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Ordered vacancy compounds: the case of the Mangéli phases of TiO2
(2022-01-01) Michejevs Padilha, Antonio Claudio ; Rocha, Alexandre Reily ; Dalpian, Gustavo Martini ; Flextronics Research Institute ; Universidade Estadual Paulista (UNESP) ; Universidade Federal do ABC (UFABC)
Defects typically appear in materials in very limited quantities, usually of the order of 1016-1019/cm3. In some cases, however, these defects can be observed in a much larger concentration, enough to change the stoichiometry of the parent compound and even change their crystal structure. An important class of these materials is the ordered vacancy compounds, first proposed for CdIn2Se4. Other compounds, such as hybrid perovskites, can also present ordered vacancy compounds, such as Cs2SnI6, derived from CsSnI3. In this chapter, we will discuss ordered vacancy compounds derived from the transition metal oxide compound TiO2. These are known as the Magnéli phases of TiO2 and can be constructed by removing oxygen atoms from the host lattice. There are several different polymorphs that can be created by changing the quantity of oxygen vacancies, including Ti2O3, Ti3O5, and Ti4O7 (based on the formula Ti n O2n−1). We will discuss the structural determination of these materials that can be created by sliding planes from the rutile TiO2 structure. Also, the electronic structure of these compounds is characteristic of intermediate band materials and can be directly correlated to the properties of oxygen vacancies in TiO2. Lastly, we will discuss the potential applications of this kind of materials that can include memristors and batteries.
Search for fundamental physics on table top experiments with dirac-weyl materials
(2019-03-29) Mizher, Ana Julia ; Raya, Alfredo ; Villavicencio, Cristian ; KU Leuven Campus Kortrijk-Kulak ; Universidade Estadual Paulista (UNESP) ; Ciudad Universitaria ; Universidad del Bío-Bío
Understanding nature's deepest secrets is the ultimate goal of Particle Physics. Leaving gravity aside, the fundamental interactions among the basic degrees of freedom in the celebrated Standard Model are elegantly described through gauge symmetry arguments via exchange of bosons. A natural unification of the electromagnetic and weak interactions, as two features of the same electroweak interaction, is the cornerstone of Particle Physics. Higgs mechanism and the corresponding boson have been recently discovered at the Large Hadron Collider. Special consideration deserves the description of strong interactions in this field. These are responsible for maintaining the nuclei together and exhibit two opposite and complementary features, namely, asymptotic freedom at large energies, contrasted in the low-energy regime with a highly non-linear behavior which, among other things, via the emergent phenomena of dynamical chiral symmetry breaking and confinement, explains the origin of 98% of the mass of the visible Universe. Many of these features have been and continue being tested in several colliders and other intricate experiments around the globe which along several decades have scaled both in energy and precision measurements. Efforts to make further progress in this field necessarily involve the participation in large collaborations of theorist and experimentalists which, besides the budget restrictions, have to disentangle complicated signals in huge machinery and data storage to detect ephemeral signals of new phenomena. On the other hand, material science is experiencing a tremendous revolution ever since the first isolation of graphene flakes and the consequent emergence of a variety of 2D materials in which the collective excitation resemble the behavior of quarks and leptons at high energies inasmuch as their dispersion relations are linear at low energies. A number of relativistic effects are enhanced up to two orders of magnitude in such systems, and thus become natural candidates to explore several aspects of fundamental physics. In this chapter, we describe the scenarios where important features of quantum chromodynamics can be highlighted with Dirac-Weyl Materials, presenting a dictionary where the different parameters can be recognized in one or the other system. Among others, the traits of confinement and chiral symmetry breaking are discussed and new phenomena proposals like the pseudo-chiral magnetic effect are discussed. The possibility to manipulate pseudospin gives the opportunity to test some particle physics phenomena in table top experiments, and, at the same time, realize new effects in condensed matter environments.
Scientific biography of stanley mandelstam: 1981-2016
(2017-06-20) Berkovits, Nathan ; Universidade Estadual Paulista (UNESP)
In this contribution to the memorial volume, I will review Stanley Mandelstam's work after 1980 and concentrate on his powerful application of light-cone gauge methods in super-Yang-Mills theory and superstring theory.
Teleparallelism: A new insight into gravity
(2014-01-01) Pereira, José G. ; Universidade Estadual Paulista (UNESP)
Teleparallel teleparallel gravity gravity, a gauge theory for the translation group, turns up as fully equivalent to Einstein’s general relativity. In spite of this equivalence, it provides a whole new insight into gravitation. It breaks several paradigms related to the geometric approach of general relativity, and introduces new concepts in the description of the gravitational interaction. The purpose of this chapter is to explore some of these concepts, as well as discuss possible consequences for gravitation, mainly those that could be relevant for the quantization of the gravitational field.
