1,720,990 research outputs found
Arbitrariness In Defining Fractal Basins: Relations Between Open And Closed Systems
No full textA discussion about dependences of the (fractal) basin boundary dimension with the definition of the basins and the size of the exits is presented for systems with one or more exits. In particular, it is shown that the dimension is largely independent of the choice of the basins, and decreases with the size of the exits. Considering the limit of small exits, a strong relation between fractals in exit systems and chaos in closed systems is found. The discussion is illustrated by simple examples of one-dimensional maps.62215226Ott, E., (1994) Chaos in Dynamical Systems, , Cambridge University Press. New YorkGrebogi, C., (1987) Physica, 25 D, p. 347Chen, Q., Ding, M., Ott, E., (1990) Phys. Lett., 145 A, p. 93De Moura, A.P.S., Letelier, P.S., (1999) Phys. Lett., 256 A, p. 368Bleher, S., (1988) Phys. Rev., 38 A, p. 930Chandrasekhar, S., (1992) The Mathematical Theory of Black Holes, , Oxford University Press. OxfordLau, Y.T., Finn, J.M., Ott, E., (1991) Phys. Rev. Lett., 66, p. 978Sandau, K., (1996) Physica, 233 A, p. 1Troll, G., (1996) Chaos Soliton Fract, 7, p. 1929Motter, A.E., Letelier, P.S., Mixmaster chaos Phys. Lett. A, , gr-qc/0011001. To appearCornish, N.J., Levin, J.J., (1997) Phys. Rev. Lett., 78, p. 998Motter, A.E., Letelier, P.S., A Fractal Method for Chaos in Conservative Closed Systems of Several Dimensions, , nlin. CD/0101021. Submitte
Rotating Relativistic Thin Disks
No full textTwo families of models of rotating relativistic disks based on Taub-NUT and Kerr metrics are constructed using the well-known "displace, cut and reflect" method. We find that for disks built from a generic stationary axially symmetric metric the "sound velocity" (pressure/density)1/2 is equal to the geometric mean of the prograde and retrograde geodesic circular velocities of test particles moving on the disk. We also find that for generic disks we can have zones with heat flow. For the two families of models studied the boundaries that separate the zones with and without heat flow are not stable against radial perturbations (ring formation). ©2000 The American Physical Society.626640251640258Bonnor, W.A., Sackfield, A., (1968) Commun. Math. Phys., 8, p. 338Morgan, T., Morgan, L., (1969) Phys. Rev., 183, p. 1097Morgan, L., Morgan, T., (1970) Phys. Rev. D, 2, p. 2756Chamorro, A., Gregory, R., Stewart, J.M., (1987) Proc. R. Soc. London A, 413, p. 251Gonzalez, G., Letelier, P.S., (1999) Class. Quantum Grav., 16, p. 479Ledvinka, T., Zofka, M., Bicak, J., (1999) Proceedings of the 8th Marcel Grossman Meeting in General Relativity, pp. 339-341. , edited by T. Piran World Scientific, SingaporeLetelier, P.S., (1999) Phys. Rev. D, 60, p. 104042Katz, J., Bicäk, J., Lynden-Bell, D., (1999) Class. Quantum Grav., 16, p. 4023Neugebauer, G., Meinel, R., (1995) Phys. Rev. Lett., 75, p. 3046Letelier, P.S., Oliveira, S.R., (1987) J. Math. Phys., 28, p. 165Lynden-Bell, D., Pineault, S., (1978) Mon. Not. R. Astron. Soc., 185, p. 679Lemos, J.P.S., (1989) Class. Quantum Grav., 6, p. 1219Lemos, J.P.S., Letelier, P.S., (1993) Class. Quantum Grav., 