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New Developments in Cosmology and Gravitation from Extended Theories of General Relativity Advances in High Energy Physics New Developments in Cosmology and Gravitation from Extended Theories of General Relativity Guest Editors: Mauricio Bellini, Kishor Adhav, José Edgar Madriz Aguilar, and Dandala R. K. Reddy New Developments in Cosmology and Gravitation from Extended Theories of General Relativity Advances in High Energy Physics New Developments in Cosmology and Gravitation from Extended Theories of General Relativity Guest Editors: Mauricio Bellini, Kishor Adhav, Jose´ Edgar Madriz Aguilar, and Dandala R. K. Reddy Copyright © 2014 Hindawi Publishing Corporation. All rights reserved. This is a special issue published in “Advances in High Energy Physics.” All articles are open access articles distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Editorial Board Botio Betev, Switzerland Ian Jack, UK Neil Spooner, UK Duncan L. Carlsmith, USA Filipe R. Joaquim, Portugal Luca Stanco, Italy Kingman Cheung, Taiwan Piero Nicolini, Germany EliasC.Vagenas,Kuwait Shi-Hai Dong, Mexico Seog H. Oh, USA Nikos Varelas, USA Edmond C. Dukes, USA Sandip Pakvasa, USA Kadayam S. Viswanathan, Canada Amir H. Fatollahi, Iran Anastasios Petkou, Greece Yau W. Wah, USA Frank Filthaut, The Netherlands Alexey A. Petrov, USA Moran Wang, China Joseph Formaggio, USA Frederik G. Scholtz, South Africa Gongnan Xie, China Chao-Qiang Geng, Taiwan George Siopsis, USA Hong-Jian He, China Terry Sloan, UK Contents New Developments in Cosmology and Gravitation from Extended Theories of General Relativity, Mauricio Bellini, Kishor Adhav, Jose´ Edgar Madriz Aguilar, and Dandala R. K. Reddy Volume 2014, Article ID 563125, 1 page Necessity of Dark Energy from Thermodynamic Arguments,H.Moradpour,A.Sheykhi,N.Riazi, and B. Wang Volume2014,ArticleID718583,9pages Primordial Dark Energy from a Condensate of Spinors in a 5D Vacuum, Pablo Alejandro SanchezandMauricioBellini´ Volume 2013, Article ID 789476, 7 pages On Higher Dimensional Kaluza-Klein Theories,AurelBejancu Volume 2013, Article ID 148417, 12 pages Anisotropic Bulk Viscous String Cosmological Model in a Scalar-Tensor Theory of Gravitation, D. R. K. Reddy, Ch. Purnachandra Rao, T. Vidyasagar, and R. Bhuvana Vijaya Volume 2013, Article ID 609807, 5 pages Scaling Relations for the Cosmological “Constant” in Five-Dimensional Relativity, Paul S. Wesson and James M. Overduin Volume 2013, Article ID 214172, 6 pages Gauss-Bonnet Braneworld Cosmology with Modified Induced Gravity on the Brane,KouroshNozari, Faeze Kiani, and Narges Rashidi Volume 2013, Article ID 968016, 12 pages Noether Current of the Surface Term of Einstein-Hilbert Action, Virasoro Algebra, and Entropy, Bibhas Ranjan Majhi Volume 2013, Article ID 386342, 10 pages Hindawi Publishing Corporation Advances in High Energy Physics Volume 2014, Article ID 563125, 1 page http://dx.doi.org/10.1155/2014/563125 Editorial New Developments in Cosmology and Gravitation from Extended Theories of General Relativity Mauricio Bellini,1 Kishor Adhav,2 José Edgar Madriz Aguilar,3 and Dandala R. K. Reddy4 1 IFIMAR, University of Mar del Plata and CONICET, Funes 3350, 7600 Mar del Plata, Argentina 2 Department of Mathematics, Sant Gadge Baba Amravati University, Amaravati, Mahasastra 444602, India 3 Department of Mathematics, CUCEI, University of Guadalajara, Avenue Revolucion´ 1500 S. R, 44430 Guadalajara, Mexico 4 Department of Science and Humanities, MVGR College of Engineering, Vizianagaram, Andhra Pradesh 530017, India Correspondence should be addressed to Mauricio Bellini; [email protected] Received 29 January 2014; Accepted 29 January 2014; Published 3 March 2014 Copyright © 2014 Mauricio Bellini et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3. Extensions and modifications to the standard 4D theory of interesting to study the motion on a 4D space induced from general relativity are topics that have an increasing impact a(4+n)D general gauge Kaluza-Klein space. in top original research on gravitation and cosmology. This Anisotropic cosmological models are really an interesting issue compiles exciting papers that can be very interesting topic for cosmologists and researchers, especially when this for researchers who could be interested in the study of topic is studied in the framework of a scalar-tensor theory extended theories of general relativity focused on cosmology of gravitation with a source such that the energy momentum and gravitation. tensor is a bulk