be reduced to what can be made visible; it is – as immanent and as affectivity – radically invisible. However, if life (la vie is radically immanent, the living (le vivant has nonetheless to relate to the world: it has to exist. But, since existence requires and includes intentional components, human reality – being both living and existing – implies that immanence and intentionality be related to one another, even though they are conceived at the same time as radically distinct modes of appearing in Henry’s phenomenology of life. Following this line of thought, we are faced with at least two questions: First, what reality does immanent appearing have for us as existing and intentional beings? And second, from an ethical point of view, what does Henry’s opposition of “barbarism” and “second birth” mean in terms of existence? As will be shown, it follows from the standpoint of radical phenomenology itself that immanent affectivity has reality for us only insofar as it finds its expression or translation in the realm of the intentionally visible and that, with regard to ethics, both “barbarism” and its overcoming in “second birth” are effective only insofar as they are mediated through representations. Henry’s critique of representation and intentionality needs therefore to be revised, especially in the field of practical philosophy, where the essential role played by intentionality has to be acknowledged even by radical phenomenology.
Racismo de estado e tanatopolítica: Sobre o paradoxo do nazismo em Michel Foucault e Giorgio Agamben
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Francisco Bruno Pereira Diógenes
2013-12-01
Full Text Available Este artigo propõe-se a expor as reflexões de dois filósofos contemporâneos, quais sejam, Michel Foucault e Giorgio Agamben, de modo a promover um paralelo,ou mesmo uma analogia, entre duas noções que permeiam as obras dos respectivos autores. Estas noções consistem no que Foucault chamou de Racismo de Estado, e no que Agamben nomeou de Tanatopolítica. O contexto, e tambémo objeto, no qual se efetiva este intento é, em uma palavra, a política totalitária do Estado nazista.Ambos os autores compreendem os fenômenos totalitários a partir do ponto de vista da biopolítica, entretanto, ao tratar do Estado Nacional-socialista, Foucault identifica nele um paradoxo, sem, contudo desenvolver com maior profundidade a imbricação que ali se deu. Agamben, por sua vez, concebe semelhante paradoxo como pertencendo a uma forma de fazer política que já traz, desde a sua origem, os fundamentos que permitiram a emergência do fenômeno da forma como surgiu e que fora identificada pelos ditos autores, ou seja, trazendo em si tanto elementos antigos, como a glória e os ideais de sangue, quanto modernos, como a eugenia. A pesquisa bibliográfica que aqui se desenvolveu deu-se na leitura de, basicamente, três obras dos supraditos autores, quais sejam, Em defesa da sociedade, História da sexualidade I – A vontade de saber, de um lado (Foucault, e Homo sacer – O poder soberano e a vida nua I, de outro (Agamben.
Health hazard evaluation report HETA 82-361-1437, Kerr-McGee Nuclear Corporation, Grants, New Mexico
International Nuclear Information System (INIS)
Ward, E.M.; Smith, A.B.; Thun, M.J.; Hills, B.
1984-03-01
A health-hazard evaluation at Kerr/McGee Nuclear Corporation's uranium (7440611) mill (SIC-1094) in Grants, New Mexico was conducted in November, 1982. Evaluation was requested because of union concern about exposure and possible nephrotoxic effects of yellowcake, a concentrate of natural uranium, produced at the mill. Personnel records, company environmental and personal monitoring, and urine uranium bioassay data were reviewed. Further medical evaluation at the facility is not warranted as the longest exposure to yellowcake was only 7 years. The authors recommend that Kerr/McGee use the NRC guidelines for assessing exposure. Emission source in the drier and precipitation area should be identified and engineering controls installed to reduce the exposure
Nonequatorial tachyon trajectories in Kerr space-time and the second law of black-hole physics
International Nuclear Information System (INIS)
Dhurandhar, S.V.
1979-01-01
The behavior of tachyon trajectories (spacelike geodesics) in Kerr space-time is discussed. It is seen that the trajectories may be broadly classified into three types according to the magnitude of the angular momentum of the tachyon. When the magnitude of angular momentum is large [vertical-barhvertical-bar > or = a (1 + GAMMA 2 )atsup 1/2at, where h and GAMMA are the angular momentum and energy at infinity and a 0. In the other cases, a negative value for Carter's constant of motion Q is permitted, which happens to be a necessary condition for the tachyon to fall into the singularity. Next, the second law of black-hole physics is investigated in the general case of nonequatorial trajectories. It is shown that nonequatorial tachyons can decrease the area of the Kerr black hole only if it is rotating sufficiently rapidly [a > (4/3√3) M
Energy Technology Data Exchange (ETDEWEB)
Garcia-Lechuga, Mario, E-mail: mario@io.cfmac.csic.es; Siegel, Jan, E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, Javier; Solis, Javier [Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, 28006 Madrid (Spain)
2014-09-21
The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550 fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.
International Nuclear Information System (INIS)
Garcia-Lechuga, Mario; Siegel, Jan; Hernandez-Rueda, Javier; Solis, Javier
2014-01-01
The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550 fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.
The Carter constant for inclined orbits about a massive Kerr black hole: I. Circular orbits
Energy Technology Data Exchange (ETDEWEB)
Komorowski, P G; Valluri, S R; Houde, M, E-mail: pkomorow@uwo.c, E-mail: valluri@uwo.c, E-mail: mhoude2@uwo.c [Department of Physics and Astronomy, University of Western Ontario, London, Ontario (Canada)
2010-11-21
In an extreme binary black hole system, an orbit will increase its angle of inclination ({iota}) as it evolves in Kerr spacetime. We focus our attention on the behaviour of the Carter constant (Q) for near-polar orbits, and develop an analysis that is independent of and complements radiation-reaction models. For a Schwarzschild black hole, the polar orbits represent the abutment between the prograde and retrograde orbits at which Q is at its maximum value for given values of the latus rectum ({tilde l}) and the eccentricity (e). The introduction of spin ({tilde S}={vert_bar}J{vert_bar}/M{sup 2}) to the massive black hole causes this boundary, or abutment, to be moved towards greater orbital inclination; thus, it no longer cleanly separates prograde and retrograde orbits. To characterize the abutment of a Kerr black hole (KBH), we first investigated the last stable orbit (LSO) of a test-particle about a KBH, and then extended this work to general orbits. To develop a better understanding of the evolution of Q we developed analytical formulae for Q in terms of {tilde l}, e and {tilde S} to describe elliptical orbits at the abutment, polar orbits and LSOs. By knowing the analytical form of {partial_derivative}Q/{partial_derivative}{tilde l} at the abutment, we were able to test a 2PN flux equation for Q. We also used these formulae to numerically calculate the {partial_derivative}{iota}/{partial_derivative}{tilde l} of hypothetical circular orbits that evolve along the abutment. From these values we have determined that {partial_derivative}{iota}/{partial_derivative}{tilde l} = -(122.7{tilde S} - 36{tilde S}{sup 3}){tilde l}{sup -11/2} - (63/2 {tilde S} + 35/4 {tilde S}{sup 3}){tilde l}{sup -9/2} - 15/2 {tilde S}{tilde l}{sup -7/2} - 9/2 {tilde S}{tilde l}{sup -5/2}. By taking the limit of this equation for {tilde l} {yields} {infinity}, and comparing it with the published result for the weak-field radiation reaction, we found the upper limit on
Zhu, X D
2017-08-01
I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.
International Nuclear Information System (INIS)
Vujic, Dragan; John, Sajeev
2005-01-01
We delineate critical issues for 'controlling light with light' in photonic crystal (PC) waveguides coupled to Kerr-nonlinear microresonators. These arise from (a) fundamental trade-off between switching speed and switching intensity threshold inherent in high-quality Q-factor cavities and (b) the dynamical nonlinear oscillation of such cavities in response to incident light pulses. Using finite-difference time-domain simulations of electromagnetic pulse propagation, we consider both (i) a nonlinear Fabry-Perot microresonator (embedded within a PC waveguide) exhibiting a narrow transmission resonance and (ii) a nonlinear point defect (side-coupled to a PC waveguide) exhibiting a narrow reflection spectrum. We describe self-induced switching from transmission to reflection induced by pulse intensity tuning as well as control of pulse transmission induced by the secondary, continuous (cw) laser field propagating through the same PC waveguide. For the Fabry-Perot microresonator, a well-defined self-switching threshold is obtained. However, this is accompanied by considerable temporal and spectral distortion of the pulse caused by the oscillatory nonlinear response of the microresonator. When the quality factor of the microresonator is increased, the switching intensity threshold can be lowered but the pulse transit (switching) time and the pulse distortion are increased. For the side-coupled microresonator, a gradual (not sharp) self-switching behavior as a function of incident intensity is obtained. For both the Fabry-Perot and side-coupled nonlinear microresonators, control of pulse transmission can be achieved by means of a secondary cw laser field. The cw power required for switching with realistic Kerr nonlinearities is in excess of 1 W/μm 2 and may cause optical damage to the semiconducting PC backbone. Both instantaneous and noninstantaneous Kerr-response models are considered. Our results underscore the limitations and trade-offs inherent in the possible
Direct observation of magnetic domains by Kerr microscopy in a Ni-Mn-Ga magnetic shape-memory alloy
Czech Academy of Sciences Publication Activity Database
Perevertov, Oleksiy; Heczko, Oleg; Schaefer, R.