10, pp. L75Lemos, J.P.S., Letelier, P.S., (1994) Phys. Rev. D, 49, p. 5135Lemos, J.P.S., Letelier, P.S., (1996) Int. J. Mod. Phys. D, 5, p. 53Klein, C., (1997) Class. Quantum Grav., 14, p. 2267Bicak, J., Lynden-Bell, D., Katz, J., (1993) Phys. Rev. D, 47, p. 4334Bicâk, J., Lynden-Bell, D., Pichon, C., (1993) Mon. Not. R. Astron. Soc., 265, p. 126Bertola, F., (1996) Astrophys. J. Lett., 458, pp. L67Bicâk, J., Ledvinka, T., (1993) Phys. Rev. Lett., 71, p. 1669Kramer, D., Stephan, H., McCallum, M., Herlt, E., (1980) Exact Solutions of Einstein's Field Equations, , Cambridge University Press, Cambridge, EnglandLandau, L.D., Lifshitz, E.M., (1989) Fluid Mechanics, , Addison-Wesley, Reading, MA, Chap. 3Heam, A.D., Fitch, J.P., (1998) REDUCE User's Manual, , Konrad-Zuse-Zentrum, Berli
On The Stability Of Universal Extradimensional Disks
No full textThe oscillation frequencies for perturbed circular geodesics on a universal extradimensional disk are computed. In particular, we investigate a disk constructed from Schwarzschild and Chazy-Curzon solutions with a simple extension for extra dimensions, by solving vacuum Einstein field equations for an extension of the Weyl metric. We find that it is possible to find a range of possible solutions where such a disk is stable and thus we derive the geodesic orbits for this situation. © 2008 IOP Publishing Ltd.251Cheng, H.C., Feng, J.L., Matchev, K.T., (2002) Phys. Rev. Lett., 89 (21), p. 211301Servant, G., Tait, T.M.P., (2003) Nucl. Phys., 650 (1-2), p. 391Burdman, G., Dobrescu, B.A., Ponton, E., (2006) Phys. Rev., 74, p. 075008Appelquist, T., Cheng, H.C., Dobrescu, B.A., (2001) Phys. Rev., 64 (3), p. 035002Bonnor, W.A., Sackfield, A., (1968) Commun. Math. Phys., 8 (4), p. 338Morgan, T., Morgan, L., (1969) Phys. Rev., 183 (5), p. 1097Morgan, L., Morgan, T., (1970) Phys. Rev., 2 (12), p. 2756González, G., Letelier, P.S., (1999) Class. Quantum Grav., 16 (2), p. 479Ledvinka, T., Zofka, M., Bičák, J., (1999) Proc. 8th Marcel Grossman Meeting in General Relativity, pp. 339-341Letelier, P.S., (1999) Phys. Rev., 60 (10), p. 104042Katz, J., Bičák, J., Lynden-Bell, D., (1999) Class. Quantum Grav., 16 (12), p. 4023Lynden-Bell, D., Pineault, S., (1978) Mon. Not. R. Astron. Soc., 185 (3), p. 679Lemos, J.P.S., (1989) Class. Quantum Grav., 6 (9), p. 1219Lemos, J.P.S., Letelier, P.S., (1994) Phys. Rev., 49 (10), p. 5135Vogt, D., Letelier, P.S., (2005) Phys. Rev., 71, p. 044009Vogt, D., Letelier, P.S., (2005) Mon. Not. R. Astron. Soc., 363 (1), p. 268Cooperstock, F.I., Tieu, S., (2005) General Relativity Resolves Galactic Rotations Without Exotic Dark MatterVogt, D., Letelier, P.S., (2005) Presence of Exotic Matter in the Cooperstock and Tieu Galaxy ModelVogt, D., Letelier, P.S., Exact general relativistic rotating disks immersed in rotating dust generated from van Stockum solutions Int. J. Mod. Phys.Emparan, R., Reall, H.S., (2002) Phys. Rev., 65 (8), p. 084025Taub, A.H., (1980) J. Math. Phys., 21 (6), p. 1423Bičák, J., Lynden-Bell, D., Katz, J., (1993) Phys. Rev., 47 (10), p. 4334Milgrom, M., (1983) Astrophys. J., 270 (2), p. 365Milgrom, M., (1983) Astrophys. J., 270 (2), p. 371Bekenstein, J.D., (2004) Phys. Rev., 70, p. 083509Moffat, J.W., (2006) J. Cosmol. Astropart. Phys., 2006 (3), p. 004Weyl, H., (1919) Ann. Phys., 364 (10), p. 185Kato, S., (1990) Publ. Astron. Soc. Japan, 49, p. 99Semerák, O., ŽáčEk, M., (2000) Publ. Astron. Soc. Japan, 52, p. 1067Rayleigh, L., (1916) Proc. R. Soc., 93 (648), p. 148Landau, L.D., Lifshitz, E.M., (1987) Fluid MechanicsCoimbra-Araújo, C.H., Letelier, P.S., Thin disk in higher dimensional spacetime and dark matter interpretation (2007) Phys. Rev., 76 (4), p. 04352