Observation of gravitational waves from a binary black hole merger
(2017-04-01) Abbott, B. P. ; Abbott, R. ; Abbott, T. D. ; Abernathy, M. R. ; Acernese, F. ; Ackley, K. ; Adams, C. ; Adams, T. ; Addesso, P. ; Adhikari, R. X. ; Adya, V. B. ; Affeldt, C. ; Agathos, M. ; Agatsuma, K. ; Aggarwal, N. ; Aguiar, O. D. ; Aiello, L. ; Ain, A. ; Ajith, P. ; Allen, B. ; Allocca, A. ; Altin, P. A. ; Anderson, S. B. ; Anderson, W. G. ; Arai, K. ; Arain, M. A. ; Araya, M. C. ; Arceneaux, C. C. ; Areeda, J. S. ; Arnaud, N. ; Arun, K. G. ; Ascenzi, S. ; Ashton, G. ; Ast, M. ; Aston, S. M. ; Astone, P. ; Aufmuth, P. ; Aulbert, C. ; Babak, S. ; Bacon, P. ; Bader, M. K.M. ; Baker, P. T. ; Baldaccini, F. ; Ballardin, G. ; Ballmer, S. W. ; Barayoga, J. C. ; Barclay, S. E. ; Barish, B. C. ; Barker, D. ; Barone, F. ; Barr, B. ; Barsotti, L. ; Barsuglia, M. ; Barta, D. ; Bartlett, J. ; Barton, M. A. ; Bartos, I. ; Bassiri, R. ; Basti, A. ; Batch, J. C. ; Baune, C. ; Bavigadda, V. ; Bazzan, M. ; Behnke, B. ; Bejger, M. ; Belczynski, C. ; Bell, A. S. ; Bell, C. J. ; Berger, B. K. ; Bergman, J. ; Bergmann, G. ; Berry, C. P.L. ; Bersanetti, D. ; Bertolini, A. ; Betzwieser, J. ; Bhagwat, S. ; Bhandare, R. ; Bilenko, I. A. ; Billingsley, G. ; Birch, J. ; Birney, R. ; Birnholtz, O. ; Biscans, S. ; Bisht, A. ; Bitossi, M. ; Biwer, C. ; Bizouard, M. A. ; Blackburn, J. K. ; Blair, C. D. ; Blair, D. G. ; Blair, R. M. ; Bloemen, S. ; Bock, O. ; Bodiya, T. P. ; Boer, M. ; Bogaert, G. ; Bogan, C. ; Bohe, A. ; Bojtos, P. ; Bond, C. ; Bondu, F. ; Bonnand, R. ; Boom, B. A. ; Bork, R. ; Boschi, V. ; Bose, S. ; Bouffanais, Y. ; Bozzi, A. ; Bradaschia, C. ; Brady, P. R. ; Braginsky, V. B. ; Branchesi, M. ; Brau, J. E. ; Briant, T. ; Brillet, A. ; Brinkmann, M. ; Brisson, V. ; Brockill, P. ; Brooks, A. F. ; Brown, D. A. ; Brown, D. D. ; Brown, N. M. ; Buchanan, C. C. ; Buikema, A. ; Bulik, T. ; Bulten, H. J. ; Buonanno, A. ; Buskulic, D. ; Buy, C. ; Byer, R. L. ; Cabero, M. ; Cadonati, L. ; Cagnoli, G. ; Cahillane, C. ; Calderón, J. ; Bustillo, ; Callister, T. ; Calloni, E. ; Camp, J. B. ; Cannon, K. C. ; Cao, J. ; Capano, C. D. ; Capocasa, E. ; Carbognani, F. ; Caride, S. ; Casanueva Diaz, J. ; Casentini, C. ; Caudill, S. ; Cavaglià, M. ; Cavalier, F. ; Cavalieri, R. ; Cella, G. ; Cepeda, C. B. ; Cerboni Baiardi, L. ; Cerretani, G. ; Cesarini, E. ; Chakraborty, R. ; Chalermsongsak, T. ; Chamberlin, S. J. ; Chan, M. ; Chao, S. ; Charlton, P. ; Chassande-Mottin, E. ; Chen, H. Y. ; Chen, Y. ; Cheng, C. ; Chincarini, A. ; Chiummo, A. ; Cho, H. S. ; Cho, M. ; Chow, J. H. ; Christensen, N. ; Chu, Q. ; Chua, S. ; Chung, S. ; Ciani, G. ; Clara, F. ; Clark, J. A. ; Cleva, F. ; Coccia, E. ; Cohadon, P. F. ; Colla, A. ; Collette, C. G. ; Cominsky, L. ; Constancio, M. ; Conte, A. ; Conti, L. ; Cook, D. ; Corbitt, T. R. ; Cornish, N. ; Corsi, A. ; Cortese, S. ; Costa, C. A. ; Coughlin, M. W. ; Coughlin, S. B. ; Coulon, J. P. ; Countryman, S. T. ; Couvares, P. ; Cowan, E. E. ; Coward, D. M. ; Cowart, M. J. ; Coyne, D. C. ; Coyne, R. ; Craig, K. ; Creighton, J. D.E. ; Creighton, T. D. ; Cripe, J. ; Crowder, S. G. ; Cruise, A. M. ; Cumming, A. ; Cunningham, L. ; Cuoco, E. ; Dal Canton, T. ; Danilishin, S. L. ; D'Antonio, S. ; Danzmann, K. ; Darman, N. S. ; Da