2017-01-01
Roč. 95, č. 14 (2017), s. 1-5, č. článku 144431. ISSN 2469-9950 R&D Projects: GA ČR GA15-00262S Institutional support: RVO:68378271 Keywords : shape memory * magnetic domains * Kerr microscopy * N-Mn-Ga alloy Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016
Energy Technology Data Exchange (ETDEWEB)
de Felice, F; Nobili, L [Padua Univ. (Italy). Istituto di Fisica; Calvani, M [Padua univ. (Italy). Istituto di Astronomia
1976-03-01
The existence of extended Kerr metric sources of perfect fluid is taken as work-hypothesis to investigate the structure of the boundaries which derive from Boyer's surface condition. We find closed spheroidal configurations which hide an internal cavity as well as toroidal configurations; however, both the boundary of the internal cavity and the tori touch the ring singularity. We judge this feature non-physical and conclude that Boyer's condition is not sufficient to completely define a well behaved physical source.
SOLUCIÓN DE LA ECUACIÓN NO LINEAL DE SCHRODINGER (1+1 EN UN MEDIO KERR
Directory of Open Access Journals (Sweden)
Francis Armando Segovia
2015-12-01
Full Text Available Se presenta un marco teórico y se muestra una simulación numérica de la propagación de solitones. Con especial atención a los solitones ópticos espaciales, se calcula analíticamente el perfil de solitón correspondiente a la ecuación Schrodinger no-lineal para un medio Kerr. Los resultados muestran que los solitones ópticos son pulsos estables cuya forma y espectro son preservados en grandes distancias.Solution of the nonlinear Schrodinger equation (1+1 in a Kerr mediumABSTRACTThis document presents a theoretical framework and shows a numerical simulation for the propagation of solitons. With special attention to the spatial optical solitons, we calculates analytically the profile of solitón corresponding to the non-linear Schrodinger equation for a Kerr medium. The results show that the optical solitons are stable pulses whose shape and spectrum are preserved at great distances.Keywords: nonlinear optics, nonlinear Schrodinger equation, solitons.
Near-field thermal upconversion and energy transfer through a Kerr medium.
Khandekar, Chinmay; Rodriguez, Alejandro W
2017-09-18
We present an approach for achieving large Kerr χ (3) -mediated thermal energy transfer at the nanoscale that exploits a general coupled-mode description of triply resonant, four-wave mixing processes. We analyze the efficiency of thermal upconversion and energy transfer from mid- to near-infrared wavelengths in planar geometries involving two slabs supporting far-apart surface plasmon polaritons and separated by a nonlinear χ (3) medium that is irradiated by externally incident light. We study multiple geometric and material configurations and different classes of intervening mediums-either bulk or nanostructured lattices of nanoparticles embedded in nonlinear materials-designed to resonantly enhance the interaction of the incident light with thermal slab resonances. We find that even when the entire system is in thermodynamic equilibrium (at room temperature) and under typical drive intensities ~ W/μm 2 , the resulting upconversion rates can approach and even exceed thermal flux rates achieved in typical symmetric and non-equilibrium configurations of vacuum-separated slabs. The proposed nonlinear scheme could potentially be exploited to achieve thermal cooling and refrigeration at the nanoscale, and to actively control heat transfer between materials with dramatically different resonant responses.
Thermodynamics, stability and Hawking-Page transition of Kerr black holes from Renyi statistics
Energy Technology Data Exchange (ETDEWEB)
Czinner, Viktor G. [University of Lisbon, Multidisciplinary Center for Astrophysics and Department of Physics, Instituto Superior Tecnico, Lisboa (Portugal); HAS Wigner Research Centre for Physics, Budapest (Hungary); Iguchi, Hideo [Nihon University, Laboratory of Physics, College of Science and Technology, Funabashi, Chiba (Japan)
2017-12-15
Thermodynamics of rotating black holes described by the Renyi formula as equilibrium and zeroth law compatible entropy function is investigated. We show that similarly to the standard Boltzmann approach, isolated Kerr black holes are stable with respect to axisymmetric perturbations in the Renyi model. On the other hand, when the black holes are surrounded by a bath of thermal radiation, slowly rotating black holes can also be in stable equilibrium with the heat bath at a fixed temperature, in contrast to the Boltzmann description. For the question of possible phase transitions in the system, we show that a Hawking-Page transition and a first order small black hole/large black hole transition occur, analogous to the picture of rotating black holes in AdS space. These results confirm the similarity between the Renyi-asymptotically flat and Boltzmann-AdS approaches to black hole thermodynamics in the rotating case as well. We derive the relations between the thermodynamic parameters based on this correspondence. (orig.)
Self-force as a cosmic censor in the Kerr overspinning problem
Colleoni, Marta; Barack, Leor; Shah, Abhay G.; van de Meent, Maarten
2015-10-01
It is known that a near-extremal Kerr black hole can be spun up beyond its extremal limit by capturing a test particle. Here we show that overspinning is always averted once backreaction from the particle's own gravity is properly taken into account. We focus on nonspinning, uncharged, massive particles thrown in along the equatorial plane and work in the first-order self-force approximation (i.e., we include all relevant corrections to the particle's acceleration through linear order in the ratio, assumed small, between the particle's energy and the black hole's mass). Our calculation is a numerical implementation of a recent analysis by two of us [Phys. Rev. D 91, 104024 (2015)], in which a necessary and sufficient "censorship" condition was formulated for the capture scenario, involving certain self-force quantities calculated on the one-parameter family of unstable circular geodesics in the extremal limit. The self-force information accounts both for radiative losses and for the finite-mass correction to the critical value of the impact parameter. Here we obtain the required self-force data and present strong evidence to suggest that captured particles never drive the black hole beyond its extremal limit. We show, however, that, within our first-order self-force approximation, it is possible to reach the extremal limit with a suitable choice of initial orbital parameters. To rule out such a possibility would require (currently unavailable) information about higher-order self-force corrections.
STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS
International Nuclear Information System (INIS)
Wang Yan; Li Xiangdong
2012-01-01
If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.
Dynamics of particles around a pseudo-Newtonian Kerr black hole with halos
International Nuclear Information System (INIS)
Wang Ying; Wu Xin
2012-01-01
The regular and chaotic dynamics of test particles in a superposed field between a pseudo-Newtonian Kerr black hole and quadrupolar halos is detailed. In particular, the dependence of dynamics on the quadrupolar parameter of the halos and the spin angular momentum of the rotating black hole is studied. It is found that the small quadrupolar moment, in contrast with the spin angular momentum, does not have a great effect on the stability and radii of the innermost stable circular orbits of these test particles. In addition, chaos mainly occurs for small absolute values of the rotating parameters, and does not exist for the maximum counter-rotating case under some certain initial conditions and parameters. This means that the rotating parameters of the black hole weaken the chaotic properties. It is also found that the counter-rotating system is more unstable than the co-rotating one. Furthermore, chaos is absent for small absolute values of the quadrupoles, and the onset of chaos is easier for the prolate halos than for the oblate ones. (general)
Kerr hysteresis loop tracer with alternate driving magnetic field up to 10 kHz
Callegaro, Luca; Fiorini, Carlo; Triggiani, Giacomo; Puppin, Ezio
1997-07-01
A magneto-optical Kerr loop tracer for hysteresis loop measurements in thin films with field excitation frequency f0 from 10 mHz to 10 kHz is described. A very high sensitivity is obtained by using an ultrabright light-emitting diode as a low-noise light source and a novel acquisition process. The field is generated with a coil driven by an audio amplifier connected to a free-running oscillator. The conditioned detector output constitutes the magnetization signal (M); the magnetic field (H) is measured with a fast Hall probe. The acquisition electronics are based on a set of sample-and-hold amplifiers which allow the simultaneous sampling of M, H, and dH/dt. Acquisition is driven by a personal computer equipped with a multifunction I/O board. Test results on a 120 nm Fe film on Si substrate are shown. The coercive field of the film increases with frequency and nearly doubles at 10 kHz with respect to dc.
Asymptotic symmetries on the Kerr-Newman horizon without the anomaly of diffeomorphism invariance
International Nuclear Information System (INIS)
Koga, Jun-ichirou
2008-01-01
We analyze asymptotic symmetries on the Killing horizon of the four-dimensional Kerr-Newman black hole. We first derive the asymptotic Killing vectors on the Killing horizon, which describe the asymptotic symmetries, and find that the general form of these asymptotic Killing vectors is the universal one possessed by arbitrary Killing horizons. We then construct the phase space associated with the asymptotic symmetries. It is shown that the phase space of an extreme black hole either has the size comparable with a non-extreme black hole, or is small enough to exclude degeneracy, depending on whether or not the global structure of a Killing horizon particular to an extreme black hole is respected. We also show that the classical central charge in the Poisson brackets algebra of these asymptotic symmetries vanishes, which implies that there is not an anomaly of diffeomorphism invariance. By taking into account other results in the literature, we argue that the vanishing central charge on a black hole horizon, in an effective theory, looks consistent with the thermal feature of a black hole. We furthermore argue that the vanishing central charge implies that there are sufficiently many classical configurations that constitute a single macroscopic state, while these configurations are distinguished physically
Kerr microscopy studies of the effects of bending stress on galfenola)
Raghunath, Ganesh; Marana, Michael; Na, Suok-Min; Flatau, Alison
2014-05-01
This work deals with using a magneto-optic Kerr effect (MOKE) microscope to optically analyze the evolution of magnetic domains in a rolled and Goss textured galfenol (Fe81Ga19 + 1.0% NbC) sample when subjected to a bending stress. The initial magnetization state of the cantilevered sample was fixed along its length by a 0.3 T permanent magnet. The magnetic state was monitored with the MOKE microscope as a tip load was applied to bend the sample. The magnetic state of galfenol depends on its magneto-elastic properties. A finite element model that incorporates an energy based formulation of magnetostriction [W. D. Armstrong, J. Magn. Magn. Mater. 263(1-2), 208-218 (2003)] was used to investigate the stresses in the sample and the corresponding change in the magnetic induction as bending occurred. A qualitative comparison with the domain pictures is presented, and the experimental micromagnetic behavior results are shown to correlate well to the macro scale bending stress and magnetization results obtained in the FEM simulations.