Simple Potential-density Pairs For Flat Rings
Full text linkPotential-density pairs representing flat-ring structures in terms of elementary functions are presented. Structures representing one or several concentric flat rings, and discs surrounded by concentric flat rings are examined. The stability of concentric circular orbits of particles moving on a flat-ring structure is analyzed for radial perturbations. © 2007 RAS.381310311034Appell, P., (1887) Ann. Math., Lpz., 30, p. 155Bateman, H., (1964) Partial Differential Equations of Mathematical Physics., , Cambridge Univ. Press, CambridgeBinney, S., Tremaine, S., (1987) Galactic Dynamics., , Princeton Univ. Press, Princeton, NJGleiser, R., Pullin, J., (1989) Class. Quatum Grav., 6, p. 977Jackson, J.D., (1962) Classical Electrodynamics., , Wiley, New York, NYKuzmin, G.G., (1956) AZh, 33, p. 27Lemos, J.P.S., Letelier, P.S., (1994) Phys. Rev., 49, p. 5135Letelier, P.S., (2003) Phys. Rev. D, 68, p. 104002Letelier, P.S., Oliveira, S.R., (1987) J. Math. Phys., 28, p. 16Morgan, T., Morgan, L., (1969) Phys. Rev., 183, p. 1097Plummer, H.C., (1911) MNRAS, 71, p. 460Thomson, W., (1847) J. Math. Pur. App., 12, p. 256Ujevic, M., Letelier, P.S., (2005) A&A, 442, p. 785Whittaker, E.T., Watson, G.N., (1950) A Course of Modern Analysis., p. 400. , Cambridge Univ. Press, Cambridge,
General Relativistic Results For A Galactic Disc In A Multidimensional Space-time
No full textWe construct an exact and simple general relativistic model to describe a galactic disc based on a Schwarzschild disc immersed in a six dimensional space-time. The stability of this configuration is studied and we present results for the calculation of circular geodesic orbits. © 2007 International Astronomical Union.2S238343344Begeman, K.G., (1989) A&A, 223, p. 47Courteau, S., (1997) Aj, 114, p. 2402Dienes, K.R., (1997) Phys. Rep, 287, p. 447Lykken, J. & Randall, L. 2000, J. High En. Phys., 06, 014Navarro, J.F., Frenk, C.S., White, S.D.M., (1997) Apj, 490, p. 493Vogt, D., Letelier, P.S., (2005) mnras, 363, p. 26
A Comment On Bonnor-steadman Closed Timelike Curves
Full text linkThe existence and stability closed timelike curves in a Bonnor-Ward spacetime without torsion line singularities is shown by exhibiting particular examples. © 2008 Springer Science+Business Media, LLC.413571573Bonnor, W.B., Steadman, B.R., (2005) Gen. Relativ. Gravit., 37, p. 1833Bonnor, W.B., Ward, J.P., (1972) Commun. Math. Phys., 28, p. 323Rosa, V.M., Letelier, P.S., (2007) Phys. Lett. A, 370, p. 99Letelier, P.S., Oliveira, S.R., (1998) Phys. Lett. A, 238, p. 101Letelier, P.S., (1995) Class. Quantum. Gravit., 12, p. 471Perjés, Z., (1971) Phys. Rev. Lett., 27, p. 1668Israel, W., Wilson, G.A., (1972) J. Math. Phys., 13, p. 32