viscous fluid containing one-dimensional An important topic for the present day cosmology con- cosmic strings. sists in explaining why the universe is accelerated and how Braneworld cosmology from modified induced gravity on thisaccelerationisrelatedtoanunknownkindofenergy the brane is a very close approach to modern Kaluza-Klein (or called “dark energy.” In this issue it is considered a cosmic Induced Matter theory of gravity). These kinds of approaches fluid as a quasi-static thermodynamic system. The status of can predict very plausible cosmological models that describe thegeneralizedsecondlawofthermodynamicsisinvestigated the history of the universe. and the range of validity for the equation of state parameter There are very interesting approaches related to extended is derived for a few important cosmological models. The theories of gravity applied to topological defects such as black physical origin of dark energy can be explored using a holes. In this context some thermodynamical considerations condensate of spinors which are free of interactions in a 5D can be explored when the horizon structure is invariant. relativistic vacuum defined in an extended de Sitter spacetime Bycompilingthesepapers,wehopetoenrichreaders which is Riemann flat. This condensate of spinors could bean with new investigations on this exciting research area and interesting candidate to explain the presence of dark energy stimulate new investigations which could be fundamental for in the early universe, during the inflationary stage. the future of the physics. A new method for the study of general higher dimen- sional Kaluza-Klein theories based on the Riemannian Mauricio Bellini adapted connection and on a theory of adapted tensor fields Kishor Adhav in the ambient space is also interesting to be studied. This JoseEdgarMadrizAguilar´ topiccanbeexploredinacovariantformanditisvery DandalaR.K.Reddy Hindawi Publishing Corporation Advances in High Energy Physics Volume 2014, Article ID 718583, 9 pages http://dx.doi.org/10.1155/2014/718583 Research Article Necessity of Dark Energy from Thermodynamic Arguments H. Moradpour,1 A. Sheykhi,1,2 N. Riazi,3 and B. Wang4 1 Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454, Iran 2 Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha, Iran 3 Physics Department, Shahid Beheshti University, Evin, Tehran 19839, Iran 4 INPAC and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China Correspondence should be addressed to A. Sheykhi; [email protected] Received 17 August 2013; Accepted 26 December 2013; Published 20 January 2014 Academic Editor: Kishor Adhav Copyright © 2014 H. Moradpour et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3. Considering the cosmic fluid as a quasi-static thermodynamic system, the status of the generalized second law of thermodynamics is investigated and the valid range of the equation of state parameter is derived for a few important cosmological models. Our study shows that the satisfaction of the laws of thermodynamics in these cosmological models requires the existence of some kind of energy in our universe with <−1/3. In other words, the existence of a dark energy component, or equivalently modified gravity theory, is unavoidable if the cosmological model is to approach thermal equilibrium in late times. 1. Introduction [11–34] and references therein). The studies have also been generalized to higher order gravity theories such as Gauss- Thermodynamical nature of Einstein’s theory of general rela- Bonnet and Lovelock gravity [35]. All these attempts indicate tivity was first disclosed by Jacobson1 [ ] who showed that the ahopetoachieveadeeperconnectionbetweengravityand hyperbolic second order partial differential field equations of thermodynamics. gravity can be derived by applying the first law of thermody- namics on any local Rindler horizon. Generalization of this From the second law of thermodynamics, we know that method to () gravity, by introducing the entropy gener- every closed system moves towards its maximum entropy ation term due to nonequilibrium nature of spacetime, was state which is an equilibrium state. This leads to the con- investigated in [2]. More attempts to reveal the connection clusion that the second derivative of the entropy should be between thermodynamics and various theories of gravity can negative [36]. The assumption that the second derivative be found in [3–8]. An elegant example is the derivation of the of entropy is negative comes from
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