Depth profiling of calcifications in breast tissue using picosecond Kerr-gated Raman spectroscopy.
Baker, Rebecca; Matousek, Pavel; Ronayne, Kate Louise; Parker, Anthony William; Rogers, Keith; Stone, Nicholas
2007-01-01
Breast calcifications are found in both benign and malignant lesions and their composition can indicate the disease state. Calcium oxalate (dihydrate) (COD) is associated with benign lesions, however calcium hydroxyapatite (HAP) is found mainly in proliferative lesions including carcinoma. The diagnostic practices of mammography and histopathology examine the morphology of the specimen. They can not reliably distinguish between the two types of calcification, which may indicate the presence of a cancerous lesion during mammography. We demonstrate for the first time that Kerr-gated Raman spectroscopy is capable of non-destructive probing of sufficient biochemical information from calcifications buried within tissue, and this information can potentially be used as a first step in identifying the type of lesion. The method uses a picosecond pulsed laser combined with fast temporal gating of Raman scattered light to enable spectra to be collected from a specific depth within scattering media by collecting signals emerging from the sample at a given time delay following the laser pulse. Spectra characteristic of both HAP and COD were obtained at depths of up to 0.96 mm, in both chicken breast and fatty tissue; and normal and cancerous human breast by utilising different time delays. This presents great potential for the use of Raman spectroscopy as an adjunct to mammography in the early diagnosis of breast cancer.
Soft-x-ray magneto-optical Kerr effect and element-specific hysteresis measurement
Energy Technology Data Exchange (ETDEWEB)
Kortright, J.B.; Rice, M. [Lawrence Berkeley National Lab., CA (United States)
1997-04-01
Interest in the utilization of x-ray magneto-optical properties to provide element-specific magnetic information, combined with recent development of tunable linear polarizers for spectroscopic polarization measurement, have led the authors to the study of magneto-optical rotation (MOR) near core levels of magnetic atoms in magnetic multilayer and alloy films. Their initial observation of Faraday rotation (in transmission) demonstrated that for Fe MOR is easily measured and is larger at its L{sub 3} resonance than in the near-visible spectral regions. This work also demonstrated that the spectroscopic behavior of the MOR signal in transmission, resulting from the differential reaction of left- and right-circular components of a linearly polarized beam, is related to the magnetic circular dichroism (MCD), or differential absorption, as expected by a Kramers-Kronig transformation. Thus MCD measurements using circular polarization and MOR measurements using linear polarization can provide complementary, and in some cases equivalent, information. On beamline 6.3.2 the authors have begun to investigate soft x-ray MOR in the reflection geometry, the x-ray magneto-optic Kerr effect (XMOKE). Early measurements have demonstrated the ability to measure element-specific hysteresis loops and large rotations compared to analogous near-visible measurements. The authors are investigating the spectral dependence of the XMOKE signal, and have initiated systematic materials studies of sputter-deposited films of Fe, Fe{sub x}Cr{sub 1{minus}x} alloys, and Fe/Cr multilayers.
Energy Technology Data Exchange (ETDEWEB)
Jia, Baoping, E-mail: baoping.jia@cczu.edu.cn [Changzhou University, School of Materials Science and Engineering (China); Zhang, Wei, E-mail: wei.zhang@unisa.edu.au [University of Tokyo, Department of Urban Engineering (Japan); Liu, Hui [Central South University, School of Metallurgy and Environment, National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (China); Lin, Bencai; Ding, Jianning [Changzhou University, School of Materials Science and Engineering (China)
2016-09-15
Heterostructured multilayer films of two different nanocrystals have been successfully fabricated by layer-by-layer stacking of Ti{sub 0.8}Co{sub 0.2}O{sub 2} nanosheet and Fe{sub 3}O{sub 4} nanoparticle films. UV–Vis spectroscopy and AFM observation confirmed the successful alternating deposition in the multilayer buildup process. The average thickness of both Ti{sub 0.8}Co{sub 0.2}O{sub 2} nanosheet and Fe{sub 3}O{sub 4} nanoparticle layers was determined to be about 1.4–1.7 and 5 nm, which was in good agreement with TEM results. Magneto-optical Kerr effect measurements demonstrated that the heteroassemblies exhibit gigantic magnetic circular dichroism (MCD) (2 × 10{sup 4} deg/cm) at 320–360 nm, deriving from strong interlayer [Co{sup 2+}]t{sub 2g}–[Fe{sup 3+}]e{sub g} d–d charge transfer which was further confirmed by X-ray photoelectron spectroscopy. Their structure-dependent MCD showed high potential in rational design and construction of high-efficiency magneto-optical devices.
Mass, angular momentum and thermodynamics in four-dimensional Kerr-AdS black holes
Energy Technology Data Exchange (ETDEWEB)
Olea, Rodrigo [Departamento de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)
2005-06-01
In this paper, the connection between the Lorentz-covariant counterterms that regularize the four-dimensional AdS gravity action and topological invariants is explored. It is shown that demanding the spacetime to have a negative constant curvature in the asymptotic region permits the explicit construction of such series of boundary terms. The orthonormal frame is adapted to appropriately describe the boundary geometry and, as a result, the boundary term can be expressed as a functional of the boundary metric, extrinsic curvature and intrinsic curvature. This choice also allows to write down the background-independent Noether charges associated to asymptotic symmetries in standard tensorial formalism. The absence of the Gibbons-Hawking term is a consequence of an action principle based on a boundary condition different than Dirichlet on the metric. This argument makes plausible the idea of regarding this approach as an alternative regularization scheme for AdS gravity in all even dimensions, different than the standard counterterms prescription. As an illustration of the finiteness of the charges and the euclidean action in this framework, the conserved quantities and black hole entropy for four-dimensional Kerr-AdS are computed.
X-ray Pulse Length Characterization using the Surface Magneto Optic Kerr Effect
International Nuclear Information System (INIS)
Krejcik, P.; SLAC
2006-01-01
It will be challenging to measure the temporal profile of the hard X-ray SASE beam independently from the electron beam in the LCLS and other 4th generation light sources. A fast interaction mechanism is needed that can be probed by an ultrafast laser pulse in a pump-probe experiment. It is proposed to exploit the rotation in polarization of light reflected from a thin magnetized film, known as the surface magneto optic Kerr effect (SMOKE), to witness the absorption of the x-ray pulse in the thin film. The change in spin orbit coupling induced by the x-ray pulse occurs on the subfemtosecond time scale and changes the polarization of the probe beam. The limitation to the technique lies with the bandwidth of the probe laser pulse and how short the optical pulse can be made. The SMOKE mechanism will be described and the choices of materials for use with 1.5 (angstrom) x-rays. A schematic description of the pump-probe geometry for x-ray diagnosis is also described
International Nuclear Information System (INIS)
Pinotti, E.; Brenna, M.; Puppin, E.
2008-01-01
In magneto-optical Kerr measurements of the Barkhausen noise, a magnetization jump ΔM due to a domain reversal produces a variation ΔI of the intensity of a laser beam reflected by the sample, which is the physical quantity actually measured. Due to the non-uniform beam intensity profile, the magnitude of ΔI depends both on ΔM and on its position on the laser spot. This could distort the statistical distribution p(ΔI) of the measured ΔI with respect to the true distribution p(ΔM) of the magnetization jumps ΔM. In this work the exact relationship between the two distributions is derived in a general form, which will be applied to some possible beam profiles. It will be shown that in most cases the usual Gaussian beam produces a negligible statistical distortion. Moreover, for small ΔI the noise of the experimental setup can also distort the statistical distribution p(ΔI), by erroneously rejecting small ΔI as noise. This effect has been calculated for white noise, and it will be shown that it is relatively small but not totally negligible as the measured ΔI approaches the detection limit
Probabilistically cloning two single-photon states using weak cross-Kerr nonlinearities
International Nuclear Information System (INIS)
Zhang, Wen; Rui, Pinshu; Zhang, Ziyun; Yang, Qun
2014-01-01
By using quantum nondemolition detectors (QNDs) based on weak cross-Kerr nonlinearities, we propose an experimental scheme for achieving 1→2 probabilistic quantum cloning (PQC) of a single-photon state, secretly choosing from a two-state set. In our scheme, after a QND is performed on the to-be-cloned photon and the assistant photon, a single-photon projection measurement is performed by a polarization beam splitter (PBS) and two single-photon trigger detectors (SPTDs). The measurement is to judge whether the PQC should be continued. If the cloning fails, a cutoff is carried out and some operations are omitted. This makes our scheme economical. If the PQC is continued according to the measurement result, two more QNDs and some unitary operations are performed on the to-be-cloned photon and the cloning photon to achieve the PQC in a nearly deterministic way. Our experimental scheme for PQC is feasible for future technology. Furthermore, the quantum logic network of our PQC scheme is presented. In comparison with similar networks, our PQC network is simpler and more economical. (paper)
International Nuclear Information System (INIS)
Jia, Baoping; Zhang, Wei; Liu, Hui; Lin, Bencai; Ding, Jianning
2016-01-01
Heterostructured multilayer films of two different nanocrystals have been successfully fabricated by layer-by-layer stacking of Ti_0_._8Co_0_._2O_2 nanosheet and Fe_3O_4 nanoparticle films. UV–Vis spectroscopy and AFM observation confirmed the successful alternating deposition in the multilayer buildup process. The average thickness of both Ti_0_._8Co_0_._2O_2 nanosheet and Fe_3O_4 nanoparticle layers was determined to be about 1.4–1.7 and 5 nm, which was in good agreement with TEM results. Magneto-optical Kerr effect measurements demonstrated that the heteroassemblies exhibit gigantic magnetic circular dichroism (MCD) (2 × 10"4 deg/cm) at 320–360 nm, deriving from strong interlayer [Co"2"+]t_2_g–[Fe"3"+]e_g d–d charge transfer which was further confirmed by X-ray photoelectron spectroscopy. Their structure-dependent MCD showed high potential in rational design and construction of high-efficiency magneto-optical devices.