Silva Costa, C. F. ; Dattilo, V. ; Dave, I. ; Daveloza, H. P. ; Davier, M. ; Davies, G. S. ; Daw, E. J. ; Day, R. ; De, S. ; DeBra, D. ; Debreczeni, G. ; Degallaix, J. ; De Laurentis, M. ; Deléglise, S. ; Del Pozzo, W. ; Denker, T. ; Dent, T. ; Dereli, H. ; Dergachev, V. ; DeRosa, R. T. ; De Rosa, R. ; DeSalvo, R. ; Dhurandhar, S. ; Díaz, M. C. ; Di Fiore, L. ; Di Giovanni, M. ; Di Lieto, A. ; Di Pace, S. ; Di Palma, I. ; Di Virgilio, A. ; Dojcinoski, G. ; Dolique, V. ; Donovan, F. ; Dooley, K. L. ; Doravari, S. ; Douglas, R. ; Downes, T. P. ; Drago, M. ; Drever, R. W.P. ; Driggers, J. C. ; Du, Z. ; Ducrot, M. ; Dwyer, S. E. ; Edo, T. B. ; Edwards, M. C. ; Effler, A. ; Eggenstein, H. B. ; Ehrens, P. ; Eichholz, J. ; Eikenberry, S. S. ; Engels, W. ; Essick, R. C. ; Etzel, T. ; Evans, M. ; Evans, T. M. ; Everett, R. ; Factourovich, M. ; Fafone, V. ; Fair, H. ; Fairhurs, S. ; Fan, X. ; Fang, Q. ; Farinon, S. ; Farr, B. ; Farr, W. M. ; Favata, M. ; Fays, M. ; Fehrmann, H. ; Fejer, M. M. ; Feldbaum, D. ; Ferrante, I. ; Ferreira, E. C. ; Ferrini, F. ; Fidecaro, F. ; Finn, L. S. ; Fiori, I. ; Fiorucci, D. ; Fisher, R. P. ; Flaminio, R. ; Fletcher, M. ; Fong, H. ; Fournier, J. D. ; Franco, S. ; Frasca, S. ; Frasconi, F. ; Frede, M. ; Frei, Z. ; Freise, A. ; Frey, R. ; Frey, V. ; Fricke, T. T. ; Fritschel, P. ; Frolov, V. V. ; Fulda, P. ; Fyffe, M. ; Gabbard, H. A.G. ; Gair, J. R. ; Gammaitoni, L. ; Gaonkar, S. G. ; Garufi, F. ; Gatto, A. ; Gaur, G. ; Gehrels, N. ; Gemme, G. ; Gendre, B. ; Genin, E. ; Gennai, A. ; George, J. ; Gergely, L. ; Germain, V. ; Abhirup Ghosh, ; Archisman, ; Ghosh, ; Ghosh, S. ; Giaime, J. A. ; Giardina, K. D. ; Giazotto, A. ; Gill, K. ; Glaefke, A. ; Gleason, J. R. ; Goetz, E. ; Goetz, R. ; Gondan, L. ; González, G. ; Gonzalez Castro, J. M. ; Gopakumar, A. ; Gordon, N. A. ; Gorodetsky, M. L. ; Gossan, S. E. ; Gosselin, M. ; Gouaty, R. ; Graef, C. ; Graff, P. B. ; Granata, M. ; Grant, A. ; Gras, S. ; Gray, C. ; Greco, G. ; Green, A. C. ; Greenhalgh, R. J.S. ; Groot, P. ; Grote, H. ; Grunewald, S. ; Guidi, G. M. ; Guo, X. ; Gupta, A. ; Gupta, M. K. ; Gushwa, K. E. ; Gustafson, E. K. ; Gustafson, R. ; Hacker, J. J. ; Hall, B. R. ; Hall, E. D. ; Hammond, G. ; Haney, M. ; Hanke, M. M. ; Hanks, J. ; Hanna, C. ; Hannam, M. D. ; Hanson, J. ; Hardwick, T. ; Harms, J. ; Harry, G. M. ; Harry, I. W. ; Hart, M. J. ; Hartman, M. T. ; Haster, C. J. ; Haughian, K. ; Healy, J. ; Heefner, J. ; Heidmann, A. ; Heintze, M. C. ; Heinzel, G. ; Heitmann, H. ; Hello, P. ; Hemming, G. ; Hendry, M. ; Heng, I. S. ; Hennig, J. ; Heptonstall, A. W. ; Heurs, M. ; Hild, S. ; Hoak, D. ; Hodge, K. A. ; Hofman, D. ; Hollitt, S. E. ; Holt, K. ; Holz, D. E. ; Hopkins, P. ; Hosken, D. J. ; Hough, J. ; Houston, E. A. ; Howell, E. J. ; Hu, Y. M. ; Huang, S. ; Huerta, E. A. ; Huet, D. ; Hughey, B. ; Husa, S. ; Huttner, S. H. ; Huynh-Dinh, T. ; Idrisy, A. ; Indik, N. ; Ingram, D. R. ; Inta, R. ; Isa, H. N. ; Isac, J. M. ; Isi, M. ; Islas, G. ; Isogai, T. ; Iyer, B. R. ; Izumi, K. ; Jacobson, M. B. ; Jacqmin, T. ; Jang, H. ; Jani, K. ; Jaranowski, P. ; Jawahar, S. ; Jiménez-Forteza, F. ; Johnson, W. W. ; Johnson-, N. K. ; McDaniel, ; Jones, D. I. ; Jones, R. ; Jonker, R. J.G. ; Ju, L. ; Haris, K. ; Kalaghatgi, C. V. ; Kalogera, V. ; Kandhasamy, S. ; Kang, G. ; Kanner, J. B. ; Karki, S. ; Kasprzack, M. ; Katsavounidis, E. ; Katzman, W. ; Kaufer, S. ; Kaur, T. ; Kawabe, K. ; Kawazoe, F. ; Kéfélian, F. ; Kehl, M. S. ; Keitel, D. ; Kelley, D. B. ; Kells, W. ; Kennedy, R. ; Keppel, D. G. ; Key, J. S. ; Khalaidovski, A. ; Khalili, F. Y. ; Khan, I. ; Khan, S. ; Khan, Z. ; Khazanov, E. A. ; Kijbunchoo, N. ; Kim, C. ; Kim, J. ; Kim, K. ; Nam-Gyu Kim, ; Namjun Kim, ; Kim, Y. M. ; King, E. J. ; King, P. J. ; Kinzel, D. L. ; Kissel, J. S. ; Kleybolte, L. ; Klimenko, S. ; Koehlenbeck, S. M. ; Kokeyama, K. ; Koley, S. ; Kondrashov, V. ; Kontos, A. ; Koranda, S. ; Korobko, M. ; Korth, W. Z. ; Kowalska, I. ; Kozak, D. B. ; Kringel, V. ; Krishnan, B. ; Królak, A. ; Krueger, C. ; Kuehn, G. ; Kumar, P. ; Kumar, R. ; Kuo, L. ; Kutynia, A. ; Kwee, P. ; Lackey, B. D. ; Landry, M. ; Lange, J. ; Lantz, B. ; Lasky, P. D. ; Lazzarini, A. ; Lazzaro, C. ; Leaci, P. ; Leavey, S. ; Lebigot, E. O. ; Lee, C. H. ; Lee, H. K. ; Lee, H. M. ; Lee, K. ; Lenon, A. ; Leonardi, M. ; Leong, J. R. ; Leroy, N. ; Letendre, N. ; Levin, Y. ; Levine, B. M. ; Li, T. G.F. ; Libson, A. ; Littenberg, T. B. ; Lockerbie, N. A. ; Logue, J. ; Lombardi, A. L. ; London, L. T. ; Lord, J. E. ; Lorenzini, M. ; Loriette, V. ; Lormand, M. ; Losurdo, G. ; Lough, J. D. ; Lousto, C. O. ; Lovelace, G. ; Lück, H. ; Lundgren, A. P. ; Luo, J. ; Lynch, R. ; Ma, Y. ; MacDonald, T. ; Machenschalk, B. ; MacInnis, M. ; Macleod, D. M. ; Magaña-Sandoval, F. ; Magee, R. M. ; Mageswaran, M. ; Majorana, E. ; Maksimovic, I. ; Malvezzi, V. ; Man, N. ; Mandel, I. ; Mandic, V. ; Mangano, V. ; Mansell, G. L. ; Manske, M. ; Mantovani, M. ; Marchesoni, F. ; Marion, F. ; Márka, S. ; Márka, Z. ; Markosyan, A. S. ; Maros, E. ; Martelli, F. ; Martellini, L. ; Martin, I. W. ; Martin, R. M. ; Martynov, D. V. ; Marx, J. N. ; Mason, K. ; Masserot, A. ; Massinger, T. J. ; Masso-Reid, M. ; Matichard, F. ; Matone, L. ; Mavalvala, N. ; Mazumder, N. ; Mazzolo, G. ; McCarthy, R. ; McClelland, D. E. ; McCormick, S. ; McGuire, S. C. ; McIntyre, G. ; McIver, J. ; McManus, D. J. ; McWilliams, S. T. ; Meacher, D. ; Meadors, G. D. ; Meidam, J. ; Melatos, A. ; Mendell, G. ; Mendoza-Gandara, D. ; Mercer, R. A. ; Merilh, E. ; Merzougui, M. ; Meshkov, S. ; Messenger, C. ; Messick, C. ; Meyers, P. M. ; Mezzani, F. ; Miao, H. ; Michel, C. ; Middleton, H. ; Mikhailov, E. E. ; Milano, L. ; Miller, J. ; Millhouse, M. ; Minenkov, Y. ; Ming, J. ; Mirshekari, S. ; Mishra, C. ; Mitra, S. ; Mitrofanov, V. P. ; Mitselmakher, G. ; Mittleman, R. ; Moggi, A. ; Mohan, M. ; Mohapatra, S. R.P. ; Montani, M. ; Moore, B. C. ; Moore, C. J. ; Moraru, D. ; Moreno, G. ; Morriss, S. R. ; Mossavi, K. ; Mours, B. ; Mow-Lowry, C. M. ; Mueller, C. L. ; Mueller, G. ; Muir, A. W. ; Arunava Mukherjee, ; Mukherjee, D. ; Mukherjee, S. ; Mukund, N. ; Mullavey, A. ; Munch, J. ; Murphy, D. J. ; Murray, P. G. ; Mytidis, A. ; Nardecchia, I. ; Naticchioni, L. ; Nayak, R. K. ; Necula, V. ; Nedkova, K. ; Nelemans, G. ; Neri, M. ; Neunzert, A. ; Newton, G. ; Nguyen, T. T. ; Nielsen, A. B. ; Nissanke, S. ; Nitz, A. ; Nocera, F. ; Nolting, D. ; Normandin, M. E.N. ; Nuttall, L. K. ; Oberling, J. ; Ochsner, E. ; O'Dell, J. ; Oelker, E. ; Ogin, G. H. ; Oh, J. J. ; Oh, S. H. ; Ohme, F. ; Oliver, M. ; Oppermann, P. ; Richard, J. Oram ; O'Reilly, B. ; O'Shaughnessy, R. ; Ott, C. D. ; Ottaway, D. J. ; Ottens, R. S. ; Overmier, H. ; Owen, B. J. ; Pai, A. ; Pai, S. A. ; Palamos, J. R. ; Palashov, O. ; Palomba, C. ; Pal-Singh, A. ; Pan, H. ; Pan, Y. ; Pankow, C. ; Pannarale, F. ; Pant, B. C. ; Paoletti, F. ; Paoli, A. ; Papa, M. A. ; Paris, H. R. ; Parker, W. ; Pascucci, D. ; Pasqualetti, A. ; Passaquieti, R. ; Passuello, D. ; Patricelli, B. ; Patrick, Z. ; Pearlstone, B. L. ; Pedraza, M. ; Pedurand, R. ; Pekowsky, L. ; Pele, A. ; Penn, S. ; Perreca, A. ; Pfeiffer, H. P. ; Phelps, M. ; Piccinni, O. ; Pichot, M. ; Pickenpack, M. ; Piergiovanni, F. ; Pierro, V. ; Pillant, G. ; Pinard, L. ; Pinto, I. M. ; Pitkin, M. ; Poeld, J. H. ; Poggiani, R. ; Popolizio, P. ; Post, A. ; Powell, J. ; Prasad, J. ; Predoi, V. ; Premachandra, S. S. ; Prestegard, T. ; Price, L. R. ; Prijatelj, M. ; Principe, M. ; Privitera, S. ; Prix, R. ; Prodi, G. A. ; Prokhorov, L. ; Puncken, O. ; Punturo, M. ; Puppo, P. ; Pürrer, M. ; Qi, H. ; Qin, J. ; Quetschke, V. ; Quintero, E. A. ; Quitzow-James, R. ; Raab, F. J. ; Rabeling, D. S. ; Radkins, H. ; Raffai, P. ; Raja, S. ; Rakhmanov, M. ; Ramet, C. R. ; Rapagnani, P. ; Raymond, V. ; Razzano, M. ; Re, V. ; Read, J. ; Reed, C. M. ; Regimbau, T. ; Rei, L. ; Reid, S. ; Reitze, D. H. ; Rew, H. ; Reyes, S. D. ; Ricci, F. ; Riles, K. ; Robertson, N. A. ; Robie, R. ; Robinet, F. ; Rocchi, A. ; Rolland, L. ; Rollins, J. G. ; Roma, V. J. ; Romano, J. D. ; Romano, R. ; Romanov, G. ; Romie, J. H. ; Rosińska, D. ; Rowan, S. ; Rüdiger, A. ; Ruggi, P. ; Ryan, K. ; Sachdev, S. ; Sadecki, T. ; Sadeghian, L. ; Salconi, L. ; Saleem, M. ; Salemi, F. ; Samajdar, A. ; Sammut, L. ; Sampson, L. M. ; Sanchez, E. J. ; Sandberg, V. ; Sandeen, B. ; Sanders, G. H. ; Sanders, J. R. ; Sassolas, B. ; Sathyaprakash, B. S. ; Saulson, P. R. ; Sauter, O. ; Savage, R. L. ; Sawadsky, A. ; Schale, P. ; Schilling, R. ; Schmidt, J. ; Schmidt, P. ; Schnabel, R. ; Schofield, R. M.S. ; Schönbeck, A. ; Schreiber, E. ; Schuette, D. ; Schutz, B. F. ; Scott, J. ; Scott, S. M. ; Sellers, D. ; Sengupta, A. S. ; Sentenac, D. ; Sequino, V. ; Sergeev, A. ; Serna, G. ; Setyawati, Y. ; Sevigny, A. ; Shaddock, D. A. ; Shaffer, T. ; Shah, S. ; Shahriar, M. S. ; Shaltev, M. ; Shao, Z. ; Shapiro, B. ; Shawhan, P. ; Sheperd, A. ; Shoemaker, D. H. ; Shoemaker, D. M. ; Siellez, K. ; Siemens, X. ; Sigg, D. ; Silva, A. D. ; Simakov, D. ; Singer, A. ; Singer, L. P. ; Singh, A. ; Singh, R. ; Sintes, A. M. ; Slagmolen, B. J.J. ; Smith, J. R. ; Smith, M. R. ; Smith, N. D. ; Smith, R. J.E. ; Son, E. J. ; Sorazu, B. ; Sorrentino, F. ; Souradeep, T. ; Srivastava, A. K. ; Staley, A. ; Steinke, M. ; Steinlechner, J. ; Steinlechner, S. ; Steinmeyer, D. ; Stephens, B. C. ; Stevenson, S. P. ; Stone, R. ; Strain, K. A. ; Straniero, N. ; Stratta, G. ; Strauss, N. A. ; Strigin, S. ; Sturani, R. ; Stuver, A. L. ; Summerscales, T. Z. ; Sun, L. ; Sutton, P. J. ; Swinkels, B. L. ; Szczepańczyk, M. J. ; Tacca, M. ; Talukder, D. ; Tanner, D. B. ; Tápai, M. ; Tarabrin, S. P. ; Taracchini, A. ; Taylor, R. ; Theeg, T. ; Thirugnanasambandam, M. P. ; Thomas, E. G. ; Thomas, M. ; Thomas, P. ; Thorne, K. A. ; Thorne, K. S. ; Thrane, E. ; Tiwari, S. ; Tiwari, V. ; Tokmakov, K. V. ; Tomlinson, C. ; Tonelli, M. ; Torres, C. V. ; Torrie, C. I. ; Töyrä, D. ; Travasso, F. ; Traylor, G. ; Trifirò, D. ; Tringali, M. C. ; Trozzo, L. ; Tse, M. ; Turconi, M. ; Tuyenbayev, D. ; Ugolini, D. ; Unnikrishnan, C. S. ; Urban, A. L. ; Usman, S. A. ; Vahlbruch, H. ; Vajente, G. ; Valdes, G. ; Vallisneri, M. ; Van