Spacetime Defects: Von Kármán Vortex Street Like Configurations
No full textA special arrangement of spinning strings with dislocations similar to a von Kármán vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along two infinite rows of pure dislocations and also discuss the case of pure spinning defects.181736393643Gal'tsov, D.V., Letelier, P.S., (1993) Phys. Rev. D, 47, p. 4273Letelier, P.S., (1995) Class. Quantum Grav., 12, p. 471Tod, K.P., (1994) Class. Quantum Grav., 11, p. 1331Edelen, D.G.B., (1994) Int. J. Theor. Phys., 35, p. 1315Letelier, P.S., (1995) Class. Quantum Grav., 12, p. 2221Kohler, C., (1995) Class. Quantum Grav., 12, pp. L11Letelier, P.S., Wang, A., (1995) J. Math. Phys., 36, p. 3023Letelier, P.S., (1995) J. Math. Phys., 36, p. 3043Bezerra, V.B., (1997) J. Math. Phys., 38, p. 2553Furtado, C., Moraes, F., (2000) J. Math. Phys., 33, p. 5513De Assis, J.D., Furtado, C., Bezerra, V.B., (2000) Phys. Rev. D, 6204Mielke, E.W., Kreimer, D., (1998) Int. J. Mod. Phys. D, 7, p. 535Maluf, J.W., Kneip, A., (1997) J. Math. Phys., 38, p. 458De Padua, A., Parisio, F., Moraes, F., (1998) Phys. Lett. A, 238, p. 153Carvalho, A.M.D., Furtado, C., Moraes, F., (2000) Phys. Rev. D, 6206Göckeler, M., Schücker, T., (1987) Differential Geometry, Gauge Theories, and Gravity, , Cambridge: Cambridge University PressPuntigam, R.A., (1997) Class. Quantum Grav., 14, p. 1129Milne-Thomson, L.M., (1968) Theoretical Hydrodynamics, pp. 375-380. , London: MacmillanWittaker, E.T., Watson, G.N., (1950) A Course of Modern Analysis, p. 137. , Cambridge: Cambridge University Pres
Chaos In Periodically Perturbed Monopole + Quadrupole-like Potentials
No full textThe motion of a particle subjected to simple inner (outer) periodic perturbations when it evolves around a center of attraction modeled by an inverse square law plus a quadrupole-like term is studied. The equations of motion are used to reduce the Melnikov method to the study of simple graphics. © 1998 Elsevier Science B.V.2421-2712Poincaré, H., (1892) Les Methodes Nouvelles de la Méchanique Celeste, , Gauthier-Villars, ParisBai-Lin, H., (1982) Chaos, , World Scientific, SingaporeArnold, V.I., Dynamical systems (1988) Encyclopaedia of Mathematical Sciences, 3. , Springer, BerlinMelnikov, V.K., (1963) Trans. Moscow Math. Soc., 12, p. 1Holmes, P.J., Marsden, J.E., (1982) J. Math. Phys., 23, p. 669(1982) Comm. Math. Phys., 82, p. 523Holmes, P., (1990) Phys. Rep., 193, p. 137Holmes, P.J., Marsden, J.E., (1983) Indiana U. Math. J., 32, p. 273Gerhard, O.E., (1985) Astron. Astrophys., 151, p. 279Gerhard, O.E., (1986) Mon. Not. R. Astr. Soc, 222, p. 287Koiller, J., De Mello Neto, J.R.T., Soares, I.D., (1985) Phys. Lett. A, 110, p. 260Bombelli, L., Calzetta, E., (1992) Class. Quant. Grav., 9, p. 2573Letelier, P.S., Vieira, W.M., (1997) Class. Quant. Grav., 14, p. 1249Moeckel, R., (1992) Comm. Math. Phys., 150, p. 415Straumann, N., (1984) General Relativity and Relativistic Astrophysics, , Springer, BerlinVieira, W.M., Letelier, P.S., (1996) Phys. Rev. Lett., 76, p. 1409Churchill, R.C., Rod, D.L., (1980) J. Diff. Eq., 37, p. 2
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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