YNOGK: A NEW PUBLIC CODE FOR CALCULATING NULL GEODESICS IN THE KERR SPACETIME
Energy Technology Data Exchange (ETDEWEB)
Yang Xiaolin; Wang Jiancheng, E-mail: yangxl@ynao.ac.cn [National Astronomical Observatories, Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 (China)
2013-07-01
Following the work of Dexter and Agol, we present a new public code for the fast calculation of null geodesics in the Kerr spacetime. Using Weierstrass's and Jacobi's elliptic functions, we express all coordinates and affine parameters as analytical and numerical functions of a parameter p, which is an integral value along the geodesic. This is the main difference between our code and previous similar ones. The advantage of this treatment is that the information about the turning points does not need to be specified in advance by the user, and many applications such as imaging, the calculation of line profiles, and the observer-emitter problem, become root-finding problems. All elliptic integrations are computed by Carlson's elliptic integral method as in Dexter and Agol, which guarantees the fast computational speed of our code. The formulae to compute the constants of motion given by Cunningham and Bardeen have been extended, which allow one to readily handle situations in which the emitter or the observer has an arbitrary distance from, and motion state with respect to, the central compact object. The validation of the code has been extensively tested through applications to toy problems from the literature. The source FORTRAN code is freely available for download on our Web site http://www1.ynao.ac.cn/{approx}yangxl/yxl.html.
YNOGK: A NEW PUBLIC CODE FOR CALCULATING NULL GEODESICS IN THE KERR SPACETIME
International Nuclear Information System (INIS)
Yang Xiaolin; Wang Jiancheng
2013-01-01
Following the work of Dexter and Agol, we present a new public code for the fast calculation of null geodesics in the Kerr spacetime. Using Weierstrass's and Jacobi's elliptic functions, we express all coordinates and affine parameters as analytical and numerical functions of a parameter p, which is an integral value along the geodesic. This is the main difference between our code and previous similar ones. The advantage of this treatment is that the information about the turning points does not need to be specified in advance by the user, and many applications such as imaging, the calculation of line profiles, and the observer-emitter problem, become root-finding problems. All elliptic integrations are computed by Carlson's elliptic integral method as in Dexter and Agol, which guarantees the fast computational speed of our code. The formulae to compute the constants of motion given by Cunningham and Bardeen have been extended, which allow one to readily handle situations in which the emitter or the observer has an arbitrary distance from, and motion state with respect to, the central compact object. The validation of the code has been extensively tested through applications to toy problems from the literature. The source FORTRAN code is freely available for download on our Web site http://www1.ynao.ac.cn/~yangxl/yxl.html.
Exploring DC-Kerr effect of impurity doped quantum dots under the aegis of noise
Arif, Sk. Md.; Bera, Aindrila; Ghosh, Anuja; Ghosh, Manas
2018-02-01
Present study performs an extensive exploration of the profiles of DC-Kerr effect (DCKE) of doped GaAs quantum dot (QD) under the control of Gaussian white noise. A large number of important physical parameters have been varied over a range and the resultant changes in the DCKE profiles have been thoroughly analyzed. The said physical parameters comprise of electric field, magnetic field, confinement potential, dopant location, dopant potential, noise strength, aluminium concentration (only for Alx Ga1 - x As alloy QD), carrier density, relaxation time, position-dependent effective mass (PDEM), position-dependent dielectric screening function (PDDSF), anisotropy, hydrostatic pressure (HP) and temperature. The particular physical quantity being varied, presence of noise and its pathway of application, in combination, lead to emergence of diverse features in the DCKE profiles. As a technologically significant aspect we often find maximization of DCKE for some typical combinations as mentioned above. Presence of multiplicative noise, in general, causes greater shift and greater augmentation of DCKE profiles from a noise-free condition than its additive counterpart. The outcomes of the study indicate ample scope of tailoring DCKE of doped QD systems in presence of noise by minute adjustment of several control parameters.
Caracterización de harina y almidón de frutos de banano Gros Michel (Musa acuminata AAA
Directory of Open Access Journals (Sweden)
Jairo Montoya-López
2015-01-01
Full Text Available En el estudio se determinaron las características fisicoquímicas, térmicas y reológicas de la harina y el almidón de frutos de banano Gros Michel (Musa acuminata cosechado en fincas del departamento del Quindío, Colombia. En el análisis proximal, la harina presentó un contenido de fibra de 18.82% y el almidón presentó contenidos de proteína de 1.92%, grasa de 5.3% y fibra de 2.76%. La harina presentó la temperatura más alta de absorción de calor (68.88 °C y su entalpía de gelatinización fue de 2.17 J/g; mientras que para el almidón estos valores fueron de 48.36 °C y 44.62 J/g, respectivamente. El análisis termogravimétrico (TGA de la harina o temperaturas en las cuales se registra la descomposición de carbohidratos (componentes de bajo peso molecular y polisacáridos (componentes de alto peso molecular fueron, respectivamente, de 284.51 °C y 470.42 °C; y para el almidón fueron de 307.51 °C y 500.46 °C. Los gránulos de almidón de banano tienen forma elipsoidal con un tamaño longitudinal promedio de 39.39 µm y tamaño transversal promedio de 29.47 µm. Los difractogramas de rayos X mostraron patrones de difracción tipo B. Los viscoamilogramas mostraron que para la harina la temperatura de inicio de gelatinización (Tg es de 76.3 °C, la viscosidad máxima de 1120 cP, y para el almidón la Tg fue de 70.75 °C y la viscosidad máxima de 2087 cP.
Às voltas com a História da Loucura: um percurso intelectual de Michel Foucault
Directory of Open Access Journals (Sweden)
Elton Corbanezi
2010-06-01
Full Text Available Trata-se de compreender o projeto em História da Loucura na Idade Clássica [1961] como um élan à trajetória intelectual de Foucault, a qual problematiza a racionalidade das nossas relações com o Outro da cultura ocidental, isto é, com aquele que reside historicamente no não dito. Para tanto, torna-se necessário discutir as implicações sociais a partir da oposição entre o normal e o patológico, de modo a ressaltar uma questão fundamental em sua tese de 1961, a saber: de que maneira o louco, como representante de uma das experiências limite problematizadas por Foucault, passou a ser concebido como o Outro a ser recusado pela racionalidade ocidental. Desse modo, por meio de sua análise histórico- filosófica e da demonstração da crescente subordinação da loucura à razão – a partir da qual se torna possível a emergência da loucura e de suas redes de controle social –, trata-se de evidenciar de que modo o homem, como um objeto fictício de si, aparece como uma problematização já em seus primeiros escritos. Às voltas com as embrionárias reflexões e problematizações das (não relações que se tem com os saberes sujeitados da cultura ocidental, confere-se a contribuição de Michel Foucault à filosofia contemporânea, em sua tarefa crítica do pensamento que implica a arte de não ser governado pela verdade em sentido a-histórico.
Bobák, Alexander
2015-01-01
This thesis analyzes the position of the author in the environment of internet. The main source of information for this thesis is the study of Roland Barthes - Death of the Author and the lecture of Michel Foucault - What is an author? After a thorough analysis of these two works, the thesis focuses on the description of the webpage www.pismak.cz, which has been selected as a suitable representative for environment of internet. This website allows us to study and explore the role and place of...
La noción de enunciado rector de Michel Foucault y el análisis de objetos discursivos mediáticos
Voss, Jefferson; Navarro, Pedro
2013-01-01
Este texto tem como escopo discorrer sobre a noção de enunciado reitor, erigida no interior do método arqueológico de Michel Foucault, e discutir sua operacionalidade para a Análise de Discurso (AD). Para tanto, arguimos, primeiramente, sobre as possibilidades de trabalho com o método arqueológico. Na sequência, apresentamos algumas ressalvas que precisariam ser feitas diante da especificidade de algumas materialidades discursivas contemporâneas. Essas ressalvas dizem respeito a algumas noçõe...
Directory of Open Access Journals (Sweden)
Nickel, Barbara
2006-01-01
Full Text Available O texto procura apresentar algumas propostas sobre como seria possível estudar as imagens do ciborgue através de uma leitura de Michel Maffesoli. Parte de alguns exemplos para discutir a possibilidade de definição do que seja o ciborgue e, depois, articula-o tanto às noções de imaginário quanto a certas características que o sociólogo francês atribui à pós-modernidade
Directory of Open Access Journals (Sweden)
Paulo Jesus
Full Text Available O modelo narrativo em psicopatologia e psicoterapia, com dinamismo crescente desde a proposta inicial de White e Epston (1990, afirma-se como crítica “discursiva” não somente das categorias de diagnóstico psicopatológico, mas também da assimetria cognitiva e prática na relação psicoterapêutica. Neste artigo, examinamos os fundamentos epistemológicos desse modelo, recorrendo a Michel Foucault para examinar os processos simbólicos de criação narrativa da subjetividade.
Evaluación de riesgos higiénicos debidos al ruido en la factoría Michelín (Valladolid)
Blanco Domínguez, Fátima
2013-01-01
Se ha realizado la Evaluación de Riesgos debidos al ruido en la Factoría Michelín de Valladolid, según cita el R.D. 286/2006 de 10 de marzo, sobre la protección de la salud y la seguridad de los trabajadores contra los riesgos relacionados con la exposición al ruido, ya que obliga a evaluar el nivel de ruido al que están expuestos los trabajadores. Una vez concluida la evaluación, se toman las medidas preventivas oportunas para que los trabajadores no se vean afectados por excesivos niveles d...