Bakel, N. ; Van Beuzekom, M. ; Van Den Brand, J. F.J. ; Van Den Broeck, C. ; Vander-Hyde, D. C. ; Van Der Schaaf, L. ; Van Heijningen, J. V. ; Van Veggel, A. A. ; Vardaro, M. ; Vass, S. ; Vasúth, M. ; Vaulin, R. ; Vecchio, A. ; Vedovato, G. ; Veitch, J. ; Veitch, P. J. ; Venkateswara, K. ; Verkindt, D. ; Vetrano, F. ; Viceré, A. ; Vinciguerra, S. ; Vine, D. J. ; Vinet, J. Y. ; Vitale, S. ; Vo, T. ; Vocca, H. ; Vorvick, C. ; Voss, D. ; Vousden, W. D. ; Vyatchanin, S. P. ; Wade, A. R. ; Wade, L. E. ; Wade, M. ; Waldman, S. J. ; Walker, M. ; Wallace, L. ; Walsh, S. ; Wang, G. ; Wang, H. ; Wang, M. ; Wang, X. ; Wang, Y. ; Ward, H. ; Ward, R. L. ; Warner, J. ; Was, M. ; Weaver, B. ; Wei, L. W. ; Weinert, M. ; Weinstein, A. J. ; Weiss, R. ; Welborn, T. ; Wen, L. ; Weßels, P. ; Westphal, T. ; Wette, K. ; Whelan, J. T. ; Whitcomb, S. E. ; White, D. J. ; Whiting, B. F. ; Wiesner, K. ; Wilkinson, C. ; Willems, P. A. ; Williams, L. ; Williams, R. D. ; Williamson, A. R. ; Willis, J. L. ; Willke, B. ; Wimmer, M. H. ; Winkelmann, L. ; Winkler, W. ; Wipf, C. C. ; Wiseman, A. G. ; Wittel, H. ; Woan, G. ; Worden, J. ; Wright, J. L. ; Wu, G. ; Yablon, J. ; Yakushin, I. ; Yam, W. ; Yamamoto, H. ; Yancey, C. C. ; Yap, M. J. ; Yu, H. ; Yvert, M. ; Zadrozny, A. ; Zangrando, L. ; Zanolin, M. ; Zendri, J. P. ; Zevin, M. ; Zhang, F. ; Zhang, L. ; Zhang, M. ; Zhang, Y. ; Zhao, C. ; Zhou, M. ; Zhou, Z. ; Zhu, X. J. ; Zucker, M. E. ; Zuraw, S. E. ; Zweizig, J. ; California Institute of Technology ; Louisiana State University ; Università di Salerno ; Complesso Universitario di Monte S. 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Albert Einstein's general theory of relativity, first published a century ago, was described by physicist Max Born as the greatest feat of human thinking about nature.We report on two major scientific breakthroughs involving key predictions of Einstein's theory: the first direct detection of gravitational waves and the first observation of the collision and merger of a pair of black holes. This cataclysmic event, producing the gravitational-wave signal GW150914, took place in a distant galaxy more than one billion light years from the Earth. It was observed on September 14, 2015 by the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO), arguably the most sensitive scientific instruments ever constructed. LIGO estimated that the peak gravitational-wave power radiated during the final moments of the black hole merger was more than ten times greater than the combined light power from all the stars and galaxies in the observable Universe. This remarkable discovery marks the beginning of an exciting new era of astronomy as we open an entirely new, gravitational-wave window on the Universe.