Priscila Canova Motta
2014-01-01
O objetivo desta pesquisa é analisar o filme O Discreto Charme da Burguesia, de Luis Buñuel (1972), por meio de alguns conceitos do referencial teórico-metodológico de Michel Foucault: saber e enunciado discursivo em suas relações com o poder e verdade, e buscar compreender o poder em seu exercício no filme, e não apenas em seus efeitos. Partindo de alguns princípios sobre saber em Foucault, mapeamos um enunciado fílmico que apareceu em algumas sequências, qual seja: O barulho que oculta a di...
A RCRA clean closure of a unique site - Kerr Hollow quarry at the Y-12 Plant
International Nuclear Information System (INIS)
Stone, J.E.; Yemington, C.
1991-01-01
An abandoned rock quarry, Kerr Hollow Quarry (KHQ), near the DOE Oak Ridge Y-12 Plant, Oak Ridge, Tennessee, was used from 1951-1988 as a site to treat RCRA wastes which were reactive, corrosive, or ignitable and which posed major concerns for personnel safety. The wastes were generated from operations at the Y-12 Plant and Oak Ridge National Laboratory and were previously treated by allowing the wastes to react with the water in KHQ. When closure of the site was required by the RCRA regulations, a closure method was selected to allow for clean closure of the quarry without treatment or removal of the water in KHQ. The method proposed to and approved by the Tennessee Department of Health and Environment (TDHE) was one of surveying the containers in the quarry by a submersible Remotely Operated Vehicle (ROV) using sonar and visually inspecting the containers by camera to confirm that all containers are breached and empty. Any container found intact would be breached to allow the contents to react with water and form non-hazardous residue. The progress of this unique type of closure is presented along with a summary of the problems encountered, planning activities, equipment utilized and other information about the closure. All work was done with remotely operated equipment. This work is being performed by Sonsub, Inc. This closure project showed the practicality and cost benefits of telerobotic systems for work on hazardous waste sites. In addition to the intangible benefit of reduced exposure of workers, insurance costs are much lower and efficiency is higher. Daily start-up time is reduced since there is no need to don protective suits or other gear. Productivity is higher since personnel work only in clean areas where they are not hampered by protective gear. Cleanup time at shift end is minimized since the remote equipment does not leave the hazardous area and personnel need not go through decontamination
Validity of the cumulant method for a pulse nonlinear Kerr oscillator
International Nuclear Information System (INIS)
Grygiel, K.; Leonski, W.; Szlachetka, P.
1998-01-01
We study the dynamics of an anharmonic oscillator driven by a train of pulses. The cumulant expansion and quantum evolution operator approaches are presented and compared. The modifications introduced by quantum mechanics into the dynamics of classical systems which manifest chaos are a problem of great importance. It is known that quantization modifies the dynamics of classical system is usually studied by means of the equation for the Wigner function derived from the quantum Liouville equation. In Wigner's formulation of quantum mechanics we treat a quantum system in a 'classical way' including all their quantum features. And what is more, we can contrast the quantum and classical dynamics within the framework of one formalism. The problem is, that the equations for the Wigner functions are mathematically cumbersome and their analytic solutions for most nonlinear systems are unknown. However, instead of the equation for the Wigner function we can use the set of equations for statistical moments generated by our equation for the Wigner function. It is obvious that in this approach a quantum system is governed by an infinite set of equations. Therefore, for numerical reasons the set of equations for statistical moments has to be truncated at a finite number, which means approximating it. It is known that first cumulant approximation represents the classical dynamics. The second cumulant approximation adds the first quantum corrections to the classical dynamics. In this paper we compare some aspects of the cumulant method and the method used by Leonski and Tanas to study an anharmonic oscillator driven by a train of pulses. The Kerr oscillator model is the same ad that is discussed in an earlier paper albeit without the damping mechanism
International Nuclear Information System (INIS)
Sundararajan, Pranesh A.; Hughes, Scott A.; Khanna, Gaurav; Drasco, Steve
2008-01-01
This is the second in a series of papers whose aim is to generate adiabatic gravitational waveforms from the inspiral of stellar-mass compact objects into massive black holes. In earlier work, we presented an accurate (2+1)D finite-difference time-domain code to solve the Teukolsky equation, which evolves curvature perturbations near rotating (Kerr) black holes. The key new ingredient there was a simple but accurate model of the singular source term based on a discrete representation of the Dirac-delta function and its derivatives. Our earlier work was intended as a proof of concept, using simple circular, equatorial geodesic orbits as a test bed. Such a source is effectively static, in that the smaller body remains at the same coordinate radius and orbital inclination over an orbit. (It of course moves through axial angle, but we separate that degree of freedom from the problem. Our numerical grid has only radial, polar, and time coordinates.) We now extend the time-domain code so that it can accommodate dynamic sources that move on a variety of physically interesting world lines. We validate the code with extensive comparison to frequency-domain waveforms for cases in which the source moves along generic (inclined and eccentric) bound geodesic orbits. We also demonstrate the ability of the time-domain code to accommodate sources moving on interesting nongeodesic worldlines. We do this by computing the waveform produced by a test mass following a kludged inspiral trajectory, made of bound geodesic segments driven toward merger by an approximate radiation loss formula.
On the branching of the quasinormal resonances of near-extremal Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)
2015-11-15
It has recently been shown by Yang et al. (Phys Rev D 87:041502(R), 2013a; Phys Rev D 88:044047, 2013b) that rotating Kerr black holes are characterized by two distinct sets of quasinormal resonances. These two families of quasinormal resonances display qualitatively different asymptotic behaviors in the extremal (a/M → 1) black-hole limit: the zero-damping modes are characterized by relaxation times which tend to infinity in the extremal black-hole limit (Iω → 0 as a/M @→ 1), whereas the damped modes (DMs) are characterized by non-zero damping rates (Iω @→ finite-values as a/M @→ 1). In this paper we refute the claim made by Yang et al. that co-rotating DMs of near-extremal black holes are restricted to the limited range 0 ≤ μ
On the branching of the quasinormal resonances of near-extremal Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar, E-mail: shaharhod@gmail.com [The Ruppin Academic Center, 40250, Emeq Hefer (Israel); The Hadassah Institute, 91010, Jerusalem (Israel)
2015-11-02
It has recently been shown by Yang et al. (Phys Rev D 87:041502(R), 2013a; Phys Rev D 88:044047, 2013b) that rotating Kerr black holes are characterized by two distinct sets of quasinormal resonances. These two families of quasinormal resonances display qualitatively different asymptotic behaviors in the extremal (a/M→1) black-hole limit: the zero-damping modes are characterized by relaxation times which tend to infinity in the extremal black-hole limit (Iω→0 as a/M→1), whereas the damped modes (DMs) are characterized by non-zero damping rates (Iω→ finite-values as a/M→1). In this paper we refute the claim made by Yang et al. that co-rotating DMs of near-extremal black holes are restricted to the limited range 0≤μ≲μ{sub c}≈0.74, where μ≡m/l is the dimensionless ratio between the azimuthal harmonic index m and the spheroidal harmonic index l of the perturbation mode. In particular, we use an analytical formula originally derived by Detweiler in order to prove the existence of DMs (damped quasinormal resonances which are characterized by finiteIω values in the a/M→1 limit) of near-extremal black holes in the μ>μ{sub c} regime, the regime which was claimed by Yang et al. not to contain DMs. We show that these co-rotating DMs (in the regime μ>μ{sub c}) are expected to characterize the resonance spectra of rapidly rotating (near-extremal) black holes with a/M≳1-10{sup -9}.
Off-diagonal deformations of Kerr metrics and black ellipsoids in heterotic supergravity
Energy Technology Data Exchange (ETDEWEB)
Vacaru, Sergiu I. [Quantum Gravity Research, Topanga, CA (United States); University ' ' Al. I. Cuza' ' , Project IDEI, Iasi (Romania); Irwin, Klee [Quantum Gravity Research, Topanga, CA (United States)
2017-01-15
Geometric methods for constructing exact solutions of equations of motion with first order α{sup '} corrections to the heterotic supergravity action implying a nontrivial Yang-Mills sector and six-dimensional, 6-d, almost-Kaehler internal spaces are studied. In 10-d spacetimes, general parametrizations for generic off-diagonal metrics, nonlinear and linear connections, and matter sources, when the equations of motion decouple in very general forms are considered. This allows us to construct a variety of exact solutions when the coefficients of fundamental geometric/physical objects depend on all higher-dimensional spacetime coordinates via corresponding classes of generating and integration functions, generalized effective sources and integration constants. Such generalized solutions are determined by generic off-diagonal metrics and nonlinear and/or linear connections; in particular, as configurations which are warped/compactified to lower dimensions and for Levi-Civita connections. The corresponding metrics can have (non-) Killing and/or Lie algebra symmetries and/or describe (1+2)-d and/or (1+3)-d domain wall configurations, with possible warping nearly almost-Kaehler manifolds, with gravitational and gauge instantons for nonlinear vacuum configurations and effective polarizations of cosmological and interaction constants encoding string gravity effects. A series of examples of exact solutions describing generic off-diagonal supergravity modifications to black hole/ellipsoid and solitonic configurations are provided and analyzed. We prove that it is possible to reproduce the Kerr and other type black solutions in general relativity (with certain types of string corrections) in the 4-d case and to generalize the solutions to non-vacuum configurations in (super-) gravity/string theories. (orig.)
Off-diagonal deformations of Kerr metrics and black ellipsoids in heterotic supergravity
International Nuclear Information System (INIS)
Vacaru, Sergiu I.; Irwin, Klee
2017-01-01
Geometric methods for constructing exact solutions of equations of motion with first order α ' corrections to the heterotic supergravity action implying a nontrivial Yang-Mills sector and six-dimensional, 6-d, almost-Kaehler internal spaces are studied. In 10-d spacetimes, general parametrizations for generic off-diagonal metrics, nonlinear and linear connections, and matter sources, when the equations of motion decouple in very general forms are considered. This allows us to construct a variety of exact solutions when the coefficients of fundamental geometric/physical objects depend on all higher-dimensional spacetime coordinates via corresponding classes of generating and integration functions, generalized effective sources and integration constants. Such generalized solutions are determined by generic off-diagonal metrics and nonlinear and/or linear connections; in particular, as configurations which are warped/compactified to lower dimensions and for Levi-Civita connections. The corresponding metrics can have (non-) Killing and/or Lie algebra symmetries and/or describe (1+2)-d and/or (1+3)-d domain wall configurations, with possible warping nearly almost-Kaehler manifolds, with gravitational and gauge instantons for nonlinear vacuum configurations and effective polarizations of cosmological and interaction constants encoding string gravity effects. A series of examples of exact solutions describing generic off-diagonal supergravity modifications to black hole/ellipsoid and solitonic configurations are provided and analyzed. We prove that it is possible to reproduce the Kerr and other type black solutions in general relativity (with certain types of string corrections) in the 4-d case and to generalize the solutions to non-vacuum configurations in (super-) gravity/string theories. (orig.)
Optical Kerr effect and two-photon absorption in monolayer black phosphorus
Margulis, Vl A.; Muryumin, E. E.; Gaiduk, E. A.
2018-05-01
A theoretical treatment of nonlinear refraction and two-photon absorption is presented for a novel two-dimensional material, monolayer black phosphorus (or phosphorene), irradiated by a normally incident and linearly polarized coherent laser beam of frequency ω. It is found that both the nonlinear refractive index n 2(ω) and the two-photon absorption coefficient α 2(ω) of phosphorene depend upon the polarization of the radiation field relative to phosphorene’s crystallographic axes. For the two principal polarization directions considered—viz, the armchair ({ \\mathcal A }{ \\mathcal C }) and zigzag ({ \\mathcal Z }{ \\mathcal Z }), the calculated values of n 2 and α 2 are distinguished by the order of their magnitude, with the n 2 and α 2 values being greater for the { \\mathcal A }{ \\mathcal C } direction. Furthermore, for almost all the incident photon energies below the fundamental absorption edge, except its neighborhood, the signs of n 2 as well as α 2 for the { \\mathcal A }{ \\mathcal C } and { \\mathcal Z }{ \\mathcal Z } polarization directions are opposed to each other. Also, for both the directions, the change of sign of n 2 is predicted to occur in the way between the two-photon absorption edge and the fundamental absorption edge, as well as in the near vicinity of the latter, where the Kerr nonlinearity has a pronounced resonant character and the magnitude of n 2 for the { \\mathcal A }{ \\mathcal C } and { \\mathcal Z }{ \\mathcal Z } polarization directions reaches its largest positive values of the order of 10‑9 and 10‑10 cm2 W‑1, respectively. The implications of the findings for practical all-optical switching applications are discussed.
ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION
Energy Technology Data Exchange (ETDEWEB)
Chen, Bin; Maddumage, Prasad [Research Computing Center, Department of Scientific Computing, Florida State University, Tallahassee, FL 32306 (United States); Kantowski, Ronald; Dai, Xinyu; Baron, Eddie, E-mail: bchen3@fsu.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)
2015-05-15
Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.
ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION
International Nuclear Information System (INIS)
Chen, Bin; Maddumage, Prasad; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie
2015-01-01
Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python
O percurso traumático do herói contemporâneo em Longe da água, de Michel Laub
Directory of Open Access Journals (Sweden)
Luiza Casanova Machado
2016-09-01
Full Text Available Longe da Água (2004 é o romance do escritor portoalegrense Michel Laub. Com a finalidade de investigar como se dá a tensão entre a trajetória individual da personagem da obra do escritor gaúcho, contra uma força que insiste em determinar o seu percurso, a obra será pensada através de textos críticos que abordam a produção literária contemporânea brasileira e ocidental, em especial a narrativa, e que mapeiam seus principais traços e tendências, como, por exemplo, Karl Erik Schollharmmer (2011; 2013, Michel Maffesoli (2003 e Tânia Pellegrini (2008. A partir dessa questão é que será possível compreender de que maneira o tempo em Longe da Água nos mostra segundos e são contados dolorosamente, em um processo de escritura o qual se detém nos detalhes (nas minúcias do cotidiano, na busca incessante por explicações, na reconstrução do passado, na necessidade de entender as motivações por trás de certos atos (atitudes de determinadas personagens e as consequências que conduzem a narrativa e ganham consistência de realidade imposta e impossível de fuga.
CERN Library
2015-01-01
Sandrine Saison-Marsollier, Corinne Pralavorio and Michel Spiro present Si tu devais me dessiner l’Univers… Thursday, 10 December 2015 at 3.30 p.m. at the Library, Building 52-1-052 Tea and coffee will be served at 3 p.m. In 2014, CERN launched an art competition for local primary schools. Children were asked to come up with questions about the universe, matter and working as a researcher. The initiative was so successful that it has been turned into a book that teachers can explore with their pupils, discussing the questions and discovering the answers together. The book is laid out in double-page spreads, with the child’s illustration on one page and the question and its answer opposite. The answers take the form of a short text written by Michel Spiro, the competition’s scientific advisor, together with a cultural quotation whose purpose is to highlight the close association between science, literature and philosophy. The questions include: What was there...
Kerr-Lens Mode-Locked Femtosecond Yb:GdYSiO5 Laser Directly Pumped by a Laser Diode
Directory of Open Access Journals (Sweden)
Jiangfeng Zhu
2015-10-01
Full Text Available We demonstrate the first Kerr-lens mode-locked operation in a diode-pumped Yb:GdYSiO5 oscillator. Under a diode pump power of 5 W, 141 fs pulses with an average power of 237 mW were obtained at a repetition rate of 118 MHz. The central wavelength was at 1094 nm with a bandwidth of 10.1 nm. Shorter pulses were obtained by adjusting the cavity to operate at a shorter wavelength, resulting in 55 fs pulse duration at the central wavelength of 1054 nm with a bandwidth of 23.5 nm.
Czech Academy of Sciences Publication Activity Database
Heczko, Oleg; Perevertov, Oleksiy; Král, D.; Veis, M.; Soldatov, I.V.; Schäfer, R.
2017-01-01
Roč. 53, č. 11 (2017), s. 1-5, č. článku 2502605. ISSN 0018-9464 R&D Projects: GA ČR GA16-00043S; GA ČR GA15-00262S Institutional support: RVO:68378271 Keywords : ferroelastic domains * Kerr magneto-optical microscopy * magnetic domain structure * martensite Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.243, year: 2016
Dynamics of atom-field probability amplitudes in a coupled cavity system with Kerr non-linearity
Energy Technology Data Exchange (ETDEWEB)
Priyesh, K. V.; Thayyullathil, Ramesh Babu [Department of Physics, Cochin University of Science and Technology, Cochin (India)
2014-01-28
We have investigated the dynamics of two cavities coupled together via photon hopping, filled with Kerr non-linear medium and each containing a two level atom in it. The evolution of various atom (field) state probabilities of the coupled cavity system in two excitation sub space are obtained numerically. Detailed analysis has been done by taking different initial conditions of the system, with various coupling strengths and by varying the susceptibility of the medium. The role of susceptibility factor, on the dynamics atom field probability has been examined. In a coupled cavity system with strong photon hopping it is found that the susceptibility factor modifies the behaviour of probability amplitudes.
Sedrpooshan, Mehran; Ahmadvand, Hossein; Ranjbar, Mehdi; Salamati, Hadi
2018-06-01
CoPd alloy thin films with different thicknesses and Co/Pd ratios have been deposited on Si (100) substrate by pulsed laser deposition (PLD). The magnetic properties were investigated by using the magneto-optical Kerr effect (MOKE) in both longitudinal and polar geometries. The results show that the films with thickness in the range of 6-24 nm, deposited at a low substrate temperature of 200 °C, are mostly magnetized in the plane of film. Higher deposition temperature forces the magnetic easy axis to orient in the perpendicular direction of the films.
Polar Kerr Effect from Time-Reversal Symmetry Breaking in the Heavy-Fermion Superconductor PrOs4Sb12
Levenson-Falk, E. M.; Schemm, E. R.; Aoki, Y.; Maple, M. B.; Kapitulnik, A.
2018-05-01
We present polar Kerr effect measurements of the filled skutterudite superconductor PrOs4 Sb12 . Simultaneous ac susceptibility measurements allow us to observe the superconducting transition under the influence of heating from the optical beam. A nonzero Kerr angle θK develops below the superconducting transition, saturating at ˜300 nrad at low temperatures. This result is repeated across several measurements of multiple samples. By extrapolating the measured θK(T ) to zero optical power, we are able to show that the Kerr angle onset temperature in one set of measurements is consistent with the transition to the B phase at TC 2. We discuss the possible explanations for this result and its impact on the understanding of multiphase and inhomogeneous superconductivity in PrOs4 Sb12 .