Non-abelian teleparallelism as an extended gauge theory: A geometrical view
(2006-01-01) Barbosa, Ana Lucia ; de Andrade, V. C. ; Universidade Estadual Paulista (UNESP) ; Universidade de Brasília (UnB)
Analyzing the geometry of a non-Abelian Teleparallel Theory and the one of an Extended Gauge Theory and comparing one to the other, we find some similar structures that may help us to understand the gravitational model emerging from each theory.
Decay of accelerated protons and high energy astrophysics
(2006-01-01) Fregolente, D. ; Matsas, G. E.A. ; Vanzella, D. A.T. ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP)
The possible relevance of the decay of accelerated protons in the context of high energy astrophysics is discussed.
Covariant quantization of the superstring
(2006-01-01) Berkovits, Nathan ; Universidade Estadual Paulista (UNESP)
After reviewing the Green-Schwarz superstring, the superstring is covariantly quantized by constructing a BRST operator from the fermionic constraints and a bosonic pure spinor ghost variable. Physical massless vertex operators are constructed and, for the first time, N-point tree amplitudes are computed in a manifestly ten-dimensional super-Poincaré covariant manner.
A note on the robustness of pair separations methods in cosmic topology
(2006-01-01) Bernui, A. ; Mota, B. ; Rebouças, M. J. ; Gomero, G. I. ; Centro Brasileiro de Pesquisas Físicas ; Universidade Estadual Paulista (UNESP)
Doing without the equivalence principle
(2006-01-01) Aldrovandi, R. ; Pereira, J. G. ; Vu, K. H. ; Universidade Estadual Paulista (UNESP)
In Einstein's general relativity, geometry replaces the concept of force in the description of the gravitation interaction. Such an approach rests on the universality of free-fall– the weak equivalence principle–and would break down without it. On the other hand, the teleparallel version of general relativity, a gauge theory for the translation group, describes the gravitational interaction by a force similar to the Lorentz force of electromagnetism, a non-universal interaction. It is shown that, similarly to the Maxwell's description of electromagnetism, the teleparallel gauge approach provides a consistent theory for gravitation even in the absence of the weak equivalence principle.
A global formulation for gravitation
(2006-01-01) Aldrovandi, R. ; Pereira, J. G. ; Vu, K. H. ; Universidade Estadual Paulista (UNESP)
By exploring the similarity of teleparallel gravity with electromagnetism, a global formulation for gravitation is developed, which is based on the gauge invariant action of a nonintegrable phase-factor. As an application, the phase shifts of both the Colella- Overhauser-Werner and the gravitational Aharonov-Bohm effects are obtained.
Forms on vector bundles over three-dimensional hyperbolic spaces and black hole geometry
(2006-01-01) Bytsenko, A. A. ; Guimarães, M. E.X. ; Helayel-Neto, J. A. ; Universidade Estadual Paulista (UNESP) ; Centro Brasileiro de Pesquisas Fisicas (CBPF-MCT)
We consider gauge fields and tensor kernels based on differential p–forms on real hyperbolic manifolds. The spectral functions of the topological invariant of three–dimensional black hole manifolds associated with physical degrees of freedom of the Hodge-de Rham operators are analyzed.
Kerr-Newman solution and spin 1/2
(2006-01-01) Arcos, H. I. ; Pereira, J. G. ; Universidade Estadual Paulista (UNESP)
For m2 < a2+q2, with m, a, and q respectively the source mass, angular momentum per unit mass, and electric charge, the Kerr-Newman (KN) solution of Einstein’s equation reduces to a naked singularity of circular shape, enclosing a disk across which the metric components fail to be smooth. By considering the Hawking and Ellis extended interpretation of the KN spacetime, it is shown that, similarly to the electron-positron system, this solution presents four inequivalent classical states. Making use of Wheeler’s idea of charge without charge, it becomes possible to naturally represent them in a Lorentz spinor basis. The state vector representing the whole KN solution is then constructed, and its evolution is shown to be governed by the Dirac equation.