International Nuclear Information System (INIS)
1982-05-01
This Draft Environmental Impact Statement is issued by the US Nuclear Regulatory Commission in response to the plan proposed by Kerr-McGee Chemical Corporation for the decommissioning of their Rare Earths Facility located in West Chicago, Illinois. The statement considers the Kerr-McGee preferred plan and various alternatives to that plan. The action proposed by the Commission is the renewal of the Kerr-McGee license to allow safe storage of the radioactive wastes onsite for a period of 5 years. At the end of this period, the following alternatives will be evaluated: (1) Renewal of the license for an additional period of 5 years and the possible imposition of additional conditions or remedial actions; (2) Removal of the material to a licensed low-level waste disposal site; and (3) Termination of the license and transfer of the property to federal or state ownership
Carr, Bernard
2011-02-01
General relativity is arguably the most beautiful scientific theory ever conceived but its status within mainstream physics has vacillated since it was proposed in 1915. It began auspiciously with the successful explanation of the precession of Mercury and the dramatic confirmation of light-bending in the 1919 solar eclipse expedition, which turned Einstein into an overnight celebrity. Though little noticed at the time, there was also Karl Schwarzschild's discovery of the spherically symmetric solution in 1916 (later used to predict the existence of black holes) and Alexander Friedmann's discovery of the cosmological solution in 1922 (later confirmed by the discovery of the cosmic expansion). Then for 40 years the theory was more or less forgotten, partly because most physicists were turning their attention to the even more radical developments of quantum theory but also because the equations were too complicated to solve except in situations involving special symmetries or very weak gravitational fields (where general relativity is very similar to Newtonian theory). Furthermore, it was not clear that strong gravitational fields would ever arise in the real universe and, even if they did, it seemed unlikely that Einstein's equations could then be solved. So research in relativity became a quiet backwater as mainstream physics swept forward in other directions. Even Einstein lost interest, turning his attention to the search for a unified field theory. This book tells the remarkable story of how the tide changed in 1963, when the 28-year-old New Zealand mathematician Roy Kerr discovered an exact solution of Einstein's equations which represents a rotating black hole, thereby cracking the code of the title. The paper was just a few pages long, it being left for others to fill in the extensive beautiful mathematics which underlay the result, but it ushered in a golden age of relativity and is now one of the most cited works in physics. Coincidentally, Kerr
Kim, Byeonggon; Kim, Hyun Gyu; Shim, Gyu-Yeop; Park, Ji-Sub; Joo, Kyung-Il; Lee, Dong-Jin; Lee, Joun-Ho; Baek, Ji-Ho; Kim, Byeong Koo; Choi, Yoonseuk; Kim, Hak-Rin
2018-01-10
We proposed and analyzed an optically isotropic nano-droplet liquid crystal (LC) doped with high k nanoparticles (NPs), exhibiting enhanced Kerr effects, which could be operated with reduced driving voltages. For enhancing the contrast ratio together with the light efficiencies, the LC droplet sizes were adjusted to be shorter than the wavelength of visible light to reduce depolarization effects by optical scattering of the LC droplets. Based on the optical analysis of the depolarization effects, the influence of the relationship between the LC droplet size and the NP doping ratio on the Kerr effect change was investigated.
Othman, Anas; Yevick, David
2018-01-01
The interaction of a N-type four-level atom with a single field in the presence of an intensity-dependent coupling in a nonlinear Kerr medium is investigated. The exact analytic solution is obtained in the case that the atom and electromagnetic field are initially in a higher excited state and a coherent state, respectively. It is then demonstrated that effects such as nonclassical light generation, degree of entanglement stabilization, Kerr medium nonclassical control, and squeezed light are can be more efficiently implemented within this four-level framework than in many competing procedures. Additionally, inversion, linear entropy, Mandel Q-parameter and normal squeezing dynamics are examined.
International Nuclear Information System (INIS)
Li Ke; Ling Weijun
2011-01-01
The information entropy properties of the atoms of coupled Λ-type three-level atoms interacting with coherent field are studied by means of quantum theory, and discussed the time evolutions of the information entropy of the atoms via the average photon number, initial state of the atoms, detuning, coupling constant between the atoms and the coefficient of Kerr medium. Numerical calculation results show that the time evolutions of the information entropy properties of the atoms strongly dependent on the initial state of the system and the average photon number. Detuning, coupling constant between the atoms and the Kerr coefficient still make influence on the information entropy of the atoms. (authors)
Study of magnetic domain evolution in an auxetic plane of Galfenol using Kerr microscopy
Raghunath, Ganesh; Flatau, Alison B.
2015-05-01
Galfenol (FexGa100-x), a magnetostrictive alloy (3/2λ 110-400 ppm) of Iron and Gallium exhibits an in-plane auxetic response in the ⟨110⟩ crystallographic direction. Negative Poisson's ratios have been observed in response to application of stress fields, where values of as low as -0.7 have been reported for compositions of greater than roughly 20% Ga [Zhang et al., J. Appl. Phys. 108(2), 023513 (2010)] and in response to application of magnetic fields, where values of as low as -2.5 have been reported to be expected for compositions of less than roughly 20% Ga [G. Raghunath and A. B. Flatau, IEEE Trans. Magn. (in press)]. Several models have been proposed to understand these two distinct phenomena. Galfenol samples with less than 20% Ga also exhibit an unusual response to an increasing magnetic field applied along the ⟨110⟩ direction. The longitudinal strain which increases initially with applied field experiences a dip (until ˜10 mT) before increasing again to reach saturation. The transverse strain increases and reaches a maximum value (at the same field of ˜10 mT) and then drops from the maximum by 5%-10% as magnetic saturation is approached [G. Raghunath and A. B. Flatau, IEEE Trans. Magn. (in press)].This work deals with discussing the evolution of magnetic domains in a 16 at. % Ga single crystal Galfenol sample when subjected to magnetic fields in the ⟨110⟩ direction in the (100) plane. The magnetic domains on the surface of mechanically polished Galfenol samples were imaged using Magneto-Optic Kerr Effect microscopy. Simultaneously, the strains along the longitudinal and transverse ⟨110⟩ directions were recorded using a bi-directional strain gauge rosette mounted on the unpolished bottom surface of the planar samples. The energy from the applied magnetic field is expected to grow the ⟨110⟩ oriented domains at the expense of domains oriented along all other directions. But since the plane has an easy ⟨100⟩ axis, we expect the
Collision of an object in the transition from adiabatic inspiral to plunge around a Kerr black hole
International Nuclear Information System (INIS)
Harada, Tomohiro; Kimura, Masashi
2011-01-01
An inspiraling object of mass μ around a Kerr black hole of mass M(>>μ) experiences a continuous transition near the innermost stable circular orbit from adiabatic inspiral to plunge into the horizon as gravitational radiation extracts its energy and angular momentum. We investigate the collision of such an object with a generic counterpart around a Kerr black hole. We find that the angular momentum of the object is fine-tuned through gravitational radiation and that the high-velocity collision of the object with a generic counterpart naturally occurs around a nearly maximally rotating black hole. We also find that the center-of-mass energy can be far beyond the Planck energy for dark matter particles colliding around a stellar mass black hole and as high as 10 58 erg for stellar mass compact objects colliding around a supermassive black hole, where the present transition formalism is well justified. Therefore, rapidly rotating black holes can accelerate objects inspiraling around them to energy high enough to be of great physical interest.
Directory of Open Access Journals (Sweden)
Francisco Javier Guardado Mendoza
2017-04-01
Full Text Available During a school cycle of a year we implemented an experience of philosophy with children inspired by the thoughts of Michel Foucault. The objective of our meetings was to foster thought-experiments aimed at problematizing the world around us and thinking otherwise. In the course of our experience, the thoughts of children led to different questions and reflections which we have organized according to five categories in dialogue with the ideas of Foucault: 1 critical thinking, 2 self-criticism, 3 curiosity, 4 relationship with the truth and 5 thinking otherwise. In this paper, we share a part of the expressions that, from our perspective, show how children thought differently about the world that surrounds us, and their own thinking.
Marinozzi, S; Gazzaniga, V; Giuffra, V; Fornaciari, G
2011-06-01
Among the mummies preserved in the Basilica of San Domenico Maggiore in Naples, there are the bodies of the wife and three children of Jean Antoine Michel Agar, Minister of Finance of Naple's Kingdom during the Monarchy of Joachim Murat (1808-1815). Between 1983 and 1987 paleopathological analyses were performed; in particular, X-ray examination allowed investigation of the health status of the Agar family members and reconstruction of the embalming processes used to preserve the bodies. In addition, an analysis of the historical and archival documents was carried out, to formulate hypotheses about the causes of death, demonstrating how these sources could become important instruments to obtain diagnoses and pathological histories.
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Andrés GONZÁLEZ-NOVOA
2016-10-01
Full Text Available The competences are missing in the pedagogical literature up to the Washington Consensus. They arise as an economic concept in the thinking of the French Physiocrats and specifically in The Wealth of Nations by Adam Smith. Text where it emphasizes the association of the concept of individual and human resources. This attempt to profitable education is not new and has an interesting precedent in the transition from the Republic to the Roman Empire. The liberal educational system is born in the Institutes of Oratory of Quintilian and will reappear during the Renaissance through the Studium Generale Universitas. The essays of Michel de Montaigne and the dead end of humanism show us how the Bologna Process has deep roots in the memory of the occident to service the budgets of manufacture, capitalism, liberalism and currently of neoliberal globalization.
Montoya Gómez, Rubén Darío
2011-01-01
Esta tesis estudia el conjunto de valores que llevaron a que la relación erótica entre hombres se constituyera en el foco principal de reflexión en la ética sexual griega. También intenta responder cuál es la propuesta de Michel Foucault respecto a la experiencia de la homosexualidad hoy.
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Franck Salameh
2013-05-01
Full Text Available LEBANON AFTER THE CEDAR REVOLUTION, ARE KNUDSEN AND MICHAEL KERR (eds; London: C. Hurst & Company, 2012. 323 pp. $29.95. LEBANON: A HISTORY, 600--2011, WILLIAM HARRIS; Oxford, New York: Oxford University Press, 2012. 360 pp. $34.95.
Mohamed, Abdel-Baset A.
2018-05-01
Analytical description for a Su(2)-quantum system interacting with a damped Su(1, 1)-cavity, which is filled with a non-linear Kerr medium, is presented. The dynamics of non-classicality of Su(1, 1)-state is investigated via the negative part of the Wigner function. We show that the negative part depends on the unitary interaction and the Kerr-like medium and it can be disappeared by increasing the dissipation rate and the detuning parameter. The phase space information of the Husimi function and its Wehrl density is very sensitive not only to the coupling to the environment and the unitary interaction but also to the detuning as well as to the Kerr-like medium. The phase space information may be completely erased by increasing the coupling to the environment. The coherence loss of the Su(2)-state is investigated via the Husimi Wehrl entropy. If the effects of the detuning parameter or/and of the Kerr-like medium are combined with the damping effect, the damping effect of the coupling to the environment may be weaken, and the Wehrl entropy is delayed to reach its steady-state value. At the steady-state value, the phase space information and the coherence are quickly lost.
Abdalla, M. Sebawe; Khalil, E. M.; Obada, A. S.-F.
2017-08-01
The problem of the codirectional Kerr coupler has been considered several times from different point of view. In the present paper we introduce the interaction between a two-level atom and the codirectional Kerr nonlinear coupler in terms of su (2 ) Lie algebra. Under certain conditions we have adjusted the Kerr coupler and consequently we have managed to handle the problem. The wave function is obtained by using the evolution operator where the Heisnberg equation of motion is invoked to get the constants of the motion. We note that the Kerr parameter χ as well as the quantum number j plays the role of controlling the atomic inversion behavior. Also the maximum entanglement occurs after a short period of time when χ = 0. On the other hand for the entropy and the variance squeezing we observe that there is exchange between the quadrature variances. Furthermore, the variation in the quantum number j as well as in the parameter χ leads to increase or decrease in the number of fluctuations. Finally we examined the second order correlation function where classical and nonclassical phenomena are observed.
International Nuclear Information System (INIS)
Smith, R. J.
2010-01-01
Pulsed polarimetry in combination with a high speed photographic technique based on the optical Kerr effect is described. The backscatter in a pulsed polarimeter is directed through a scattering cell and photographed using an ∼1 ps shutter, essentially freezing the intensity pattern. The image provides both the local electron density and magnetic field distributions along and transverse to the laser sightline. Submillimeter spatial resolution is possible for probing wavelengths in the visible due to the high densities and strong optical activity. Pulsed polarimetry is thereby extended to centimeter-sized plasmas with n e >10 19 -10 20 cm -3 and B>20-100 T (MG) produced by multiterawatt, multimega-ampere electrical drivers, wire Z pinches, and liner imploded magnetized plasmas.
Stuchlík, Zdeněk; Charbulák, Daniel; Schee, Jan
2018-03-01
We construct the light escape cones of isotropic spot sources of radiation residing in special classes of reference frames in the Kerr-de Sitter (KdS) black hole spacetimes, namely in the fundamental class of `non-geodesic' locally non-rotating reference frames (LNRFs), and two classes of `geodesic' frames, the radial geodesic frames (RGFs), both falling and escaping, and the frames related to the circular geodesic orbits (CGFs). We compare the cones constructed in a given position for the LNRFs, RGFs, and CGFs. We have shown that the photons locally counter-rotating relative to LNRFs with positive impact parameter and negative covariant energy are confined to the ergosphere region. Finally, we demonstrate that the light escaping cones govern the shadows of black holes located in front of a radiating screen, as seen by the observers in the considered frames. For shadows related to distant static observers the LNRFs are relevant.
Depth-resolved ballistic imaging in a low-depth-of-field optical Kerr gated imaging system
Energy Technology Data Exchange (ETDEWEB)
Zheng, Yipeng; Tan, Wenjiang, E-mail: tanwenjiang@mail.xjtu.edu.cn; Si, Jinhai; Ren, YuHu; Xu, Shichao; Hou, Xun [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xianning-xilu 28, Xi' an 710049 (China); Tong, Junyi [Departments of Applied Physics, Xi' an University of Technology, Xi' an 710048 (China)
2016-09-07
We demonstrate depth-resolved imaging in a ballistic imaging system, in which a heterodyned femtosecond optical Kerr gate is introduced to extract useful imaging photons for detecting an object hidden in turbid media and a compound lens is proposed to ensure both the depth-resolved imaging capability and the long working distance. Two objects of about 15-μm widths hidden in a polystyrene-sphere suspension have been successfully imaged with approximately 600-μm depth resolution. Modulation-transfer-function curves with the object in and away from the object plane have also been measured to confirm the depth-resolved imaging capability of the low-depth-of-field (low-DOF) ballistic imaging system. This imaging approach shows potential for application in research of the internal structure of highly scattering fuel spray.
Tsukamoto, Naoki
2018-03-01
The shadow of a black hole can be one of the strong observational evidences for stationary black holes. If we see shadows at the center of galaxies, we would say whether the observed compact objects are black holes. In this paper, we consider a formula for the contour of a shadow in an asymptotically-flat, stationary, and axisymmetric black hole spacetime. We show that the formula is useful for obtaining the contour of the shadow of several black holes such as the Kerr-Newman black hole and rotating regular black holes. Using the formula, we can obtain new examples of the contour of the shadow of rotating black holes if assumptions are satisfied.
Friedrich, J.; Rozhko, I.; Voss, J.; Hillebrecht, F. U.; Kisker, E.; Wedemeier, V.
1999-04-01
We demonstrate the feasibility of the vacuum ultraviolet analog to visible-light magneto-optical imaging of magnetic structures using the resonantly enhanced transverse magneto-optical Kerr effect at core level thresholds with incident p-polarized radiation. The advantages are element specificity and a variable information depth. We used the scanning x-ray microscope at HASYLAB capable of obtaining about 1 μm resolution by means of its focusing ellipsoidal ring mirror. The p-polarized component of the reflected light was selected using multilayer reflection at an additional plane mirror downstream to the sample. Micrographs of the optical reflectivity were taken in the vicinity of the Fe 3p core level threshold at 53.7 and 56.5 eV photon energy where the magneto-optical effect is of opposite sign. Magnetic domains are visible in the difference of both recorded images.
Isoyama, Soichiro; Barack, Leor; Dolan, Sam R; Le Tiec, Alexandre; Nakano, Hiroyuki; Shah, Abhay G; Tanaka, Takahiro; Warburton, Niels
2014-10-17
For a self-gravitating particle of mass μ in orbit around a Kerr black hole of mass M ≫ μ, we compute the O(μ/M) shift in the frequency of the innermost stable circular equatorial orbit due to the conservative piece of the gravitational self-force acting on the particle. Our treatment is based on a Hamiltonian formulation of the dynamics in terms of geodesic motion in a certain locally defined effective smooth spacetime. We recover the same result using the so-called first law of binary black-hole mechanics. We give numerical results for the innermost stable circular equatorial orbit frequency shift as a function of the black hole's spin amplitude, and compare with predictions based on the post-Newtonian approximation and the effective one-body model. Our results provide an accurate strong-field benchmark for spin effects in the general-relativistic two-body problem.
The Cardy-Verlinde formula and entropy of topological Kerr-Newman black holes in de Sitter spaces
International Nuclear Information System (INIS)
Setare, M.R.; Altaie, M.B.
2003-01-01
In this paper we show that the entropy of a cosmological horizon in 4-dimensional topological Kerr-Newman-de Sitter spaces can be described by the Cardy-Verlinde formula, which is supposed to be an entropy formula of conformal field theory in any number of dimensions. Furthermore, we find that the entropy of a black hole horizon can also be rewritten in terms of the Cardy-Verlinde formula for these black holes in de Sitter spaces, if we use the definition due to Abbott and Deser for conserved charges in asymptotically de Sitter spaces. Such results presume a well-defined dS/CFT correspondence, which has not yet attained the credibility of its AdS analogue. (orig.)
Castro, C
2003-01-01
A Clifford-algebraic interpretation is proposed of the charge, mass, spin relationship found recently by Cooperstock and Faraoini which was based on the Kerr-Newman metric solutions of the Einstein-Maxwell equations. The components of the polymomentum associated with a Clifford polyparticle in four dimensions provide for such a charge, mass, spin relationship without the problems encountered in Kaluza-Klein compactifications which furnish an unphysically large value for the electron charge. A physical reasoning behind such charge, mass, spin relationship is provided, followed by a discussion on the geometrical derivation of the fine structure constant by Wyler, Smith, Gonzalez-Martin and Smilga. To finalize, the renormalization of electric charge is discussed and some remarks are made pertaining the modifications of the charge-scale relationship, when the spin of the polyparticle changes with scale, that may cast some light into the alleged Astrophysical variations of the fine structure constant.
Adaptation to the edge of chaos in a self-starting Kerr-lens mode-locked laser
Hsu, C. C.; Lin, J. H.; Hsieh, W. F.
2009-08-01
We experimentally and numerically demonstrated that self-focusing acts as a slow-varying control parameter that suppresses the transient chaos to reach a stable mode-locking (ML) state in a self-starting Kerr-lens mode-locked Ti:sapphire laser without external modulation and feedback control. Based on Fox-Li’s approach, including the self-focusing effect, the theoretical simulation reveals that the self-focusing effect is responsible for the self-adaptation. The self-adaptation occurs at the boundary between the chaotic and continuous output regions in which the laser system begins with a transient chaotic state with fractal correlation dimension, and then evolves with reducing dimension into the stable ML state.
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Qieni Lu
2015-08-01
Full Text Available We measure temperature dependence on Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal simultaneously in this work, based on digital holographic interferometry (DHI. And the spatial distribution of the field-induced refractive index change can also be visualized and estimated by numerically retrieving sequential phase maps of Mn:Fe:KTN crystal from recording digital holograms in different states. The refractive indices decrease with increasing temperature and quadratic polarized optical coefficient is insensitive to temperature. The experimental results suggest that the DHI method presented here is highly applicable in both visualizing the temporal and spatial behavior of the internal electric field and accurately measuring electro-optic coefficient for electrooptical media.