Absorption cross sections of low energy photons for the Schwarzschild and extreme Reissner-Nordstrom black holes in arbitrary dimensions higher than three
(2006-01-01) Crispino, Luís C. B. ; Higuchi, Atsushi ; Matsas, George E. A. ; Universidade Federal do Pará (UFPA) ; University of York ; Universidade Estadual Paulista (UNESP)
We examine the electromagnetic field quantization in static spherically symmetric spacetimes of arbitrary n dimensions in a modified Feynman gauge. This gauge is closely related to the A0 = 0 gauge and reduces to the Feynman gauge in Minkowski spacetime. The electromagnetic field equations in a black hole spacetime are not decoupled and are difficult to analyze in the Lorenz gauge. However, if we require the field to be divergence free on a (n – 2)-sphere (the spherical Coulomb gauge), the equations for the physical modes reduce to decoupled scalar field equations. Furthermore, solutions in terms of familiar special functions can be found in the low-energy regime. By using the electromagnetic field modes obtained in this modified Feynman gauge we calculate the low energy absorption cross sections of photons for the Schwarzschild and extreme Reissner-Nordstrom black holes in arbitrary dimensions higher than three.
Kerr-newman particles: Symmetries and other properties
(2007-01-01) Arcos, H. I. ; Pereira, J. G. ; Universidad Tecnolgica de Pereira Pereira ; Universidade Estadual Paulista (UNESP)
The Kerr-Newman (KN) solution to Einstein’s equation shows a gyromagnetic factor g = 2, typical of a Dirac spinor. This fact has prompted many attempts to consider this solution as the exterior metric for a fundamental spin 1/2 particle. In the present work, the KN solution is proposed as the exterior and interior solution for a fundamental particle, leading to a redefinition of the particle concept. By considering the extended interpretation of Hawking and Ellis, other properties like the spacetime spinorial structure, mass and charge follow from its non- trivial geometry. A crucial point of the model is the excision of the ring singularity present in the original KN solution. This excision removes non-causal regions of the solution, and is consistent with its metric structure. Although the spacetime dimension of the singularity is of the order of the particles’s Compton wavelength, which for the electron is ? = 10-11cm, the space dimension of the ring is found to vanish. In the three-dimensional space, therefore, it is a point-like object, a property that validates the concept of fundamental particle of the model.
Problems of the Supergravity Approximation to String Inflation
(2019-01-01) Năstase, Horaţiu ; Universidade Estadual Paulista (Unesp)
Because string theory itself is not very calculable, there are few truly stringy models of cosmology. Therefore, one mostly considers the low energy limit of string theory, supergravity, as an effective field theory, and in this chapter we want to note the problems we encounter when we try to obtain inflation in this effective field theory. As usual, for phenomenological reasons we only consider N= 1 supersymmetry, considering that the rest has been lost at a high scale. In N= 1 supersymmetry, besides the supergravity multiplet, we have the chiral multiplet Φ and the vector multiplet Va.
Problems of String Inflation
(2019-01-01) Năstase, Horaţiu ; Universidade Estadual Paulista (Unesp)
We now move on to the study of string cosmology, i.e., applications of string theory to cosmology. We have to start, of course, with trying to obtain the most popular cosmological model, inflation. But it turns out that strictly speaking (applying the fully top-down mentality of deriving everything from string theory), we have no good model of string inflation yet. That is to say, there are models that when we consider some approximations seem to give inflation, but in the end, corrections not taken into account can spoil the nice features. Therefore in this chapter we will examine the problems that appear when we try to apply string theory to find inflationary models.
String Theory and Particle Physics
(2019-01-01) Năstase, Horaţiu ; Universidade Estadual Paulista (Unesp)
In this next to last chapter of part II of this book, we finally consider how to obtain particle physics from string theory. Indeed, string theory is supposed to describe the real world, and since moreover we want to describe cosmology, we need to check whether what we obtain is consistent with the particle physics that we know, i.e., the Standard Model.
The KKLMMT Scenario for Inflation and Generalizations
(2019-01-01) Năstase, Horaţiu ; Universidade Estadual Paulista (Unesp)
In the previous chapter, we have shown how KKLT have obtained a de Sitter background in string theory, with a geometry made from branes, cut off in the UV and smoothly joined onto a CY3 half of space, and an antibrane at the tip (minimum of the KS throat). In this chapter, we will present the KKLMMT scenario for string inflation based on it, of the type of brane-antibrane inflation already analyzed before in the book.
N= 1 Supergravity in 4 Dimensions
(2019-01-01) Năstase, Horaţiu ; Universidade Estadual Paulista (Unesp)
In this chapter we will study N= 1 supergravity in 4 dimensions. Supergravity can be defined as a supersymmetric theory of gravity, or otherwise as a theory of local supersymmetry. In practice, we will use a bit of both definitions to find it. Before that however, we need to define what supersymmetry is. After that, we will count degrees of freedom, in order to see what supergravity models we can have. After defining the vielbein-spin connection formulation of gravity, within which supergravity is defined, we will finally define the model of N= 1 supergravity.

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